1980 SN stalling when hot / won't restart
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=41317
Printed Date: May-03-2024 at 4:17am
Topic: 1980 SN stalling when hot / won't restart
Posted By: bchopkins
Subject: 1980 SN stalling when hot / won't restart
Date Posted: June-21-2017 at 6:46pm
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Hey all, probably should've posted here a long time ago, but alas, I'm here now. I have a 1980 SN that I've been fighting with for probably 15 or 16 months now. This is my last ditch effort at finding a solution before I move on from this boat in some form or fashion. I paid $4200 and i've spent probably $2K at this point so I'm reaching the point where i need to make a decision on whether or not I want to continue on this path. She starts and runs like brand new when she's cold, but ever since the start of last summer, each time I've ran her she's been stalling and dying after warmed up. After running for anywhere between 30 or 40 minutes and as much as 2 or 3 hours, she will stall, die and be difficult or impossible to re-start. Sometimes with throttle or time she'll re-start, but she'll stall and die again thereafter. I've spent time, money and effort on this problem for the last 8-10 months, but I've run out of all 3. To me, I wouldn't be surprised at all if a relatively competent mechanic or experienced boat owner/operator could diagnose and fix this without too much hassle because it just "feels" like that kind of problem, but i'm not that person. Any advise or ideas at all would be helpful. I've listed everything below that has been replaced or repaired in the last 1-1/2 years, either directly or indirectly related to solving this problem: - new electricals (plugs, wires, cap, rotor) - new starter motor - new coil - new solenoid (2 of 'em) - new fuel separator & mount - carburetor rebuilt last summer (twice) - new main fuel line |
Replies:
Posted By: bchopkins
Date Posted: June-21-2017 at 7:01pm
| I should note; engine is Commander 351, Holley 4160 Carburetor. |
Posted By: RammerJammer
Date Posted: June-21-2017 at 7:50pm
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I had this issue the first few months I owned my boat. I simplified the electrical system by removing some mods the PO made (like gunnel LED lighting and ground splices) and I got a new Marine Starting battery (the PO had a deep cycle battery). I have not had the stall/no-start happen again. That was several years ago. I had not yet learned to troubleshoot with a VOM so I can't get more technical than that. Not sure if this helps. ------------- 1991 Nautique Excel, PCM 351, Pro-Tec ignition |
Posted By: 8122pbrainard
Date Posted: June-21-2017 at 7:56pm
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When the engine dies or won't start, do you have spark? What's in the distributor? A EI module? If so, is the coil matched to the module? Does the coil require a ballast resistor. Is the coil getting hot to the touch? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: shadow
Date Posted: June-21-2017 at 8:44pm
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I had a problem that sounds a lot like yours, my problem turned out to be the fuel pump. I installed a fuel pressure gauge and that let me know what the problem was, my boat would run good for 15 or 20 min. and then start stalling, motors don't run very good with low or no fuel pressure, when the engine first started stalling, I would look at the fuel pressure and it was buzzing between 7 psi and 0 psi, installed a new fuel pump and the pressure runs a steady 6 psi. ------------- shadow |
Posted By: bchopkins
Date Posted: June-21-2017 at 8:55pm
Brainard, thanks much for your response. Here's the answer to your questions; 1) Do you have spark? YES 2) What's in the disti? EI 3) Is the coil matched? NOT TO MY KNOWLEDGE, NO Longer answer to question 4, so I'm delineating between it and the others. My diagnoses and repair efforts have circled largely around the coil, to your point. Initially I replaced the coil early last year as part of routine electrical system maintenance with a new one that matched the existing one exactly (which had always performed well). Once the problems started occurring and I researched a bit, it became apparent the the coil i'd replaced with was possibly an "automotive" version and didn't include a ballast resistor which i believe the system requires. So, we replaced that coil with the right one and right away, it seemed fixed, but first launch this season and the problem cropped up again right away. I'll send/attach photos of the parts of the system we're referring to as soon as I can take some this evening Thanks very much for your help here.. |
8122pbrainard wrote:Posted By: bchopkins
Date Posted: June-21-2017 at 9:17pm
Thanks Shadow. That was one of our thoughts too, but we tested it. Even switched it out to an electric pump and then back to the mechanical pump and it maintained pressure in all circumstances. |
Posted By: bchopkins
Date Posted: June-21-2017 at 9:24pm
Thanks Rammer, there are almost no mods on my boat and I've replaced the battery twice unfortunately. I do think it's possible that power delivery is somehow the problem, but if it is, I think it's somewhere else in the system. |
Posted By: scootdogydog
Date Posted: June-21-2017 at 9:41pm
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Three main things you need to start a boat (hot or cold) spark, fuel, and compression. When it gets hot, you can check for spark by pulling a plug and grounding it. You can check for fuel by looking in the carb. I assume that your compression is not your problem. It should be pretty simple to isolate if it's a spark or fuel problem. If you want to try fuel, pour a small amount of fuel down your carb. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=7183" rel="nofollow - 1999 Python 1980 Ski Tique 1968 Mustang WIP |
Posted By: bchopkins
Date Posted: June-21-2017 at 9:57pm
Thanks Scotty, ya, this is the part of the symptom that's kind of hard to describe. Compression is not an issue, as you surmise, but I also get spark and fuel both when the problem happens. As mentioned, it's not that it won't start at all, it's just very, very difficult and then won't stay running. Sometimes with extra fuel and fluttering the throttle it'll stay alive for a minute or so, but then will stall again and die. It acts very much like a fuel, air or possibly power delivery problem, but I'm just stumped on which parts of those systems could be the culprit considering the items that I've already eliminated, replaced or repaired. |
Posted By: scootdogydog
Date Posted: June-21-2017 at 10:30pm
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Have you considered an inline spark tester? That'll tell you when it's starting to die, if you're not getting spark until you give it more fuel ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=7183" rel="nofollow - 1999 Python 1980 Ski Tique 1968 Mustang WIP |
Posted By: bchopkins
Date Posted: June-21-2017 at 10:37pm
I have not, never heard of one as a matter of fact, but I'll look into it. |
Posted By: bchopkins
Date Posted: June-21-2017 at 11:00pm
Here's some photos:   
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Posted By: KENO
Date Posted: June-22-2017 at 9:39am
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Is this a situation where you're running along at 30 mph or so and it quits or is it you come down to idle speed and it quits. If it's the latter, I once had this problem drive me crazy for a while and it turned out to be the gasket between the carb spacer and the engine was in pretty bad shape and as things heated up a vacuum leak at that gasket made idling next to impossible, but let it cool off and things were good again. Not all spacers are the same but here's a picture of the bottom of a PCM spacer where it meets the intake manifold Not a lot of sealing area on the outside and some replacement gaskets just don't fit right so you have to make sure the gasket is big enough to seal all the way around the outer edges It may not be your problem at all but since you say you have spark and fuel when it quits, it's probably worth looking at if it only quits at idle speeds. If it quits at high speeds, it's probably not the issue 
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Posted By: Morfoot
Date Posted: June-22-2017 at 10:32am
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Is that coil Oil filled or epoxy filled? Oil filled coils DO NOT like horizontal installations as a norm. ------------- "Morfoot; He can ski. He can wakeboard.He can cook chicken.He can create his own self-named beverage, & can also apparently fly. A man of many talents."72 Mustang "Kermit",88 SN Miss Scarlett, 99 SN "Sherman" |
Posted By: GottaSki
Date Posted: June-22-2017 at 10:40am
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Also sounds crap in the antisyphon valve, clogged cone screen in the fuel pickup or a clogged tank vent. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: JoeinNY
Date Posted: June-22-2017 at 11:26am
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Lots of good advice above but also two very typical things to look at Low voltage issues due to bad ignition switch or weak wiring... check to see how many volts you are seeing at the coil with the engine on when you are having a problem. Also it sounds to me like you are simply flooding the engine - look down the carb throat when it wont start and if you see fuel dripping that is bad. If it is flooding it will start with the throttle open - don't pump the throttle, don't wiggle the throttle - open it wide open and crank it to allow enough air in to match the amount of fuel you have - then crank it for a bit. If it starts like that then you need to fix and or adjust your floats. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: Donald80SN
Date Posted: June-22-2017 at 11:49am
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I had a 1980 myself and I had a person rebuild the carb who knew what they were doing and upon reinstalling the carb, it did not work properly. I then sent the Carb to Carolina Carburetor Specialist in Wilmington, NC 910-762-4695 (Butch). They once again did a rebuild and actually did a remanufacture of the unit. They found that one of the floats was slightly out of spec or too heavy. Not filled with fuel from a leak, just out of spec. I would of chased my tail forever to have found this. JoeinNY and TimBj, tried very hard to help me at the White Lake Mini several years ago but we could not find the issue. When Carolina Carb Specialist does a remanufacture, they put the carb on a Flow Bench which simulates an engine. They dial it in right there so it is Plug N Play. It was not cheap, but it saved my summer and the boat ran better than ever. I also realize you are in Washington State, but you could ship it to be taken care of. I know one from this site that has used a company in Jacksonville, Florida, name slips me, that sells on e-bay with great results. They send you a remanufactured carb and you send them your core of credit. They have several actual engines on stands that they use to dial in the carbs. I probably would of come out cheaper if I would of just purchased a new Holley, but I have heard people on this site have issue right out of the box with them. I am not able to dial them in. Also, the older carbs have the spacer with the PVC Vent Line on them. The new Holley Carbs have that built in so then I was going to have to find a new spacer. Being the boat was a ultra rare, d*ck Pope family / Cypress Gardens , Bush Gardens, 1980 Master's boat and even pulled the 1980 Moomba Master's I decided a new carb might devalue such a rare boat. In my opinion, it is getting harder to find people familiar with Carbs on the shop level. Fuel Injection has been around so long I consider it a dying art. Maybe I am wrong. ------------- 1980 Ski Nautique SOLD Back to Cypress Gardens 2002 Sport Nautique, GT-40, FCT2, Cover Sports, Tower Bimini, Inc., Wet Sounds Audio System, Star Gazer Wake Edition S. 1968 Ski Nautique, Project. |
Posted By: bchopkins
Date Posted: June-22-2017 at 2:33pm
Keno, thanks for following up. This is worth looking into because the short answer is "yes", it's more problematic at low speeds / idle. I don't want to say it runs great at high revs once the problem starts happening, but it does at least sometimes stay running if I can get it up to 4-5K rpms.. |
Posted By: bchopkins
Date Posted: June-22-2017 at 2:35pm
Oil! I'll see if I can change the orientation, worth a shot! |
Posted By: bchopkins
Date Posted: June-22-2017 at 2:47pm
Not the tank vent because I've checked that, but possible on the other 2. Would the fuel pickup act differently when it's cold vs. warm? I've heard the antisiphon valve referenced before, but I don't actually know where to find it, do you know where it would be? |
Posted By: shierh
Date Posted: June-22-2017 at 2:49pm
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I found loose wires from the trans cut out was causing intermittent issues. also could be fuel. Sort of a vapor lock could be happening, Weak pump or something internal in the carb or if there is a check valve that could be an issue. Carter fuel pump isn't that expensive, if its old then put in a new one. |
Posted By: KENO
Date Posted: June-22-2017 at 3:16pm
The Neutral Safety Switch on the trans won't affect how it runs. It will prevent the starter from turning over at all if the boat isn't in neutral when you want to start it and when the engine is running the NSS is completely out of the picture |
Posted By: bchopkins
Date Posted: June-22-2017 at 3:28pm
Thanks Joe, i'm going out this weekend so i'll get a voltmeter on the coil when i first start it and again when it stalls (inevitably) and see if there's a difference. As far as the flooding goes, there is no fuel dripping when it won't start, it pumps fuel into the throat of the carb as it should when you pump the throttle, but I honestly can't say for sure if I've tried the wide open throttle technique so I'll try that. It just struck me, there's one thing I have failed to mention that never seemed related, but if the main problem is a voltage issue, this could be pertinent. When the issue occurs and i have to try cranking a lot to restart, the starter solenoid sometimes will not disengage even when I turn the key back to "off". It just keeps cranking and i have to shut the battery off to get it to stop. That issue only cropped up later last summer so it wasn't happening when the initial problem started to occur, but possibly could be some sort of clue...? |
Posted By: Dreaming
Date Posted: June-22-2017 at 3:48pm
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double post |
Posted By: Dreaming
Date Posted: June-22-2017 at 4:07pm
+1 I too thought of mal adjusted floats. your carb guy adjusted the floats on his bench, level.... they may need a little tweaking because of the angle your engine sits at. your coil being horizontal for a while may have caused a heat related issue. This might mean that a replacement is needed, not just a relocation. If the damage is already done,you won't know the coil is malfunctioning until it is heated up. IMO intermittent coil problems are hard to diagnose. also to note - your rubber fuel line with clamps is not USCG approved, you need to get or bend a fuel line out of brake line or purchase the flexible one from Skidim. While not USCG approved, you could also get a flexible aviation style hose from the pump to the carb, using AN fittings and a stainless braided fuel line. Jegs and Summit have the Holley side of the fittiings... this is probably way more trouble than just ordering the line from skidim though. one last thing... The transmission switch won't affect your runnability, it only affects the starting circuit. if you question it, an easy work around is to jumper the two terminals on the switch. |
Posted By: GottaSki
Date Posted: June-23-2017 at 10:39am
Yes, they can manifest in peculiar ways, sometimes be good for hours at low speeds then take a fast slalom at 36 instead of 34, or foot, and the boat falls on its face four minutes in. The AS valve is a poppet within the NPT-to-barb fitting on the 90 out of the tank. Totally covert. The cone screen some have, some not. Its sandwiched between the tank fitting, and the dip tube. One has to remove the tank outlet and unscrew the dip tube from the fitting to confirm its presence. it clogs easily due to not much total area Either of these will cause you fits and usually the cause of mistakenly assigned 'vapor lock folklore'. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: MourningWood
Date Posted: June-23-2017 at 1:29pm
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As long as you have spark when the issue occurs, IMHO this is a fuel issue when hot. Friend with an '83 had the exact same symptoms you've described. I replaced the intake manifold gasket and the carb base gaskets and....voila. Cured a hot vacuum leak. |
Posted By: shadow
Date Posted: June-23-2017 at 1:29pm
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I would just install a fuel pressure gauge and the next time you have a problem, look at the fuel pressure gauge, then you would know if it was a fuel problem from the tank to the engine. ------------- shadow |
Posted By: shierh
Date Posted: June-23-2017 at 4:12pm
| go through everthing |
Posted By: dentontx87
Date Posted: June-28-2017 at 2:16am
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I'm having a very similar issue. Starts and runs great when cold, but once it runs for a little while, if I turn it off and try to start it again, it usually won't start and the coil is hot to the touch. Is the coil getting too many amps causing it to overheat? What would cause that if so? Should I just get the epoxy filled MSD coil? Please help. |
Posted By: 8122pbrainard
Date Posted: June-28-2017 at 6:56am
Kevin, Amps no but too many volts maybe. The voltage needed by a coil depends on the type. There are some that are internally resisted to drop the volts from the nominal 12 and then others that require external ballast resistors to drop the volts. You need to tell us more like has the ignition system been modified from original. EI conversion in the distributor? Considering your question on amps, do you have a friend that's more familiar with electrics that can help out? Welcome to CCfan. Tell us more about the boat like how you use it. We also love pictures. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: SNobsessed
Date Posted: June-28-2017 at 10:52am
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Also, some coils don't like horizontal mounting. The oil inside doesn't cover the windings adequately. What coil do you have? ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: dentontx87
Date Posted: June-28-2017 at 2:19pm
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I believe the ignition is all stock. I purchased another oil filled coil from the local nautique dealer. I can test voltage, how much should it be getting? My boat, a 1985 SN 2001, will be used for skiing, wakeboard and tubing. I don't know how to attach photos but it's a sharp boat. |
Posted By: 8122pbrainard
Date Posted: June-28-2017 at 2:26pm
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Around 9 volts to the coil. Does it have a EI conversion? Some EI's you bypass the resistor. Posting pictures, use the "post reply" and not the quick found at the bottom of each thread. Click on the icon of the tree with the up arrow. A browse box will come up allowing you to select anything off your computer. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: KENO
Date Posted: June-28-2017 at 2:39pm
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Pete, Pete, Pete It's time for you to learn how to post a picture from quick reply  You just click on the "full reply editor" (that's the icon to the farthest right that has a diagonal arrow pointing up, then you have all the "full reply" icons and it's the same from there.. I just posted this picture of you in your younger, wilder days using that method to be sure it worked. Nice air by the way 
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Posted By: beatsmd
Date Posted: July-10-2017 at 5:14pm
I've been having the same problem with my 1984 Nautique, and (if I'm remembering right) I never had the problem before installing an electronic ignition a couple years ago. At that time, I installed a new PerTronix 45111 Flame-Thrower II 45,000 Volt 0.6 ohm Coil. It's an oil-filled coil, and it is installed horizontally. Could the fix be as simple as just replacing the coil with a new epoxy-filled coil? If so, which coil should I install? ------------- "This skin and bones is a rental" |
Posted By: cbr1000dude
Date Posted: July-10-2017 at 6:20pm
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I had the same symptoms you and other have and chased my tail for a long time before I fixed it. I made the same mistakes you're making, so don't take this as wrong, but your trouble shooting organization sucks. You don't know if it's fuel or spark, still.. Until you know which is the problem, or if it's both, you'll be frustrated. One thing I learned is this. With today's gas and carbs, it's easy to flood the engine when hot. Someone suggested you open the throttle all the way when it won't start but I don't know if you tried that. I would add that leaving it open for 3 or four minutes with the engine cover open would be better at evaporating the excess fuel if that's the problem. Don't pump the throttle, this only causes the accelerator pump to squirt in more fuel. Turn it over for 5 seconds, and wait, don't move the throttle. Don't want to overheat the starter motor. Try again several times. If it roars to life, it was flooded. If not flooded, perhaps it is starved for fuel. Try putting some into the carb by whatever safe method you prefer. No start? Put the flame arrestor back on. Move on to electrical. Bring an extra spark plug. Disconnect a lead, plug in the extra sparkplug. Hold the threads against bare metal. Have someone turn over the engine. Is there a nice fat spark at regular intervals? If not, it's electrical. I would try going back to points, condenser, and coil wired through a ballast resistor if you have no spark when hot. Sure it's old tech, but with the short hours we actually use boats, they last years.. Give the points a fresh filing to make sure they make contact. At least try this as a test if you prefer. Lastly, if your or other's carbs are flooding when hot, but work great when cold, it could be too much fuel pressure. The floats can barely hold back the fuel at 4-5 psi when cold, add heat,, and they can leak and flood the engine after it's shut off. Today's gas is not as buoyant (I'm sure there is a more accurate term) as it was in 1980. My fuel pressure has been dialed back to 3 psi with a Holley fuel pressure regulator between the fuel pump and carb. Don't get a cheap Chinese one, they are erratic. This provides all the fuel I need for both my 351 and 454, and never floods after a hot stop. I'm not an expert or a trained mechanic, this all all from my personal experience with SNs. I'm just trying to help fellow boaters. |
Posted By: MourningWood
Date Posted: July-10-2017 at 7:22pm
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Another quick test is float level when running (when warm, if you can get it idle briefly). Do you trailer your boat? I ask because this is very hard on the float levels. Floats bounce, get knocked out of adjustment. More sensitive on 'slanted' carb position. |
Posted By: Dreaming
Date Posted: July-10-2017 at 8:41pm
MW - Just curious how the float bounce would be exacerbated by trailering? Seems to me that my boat takes a lot harder of a bounce riding on choppy water than it does on the trailer. I was thinking that the float bowls would normally be full in either situation, essentially dampening any exaggerated bounce of the floats. Can you help me to understand the logic behind your theory? I am curious if you have had experience with needing to re-adjust your floats and how often you check them? (sorry for the total thread jack to the OP), I am open to a PM or a new thread if you were interested in talking it through. 
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Posted By: tryathlete
Date Posted: July-10-2017 at 10:23pm
| I had this exact symptom on an old Supra with Pertronix. The Pickup failed from being left in the ignition on position. Replaced it and all was well. I'd go back to points and condenser as it's not problematic on something you use as little as a ski boat. |
Posted By: MourningWood
Date Posted: July-11-2017 at 12:50am
Ah yes, but when running on the lake, the floats (and float bowls) have a constant and steady supply of fuel to them, don't they.... |
Posted By: Dreaming
Date Posted: July-11-2017 at 1:43pm
| true... but when not running, I suspect the only outflow from the bowls would be a bit of slosh, if any at all, as it usually takes vacuum pressure to suck the fuel out of the bowls into the carburetor throat, at least with a properly adjusted float/needle/seat arrangement. Maybe that is why you mentioned that the angled carb is contributing to the issue? Do you adjust your floats regularly? |
Posted By: MourningWood
Date Posted: July-11-2017 at 2:34pm
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Yes, at least annually. When the boat comes off the lake, the hot fuel will both slosh out the vents and, with a hot motor, evaporate, especially today's fuels. The floats can and do pound out of adjustment. Boat trailers aren't known for an overly-cushy suspension, either. Another item is the float itself. First, they should be brass, not plastic. Over time, even the brass ones can develop pinholes in the brazed seam. The hotter the fuel, the more these will open up, flood the float, and there you are. Test: Get a gram scale and weigh the float. Then immerse in boiling water for a few minutes, remove and re-weigh. (you can't see any leak bubbles in the boiling water, hence the scale). If heavier, replace. |
Posted By: Morfoot
Date Posted: July-11-2017 at 3:09pm
Had the same issue with the 88 back in 2008. Didn't realize the coil that I had purchased in 2007 was an oil filled cooler. (I had done the points to Petronix ignition swap over probably in 2005.) Bought a Pertronix Flame Thrower in June of 08 and have never had a problem since. (knock, knock, knock ) I do however keep the original points setup in the boats toolbox in case the Petronix fails. Keep in mind you DO have to use a ballast resister with the above coil.------------- "Morfoot; He can ski. He can wakeboard.He can cook chicken.He can create his own self-named beverage, & can also apparently fly. A man of many talents."72 Mustang "Kermit",88 SN Miss Scarlett, 99 SN "Sherman" |
Posted By: beatsmd
Date Posted: July-11-2017 at 5:07pm
It turns out I was wrong about the Flame Thrower I installed--it is actually an epoxy-filled coil. I can't remember if I removed the ballast resister or not. I'll have to check when I get home from work. If I didn't install the coil with the ballast resister, can I simply correct the installation by rewiring the ballast resister, or do I need to install a new coil (presumably because the old one was damaged by the improper installation)? ------------- "This skin and bones is a rental" |
Posted By: beatsmd
Date Posted: July-11-2017 at 6:14pm
I'm a newbie, so I may have misunderstood, but after talking to tech support at Pertronix and reading these http://www.pertronix.com.au/assets/pdf/Pertronix_Flame-Thrower_II_Coil_Installation_Instructions.pdf" rel="nofollow - instructions , I think you're supposed to remove (or bypass) the ballast resistor when using a Flame Thrower II coil. ------------- "This skin and bones is a rental" |
Posted By: Morfoot
Date Posted: July-12-2017 at 11:15am
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The internal resistance built into the coil is .6 ohms while the ballast resistor used is a 1.5 ohm resistor. Pretty sure I installed a 1.0 resistor. I've heard here many a time where the Pertronix EI system isn't too reliable but I've had nothing but success with it. I would wire it back in. ------------- "Morfoot; He can ski. He can wakeboard.He can cook chicken.He can create his own self-named beverage, & can also apparently fly. A man of many talents."72 Mustang "Kermit",88 SN Miss Scarlett, 99 SN "Sherman" |
Posted By: GottaSki
Date Posted: July-12-2017 at 12:05pm
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0.6 Ohm coil is well over 20 Amps at the coil at 14.5V even given with some internal Ron of the driver in the Pertronix. I understand there is a duty cycle, but that explains how these burn up with the ignition left on and engine off. These units are actually see more through-current and duty-on at low rpms than high. They claim the Ignit0rII can sink their 0.6 Ohm coil However I have my doubts about its longevity. Sidebar, I think our 20 -40 year old dash wiring (purple wire) is not fit to deliver these currents, as that wire also must power the choke, and alternator energize. Now, If one has the Ingitor , and a 0.6 Ohm coil without external resistance, will cook it in short order, sometimes a season or three. It will sometimes run for a bit, the fall flat. After cooling, work at idle, then fall flat on accel, or some other failure mode. If your Ignitor or IgnitorII has been stressed, then it is always compromised, there is no way to undo the damage made to Silicon by later adding in proper resistance afterward. A new unit and rethink the numbers is in order. Like Tim, my Ignitor has been trouble free, for 20 years myself. But it only saw its first couple years driving a 1 ohm accell coil , and has since triggered high-impedance input to an MSD box, so it sees orders of magnitude less current than it would normally. Pertronix recommends their 0.6Ohm FT2 coil With the Igntor only in a 6V system. If a 6V system runs at 7.25V normally, thats 12.1 Amps continuous. To get equivelant amps in a 12Vssystem running at 14.5V, thats 1.20 Ohms total resistance, suggesting an additional 0.60 Ohms external to use the std Ignitor with reliability.. I attribute Tim's success with his Ignitor to thoughtful selection of an external resistor. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Gary S
Date Posted: July-12-2017 at 12:10pm
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I hear you can get pretty far up that creek with points and get stuck too Tim It seems the newer units have more troubles? Or is it because there are less experienced "mechanics" trying to install them? The neighbor who towed us in used to own several gas station back in the day in New Youk City, he was relating his experiences that he had gone thru up to and including of taking the tow truck and rescuing customers that just had a tune up. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: tjdarland
Date Posted: July-24-2017 at 12:49pm
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Hey everyone. I was going to start a new thread this morning on this exact problem, but luckily you are already a few steps ahead of me. I also have a '80 SN experiencing the exact same problem. It starts easily and runs like a champ at high and low RPMs for about 20 minutes, then loses power and can be difficult to restart. It doesn't cough or backfire, just loses RPMs. When it does restart, it runs smoothly at idle but dies as I start to throttle up. She's got 840 hours on her. Everything is stock on the 351 aside from a new QuickFuel carb installed 2 seasons ago. Points and rotor, plug wires, and plugs are in great shape. My gut tells me it's a fuel restriction/pressure issue. Below is my troubleshooting plan. Any guidance would be appreciated! Before next run: > Check anti-siphon valve. I'm not sure that I have one but will check and, if so, I'll most likely remove it completely. > Check cone screen between tank fitting and & dip tube. > Replace the fuel filter. Might as well, it's easy and only a few $$. Start it up and run it. If the problem reoccurs, then: >Look for signs of flooding--fuel dripping in the carb throat >Check for spark using an extra plug >If no flooding & good spark, pour some gas down the carb and attempt to restart After that... >If flooded: adjust the carb. >If bad spark...I'd be shocked (no pun intended) if it is: I'll cross that bridge if/when I come to it. >If it restarts from gas poured into the carb, but dies shortly thereafter: fuel restriction and/or fuel pressure problem. Thoughts? Thanks in advance for any help! ------------- tjd |
Posted By: KENO
Date Posted: July-24-2017 at 5:40pm
I'm not sure why you'd want to remove your anti siphon valve, since it's a safety feature. Go ahead and remove it and then if you have a fuel line leak between the tank and the fuel pump all that gas in the tank siphons into the bilge till the tank is empty. Nice explosive fuel air mixture just waiting for a spark. You can probably figure out the rest of what happens Just helping you stay out of the burn ward or the morgue so you can finish your troubleshooting
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Posted By: KENO
Date Posted: July-24-2017 at 8:31pm
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TJ I see no mention of the fuel pump in your plan. It can cause just what you're seeing. Why don't you hook up a temporary tank to the fuel pump inlet and see how it runs. Only takes a few minutes to do and it'll tell you whether your issue is in the tank/ antisiphon valve/suction line or if it's the pump or carburetor. Here'a a picture of a temporary tank hooked up on a Mercruiser in a Malibu. The clear line makes it easy to see if the pump is drawing a suction, then I can sit there and watch gas flow. It's kinda like watching paint dry This was hooked up to the suction filter and made it real easy to determine that the problem was on the gas tank side of things, since it ran just fine on the temporary tank, ruling out the carburetor and fuel pump. Turned out to be a suction strainer issue. Of course if it's an electrical issue it won't tell you much. 
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Posted By: tjdarland
Date Posted: August-10-2017 at 11:12am
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Hey everyone. Thanks for all the troubleshooting advice. Turns out my gut was wrong--it was the ignition coil. Easy fix and now she's running like a new machine! tjd ------------- tjd |