Bad gas?
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=42362
Printed Date: April-25-2024 at 12:32pm
Topic: Bad gas?
Posted By: jblocal
Subject: Bad gas?
Date Posted: January-31-2018 at 9:51pm
| It’s been about 6 months since I ran my boat on the water. I start it up once week in driveway. Today I took it out and when getting up on plane had a pop thru carb. I backed down and got it on plane but another pop 10 sec later. Fuel is kinda old thinking that could be it. Have full tank so thinking taking some out to add fresh gas or retard timing so I can just burn it in the boat. Would retarding timing help with old gas? When I say old 6-8 months maybe with ethanol gas. I know it could be other problems but leaning towards this right now. Starts right up and idles fine. |
Replies:
Posted By: MrMcD
Date Posted: February-01-2018 at 3:10am
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I have seen old fuel cause issues several times over the years. Bad fuel will burn with a unique smell. Hard to describe but you will know it is not normal. Bad fuel makes the valves start sticking. This can cause popping out the exhaust or intake.If the valves hit the Pistons your heads will need to come off for repair. I hope this is not our problem. Bad fuel burning will shellac the piston tops and valve stems causing the sticking. We usually see this when a person pulls the engine for overhaul then takes a long time to complete the job. Lawnmower shops usually post warnings not to start the engine with old gas. ------------- |
Posted By: KENO
Date Posted: February-01-2018 at 8:45am
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It seems like in old posts from last summer you talk about a low idle and always having to make adjustments. Did you ever get that straightened out? Previously you mentioned putting a new carburetor on and having the same problems you had with the old one.Are you still idling on the transition slots instead of the idle circuit as you mentioned? Accelerator pump working right? How about a little background on those issues and what's been done to it lately as far as tuneup stuff like plugs, wires, type of ignition, timing settings, does the timing advance like it should? |
Posted By: jblocal
Date Posted: February-01-2018 at 11:12am
| Ya last summer pulled the carb a checked transition slots and reset it. Fixed the problem. I have an old carb spacer that’s original that is weird looking. Not sure if that’s part of my problem getting the carb to seal. I didn’t notice any weird smell from exhaust. I have a Mallory distributor that had cap and rotor replaced about year ago. Have new plugs and wires that I can put on. Going replace fuel filter today and make sure no water in it. Having a hard time seeing timing marks so going to have to put timing tape on and remark it. |
Posted By: KENO
Date Posted: February-01-2018 at 12:26pm
Once upon a time you had the spacer on upside down, I hope you changed the orientation like Gary S suggested back then. That's an original Pleasurecraft spacer you had pictures of The bottom joint to the manifold is a pain to seal. Many gaskets don't seal very well there and you end up with a leak.. It's pretty easy to make your own gasket that's a little bigger around the edges so it will seal right or find the right one like an original PCM gasket. I think I'd be sure the carb and distributor are working right before worrying about 8 month old gas being the only issue Make sure the accelerator pump is giving a good squirt too. |
jblocal wrote:Posted By: jblocal
Date Posted: February-01-2018 at 12:46pm
| Ok. I still have it upside down. It didn’t look right when I flipped it over. I’m just going to get new one that is solid. I don’t know what I would do without this forum lol. Appreciate all the help everyone gives me. I post back with results. |
Posted By: GottaSki
Date Posted: February-01-2018 at 12:58pm
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My first suspect is a little condensation in the cap giving some errant crossfiring ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: jblocal
Date Posted: February-01-2018 at 8:18pm
| Started checking plugs this afternoon and 1 side of engine is a mess around plugs. I have raw water leaking from somewhere and it doesn’t really look like it’s the riser. All around the plugs is getting wet and rusty. One of the plugs was pretty bad had lot carbon buildup and was rusty at the end. Going to pull the exhaust to really see what’s going on. Could water be coming from the head? I don’t see any leaks running it on the hose in yard. |
Posted By: jblocal
Date Posted: February-01-2018 at 9:38pm
http://s834.photobucket.com/user/jblocal86/media/6EBB05E0-62D8-4AFC-B234-DD5C7F169AAB.jpeg.html" rel="nofollow"> http://s834.photobucket.com/user/jblocal86/media/93CB9ED5-C1A9-4D1F-A8A1-0B9F0AAD214F.jpeg.html" rel="nofollow">  I’m embarrassed to even show these pictures. Looks more like the manifold is leaking from pic. |
Posted By: KENO
Date Posted: February-01-2018 at 9:47pm
Is this rust and carbon external on the plug like where the boot goes over the terminal? Sounds like prime conditions for a misfire under heavy load like getting on plane. How much bilge water gets sloshed around? Is this a raw water cooled engine? How much salt water run time on the exhaust manifolds? Couldn't hurt to finish the tuneup stuff, definitely changing plug wires as part of it and see how it runs. Edit....I guess i was typing while you were posting pictures Looks like a pretty carbon fouled plug, what do the others look like? |
Posted By: jblocal
Date Posted: February-01-2018 at 11:43pm
| Bilge stays pretty dry. It is a raw water cooled. I think exhaust is about 3 years old. 500+ hours. I didn’t pull anymore plugs think I wanted to pull exhaust manifold first keep crap from going in plug hole. That one looked like it would be the worst one. |
Posted By: jblocal
Date Posted: February-02-2018 at 9:25pm
| Pulled the exhaust today. Snapped all the bolts on the bad side 🤬. The rest of the plugs look good. Can’t tell where water was coming from. There was nothing left of that gasket can’t believe I didn’t have exhaust leak. I have new risers and manifolds coming they were due for replacement soon anyway. Is there anyway to check that manifold to see if it had a problem? |
Posted By: 8122pbrainard
Date Posted: February-02-2018 at 10:07pm
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Cole, You could just fill up the water jacket on the manifold and see if any water get's into the exhaust cavity but, it's best to make a block off plate and pressure check the water jacket. ------------- /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: jblocal
Date Posted: February-02-2018 at 10:16pm
| Ok. thanks Pete! |
Posted By: jblocal
Date Posted: February-06-2018 at 8:26pm
| Ok after spending a couple afternoons drilling out the bolts that broke off I ended up punching thru the water jacket on one of the bolts. I had the bit marked with tape so this wouldn’t happen. I think this might of been where my problem was to begin with. Couldn’t find a leak in my manifold. Either way I’m replacing the head now. This will be my first time doing a head. Should I do both while I have everything apart? Where is best place to get one or a pair? I called summit and they gave me the number to the company that remanufatured the engine but they weren’t to friendly. This really sucks lol. |
Posted By: KENO
Date Posted: February-06-2018 at 8:59pm
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Right, wrong or otherwise, people have been known to use a good thread sealer and never have a problem after that. Some engines, not necessarily a SBF have threads that go into the water jacket on some of the exhaust manifold bolt holes with a stud in that location. You couldn'r do studs with a PCM manifold though cause the nut woulodn't fit without hitting the manifold.. You could bolt the manifold back on with thread sealer and see if it leaks before ripping into the engine further. If you decide you're replacing one salt water cooled head, you might as well do both |
Posted By: jblocal
Date Posted: February-06-2018 at 9:28pm
| Interesting. I have new GLM manifolds looks like enough room for nut. I used reverse drill bits on broken bolts and tried EZ out with no luck. I feel like I’m at breaking point with EZ out. I drilled them all out to the max without getting into threads. They been soaking for days. I think I’m at the point of just drilling and retaping. Is this ok to do? I think I prob need to drill the manifold same size also... I really regret not putting the closed cooling when I got this longblock few years ago. Original engine lasted 25 years raw water cooled was still running when pulled it out. |
Posted By: Duane in Indy
Date Posted: February-06-2018 at 9:42pm
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re drilling bolts and retapping: That will be difficult to "pick up" the lead thread and not end up with a cross thread situation. I would keep trying with the left hand drill bit. worst case scenario would be that you would end up using a heli coil or better yet a Keensert. I feel you are in for a real PITA job. ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: jblocal
Date Posted: February-06-2018 at 10:59pm
| Ya figures. It’s already been a PITA lol. Got to add the Royal |
Posted By: Gary S
Date Posted: February-06-2018 at 11:35pm
Here's more reasons to kick yourself, kits for a Ford are real hard to find since there hasn't been a Windsor marine engine produced in what 15 years? ------------- 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: jblocal
Date Posted: February-07-2018 at 12:03am
| Ya at the time I looked think it was about $1200. Think maybe skidim had them. Havnt seen one lately though. |
Posted By: jblocal
Date Posted: February-08-2018 at 12:26am
| Leaning towards just replacing heads. Bolts are killing me. Doing some research on here seems like most replace with gt40p heads. I saw Clearwater heads mentioned quite a bit. I don’t really want to add any more work for myself going this route and wanted make sure wasn’t missing anything? |
Posted By: Jonny Quest
Date Posted: February-08-2018 at 1:35am
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Lots of options when you do a search on ebay for "GT40P heads" ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: JoeinNY
Date Posted: February-08-2018 at 11:00am
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Big Block Chryslers definitely go into the water jacket on the exhaust manifold studs, and require thread sealant to keep things from getting wet and steamy but it can work. If you need to seal on the threads then you are going to want to keep the most meat in those threads you can. If you have the wallet for it a new set of gt40ps is a bolt on improvement, well you might need to drill out the holes in the head to take the larger bolts required for a 351 vs the 302 they were designed for but you can probably order them that way. Can’t just buy one of those though have to do the pair. Is it possible that gets you into new push rods and rockers yeah sure so you will be at thousand with a set of gaskets and taxes. But she will move out noticeably better and the heads are generally good quality castings and have a decent chance of long happy life in the salt. ------------- 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: jblocal
Date Posted: February-08-2018 at 5:32pm
| A set of gt40p’s are on the way. Hopefully they just bolt right on without getting into anything else like the pushrods and rockers lol. I’m prob already getting in over my head. Some of the best fishing and weather is coming up at the end of the month trying not to miss it lol. |
Posted By: KENO
Date Posted: February-08-2018 at 6:11pm
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Did you get them with the holes for the head bolts drilled out for 351 head bolts? If you didn't here's a thread talking about drilling them out yourself or having a machine shop do it if you don't trust yourself  Also there is talk about what spark plugs to use in the thread. http://www.correctcraftfan.com/forum/forum_posts.asp?TID=41180&title=gt40p-question" rel="nofollow - drilling heads |
Posted By: jblocal
Date Posted: February-08-2018 at 6:37pm
| I ordered from Clearwater had them put brass freeze plugs and told them to drill them out. I have a new set of autolites I guess I can’t use now if someone wants them. |
Posted By: Gary S
Date Posted: February-08-2018 at 9:35pm
Now Ken,depending on what oil I use,what make filter I choose,how often I change my impeller or what type of rag I remove wax with- whats the best brand plug to use?  ------------- 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: Duane in Indy
Date Posted: February-08-2018 at 9:38pm
Deep cycle or starting battery??? ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: Gary S
Date Posted: February-08-2018 at 9:43pm
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My therapist told me to only think happy thoughts after the battery and Quinners tool box incident. ------------- 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: KENO
Date Posted: February-08-2018 at 10:32pm
Your favorite brand of course
|
Posted By: jblocal
Date Posted: February-20-2018 at 9:50pm
| Got it all put back together with the gt40p heads and new exhaust, Started right up and sounds great in the driveway. Hopefully going put it in the water tomorrow after work. I’ll report back with results. |
Posted By: MrMcD
Date Posted: February-21-2018 at 4:11am
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It will have more horsepower and torque with your new heads. A good move on your part. Glad you got it back running again. Since you now have more compression you will want to verify how much timing you have at 3,000 to 4,000 RPM. You need to know the amount at this RPM so you know the engine is safe to run hard. Each head design has unique known timing constraints, some can only accept 28 degrees while others need 40 degrees for max performance. The 351W heads I believe are happy at 35-36 degrees but I will let others with more Ford knowledge advise you. A set back or dial back timing light helps to determine how much centrifugal advance your distributor has and if it advances smoothly without sticking. Once you know your advance you can set your timing at idle to allow the right amount at 3,000. Most want your centrifugal advance fully in by 3,000 for best performance. If you find your distributor allows 24 degrees of advance and you want 36 total timing at 3,000 you would set idle to 12 and your good to go. It is just math. If the distributor does not advance properly this is the right time to fix it. Proper timing makes a huge difference in performance and economy. Hope this helps. ------------- |
Posted By: jblocal
Date Posted: February-21-2018 at 10:43pm
| Great! Thanks! Going have to look into that. Boat ran great today on the water. Throttle was lot more responsive even at higher rpm. I only brought it up to 3500 for a second. Cruised around at 3150 for while and was doing 26knot which feels a little faster. The exhaust even sounds better. Going to check my timing and open her up next time. |
Posted By: tryathlete
Date Posted: February-21-2018 at 10:56pm
How are you determining when detonation occurs? Are you going by ear? Dangerous territory! Are you using 87 octane as your base fuel? |
Posted By: MrMcD
Date Posted: February-22-2018 at 12:40am
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If working on a boat I always assume 87octane. Many times it is all you can find on the water. I like to stay conservative on timing since I have seen many detonation damaged engines in my career . Adding an extra 2 degrees timing can offer a couple more horsepower but in my book it's not worth the risk. You are correct that serious detonation can be silent. You just feel the engine start to lay down on power. I have seen fractured rings, broken pistons, blown head gaskets and pounded out rod bearings from detonation. Most of those guys say the engine was running the best it ever had right before they blew up. I would stay with a known safe total advance number for a 351w with the P heads and with a carburetor. As stated I think he would be OK at 35 or 36 but I don't know so I'll let the Ford experts advise. If it pings at lower RPMs the timing curve is a little fast and it can be slowed down. ------------- |
Posted By: jblocal
Date Posted: February-22-2018 at 11:00am
| I had to put a timing tape on my harmonic balancer and Mark new lines last time I set timing. Marks are gone now I need to remark it. I didn’t hear any pinging running. Going to check it after work today. |
Posted By: tryathlete
Date Posted: February-22-2018 at 12:56pm
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We don’t need vacuum advanc e discussed in the attached link, because our engines are always loaded by the prop (there’s no light load at higher rpm to take advantage of vacuum advance). I really liked this link on the subject of ignition timing. https://www.google.com/amp/www.hotrod.com/articles/set-ignition-curves-create-optimal-performance/amp/" rel="nofollow - Importance of ignition timing |
Posted By: MrMcD
Date Posted: February-22-2018 at 10:35pm
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I did a little forum searching and it is stated that the GT40P Heads have the fast burn chambers so max total timing recommended with a good fuel mix is 32. The GM 1996 and newer Vortec heads are similar in needing less timing than the older head designs for max performance. As hard as boat engines work you might want to start with 30 total timing and tune from there to avoid any detonation issues. Sorry to mislead stating 35 or 36 should be safe. With the old heads that would have been safe but not with the GT40P heads. I run a 1995 GT40 with P heads but it is computer controlled so I have not needed to check timing but thanks to your engine now I know. ------------- |
Posted By: TRBenj
Date Posted: February-23-2018 at 6:27am
| Gt40 has gt40 heads... not gt40p (unless you swapped them). |
Posted By: MrMcD
Date Posted: February-23-2018 at 4:29pm
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Thanks Tim. I know Chevy's, My Nautique has the Ford. Still learning. ------------- |
Posted By: jblocal
Date Posted: March-13-2018 at 11:01pm
| I still havnt got everything 100%. Can’t get my idle circuit to function properly. Idle screws all the way in makes engine idle better. Can’t find any vac leaks. Don’t see any fuel dripping. Pulled the carb cleaned it and checked powervalve. Vac is 14 at idle and compression was 120 on one side 118-119 other. 10 degree initial turning. Thinking either i need rebuild my carb which is pretty new or redo my valve adjustment. Especially after reading recent post on here. Can you tell from those numbers if valve isn’t adjust properly? And if they could have anything to do with idle circuit? Engine starts, runs fine, no noise, even idles damn good but rich. |
Posted By: MrMcD
Date Posted: March-14-2018 at 5:00am
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I'm not a carb guru but if your throttle plates don't close far enough it causes the idle circuit problems. If you can close the throttle more the idle circuit may start functioning better. When they are not closed properly the carb will pull fuel ignoring the idle circuit. If memory serves me correctly the screws on the side of the Holley adjust fuel flow. Screwing them in is supposed to reduce fuel. Look down the primary / front barrels a slot should be exposed with the throttle closed. Open the throttle all the way and look with a flashlight to see the full slot. Do a little reading and you will get dialed in how to set up your throttle plate setting. ------------- |
Posted By: KENO
Date Posted: March-14-2018 at 6:28pm
Is that 14 in vacuum at idle in neutral or idling in gear Here are some representative numbers from a post last year Had 20 in idling in neutral at about 700 rpm
|
Posted By: jblocal
Date Posted: March-14-2018 at 9:58pm
| This is just idle on the trailer. I might be mistaking but I’m pretty sure I gave it some gas and vac actually increased to 20. I ordered some shims and Holley rebuild kit. Going go back thru valve adjustment one more time. Read great post yesterday on here gave me better idea. Think I’m also going drain tank and start fresh with rec 90. I’m about wore out working on it. Seems I’m stuck and going over things multiple times. |
Posted By: MrMcD
Date Posted: March-15-2018 at 12:33am
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In neutral/no load vacuum will increase above idle. When you add load is when vacuum goes away or falls off. The higher the load the less vacuum you have when in gear accelerating. As Keno showed with partial throttle opening your vacuum will vary depending on RPM. In a boat engine is always under load if in gear unlike a passenger car. In a boat at 30 MPH your throttle plates are probably 30% open so you still create a little vacuum, floor it and vacuum will be zero. ------------- |
Posted By: KENO
Date Posted: March-15-2018 at 8:27pm
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14 inches is kinda low and 120 is too with the 40P heads unless your gauge(s) are off. You've probably read about different causes which is probably why you're buying shims. You're probably referring to the link I posted the other day with Shep 72's method, it can't hurt to check. It works good. I'd guess you won't need the shims and that the valves are OK, but you'll know soon. |
Posted By: jblocal
Date Posted: April-01-2018 at 11:24pm
| Update: I ended up needing to shim most of the rockers. Drained tank, rebuilt carb, and fresh plugs. 1 screw is responding now on idle/air mix. Other doesn’t seem to do much. Got the vac at 16 nice and smooth. Took the boat out today and performance wise has done better than ever. The gt40p head seems to have more power and huge improvement over the stock heads. |
Posted By: KENO
Date Posted: April-02-2018 at 4:55pm
| So how's your compression after the shimming? |
Posted By: MrMcD
Date Posted: April-02-2018 at 5:00pm
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Good news, sounds like you got it finally. ------------- |