Timing
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=30303
Printed Date: October-06-2024 at 2:38am
Topic: Timing
Posted By: cboland
Subject: Timing
Date Posted: June-16-2013 at 8:04pm
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I did a tune-up (cap, rotor, plugs, etc.) two summers ago and the boat has never idled quite as well since. After setting/checking the timing and dwell and making sure the mixture screws on the carb are set properly, the boat still seems to idle rough. It won't cut off, but it just isn't as smooth and there is a vibration in the boat. It seems like when I set the timing as far as 30 degs. it idles much smoother than at 10 degs. where I know it is supposed to be. Does anybody have any ideas as to what would cause this phenomenon or what I should be looking for to get her dialed right in? -Bud ------------- Bud 1999 Sport Nautique |
Replies:
Posted By: SNobsessed
Date Posted: June-16-2013 at 10:28pm
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Maybe you have a bad plug wire. Disconnect them 1 at a time (wear gloves) to see if you have a dead cyl. Also check firing order, you wouldn't be the 1st to cross 2 wires. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: cboland
Date Posted: June-17-2013 at 12:24am
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I am wondering if its a bad wire too. It turns out the condenser in the tune-up kit was faulty so I guess it's not unrealistic that there could be a bad wire too. I swear I have the order right, but it can't hurt to check again. Thanks. ------------- Bud 1999 Sport Nautique |
Posted By: backfoot100
Date Posted: June-17-2013 at 10:31am
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How does it run throughout the rest of the RPM range? ------------- When people run down to the lake to see what's making that noise, you've succeeded. Eddie |
Posted By: cboland
Date Posted: June-17-2013 at 10:39am
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It runs perfectly fine once you get it above idle. Very smooth and strong out of the hole as it should be... ------------- Bud 1999 Sport Nautique |
Posted By: backfoot100
Date Posted: June-17-2013 at 12:46pm
Then your wires and the firing order are fine. What I don't understand is how you were setting your timing to 30 BTDC and it was smoothing out? I don't see how it would even run like that. Please explain. ------------- When people run down to the lake to see what's making that noise, you've succeeded. Eddie |
cboland wrote:Posted By: backfoot100
Date Posted: June-17-2013 at 12:50pm
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Also what plugs and plug gap are you running? ------------- When people run down to the lake to see what's making that noise, you've succeeded. Eddie |
Posted By: catamount
Date Posted: June-17-2013 at 1:13pm
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There is a chance that the out ring of your dampener (with the timing marks) is no longer attached securely to the dampener. Apparently, they are bonded with rubber and this rubber can fail after decades of use, shifting your timing marks. Also, did you check timing BEFORE the tuneup? Is there a chance that it was always "off" and you just didn't know it before? If the timing chain slipped, the timing will never "look" right using a gun. There is a guy on the MC forums who has his initial timing set at something like 30 degrees and never figured out why, but gave up searching for an answer as the engine simply likes it there. There is definitely an answer, the problem will be finding it. ------------- 1987 MC ProStar 190 |
Posted By: catamount
Date Posted: June-17-2013 at 1:17pm
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Please read through this thread for some ideas: http://www.mastercraft.com/teamtalk/showthread.php?t=42639&highlight=timing" rel="nofollow - http://www.mastercraft.com/teamtalk/showthread.php?t=42639&highlight=timing ------------- 1987 MC ProStar 190 |
Posted By: Bri892001
Date Posted: June-17-2013 at 3:05pm
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Not sure on the timing thing. Sure you have the right #1 wire? The #1 post on the cap has an expected position, but this can vary depending on where the distributor gear happened to mesh with the camshaft gear. Especially if it was ever removed and replaced. |
Posted By: hotboat
Date Posted: June-17-2013 at 3:43pm
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An engine will idle better at 30 degrees, don't run it above idle though ------------- Brian |
Posted By: cboland
Date Posted: June-17-2013 at 4:03pm
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Thanks for the insights guys. The timing thing really has me confused too. The plugs are Autolites I believe...whatever Skidim sells for the 351 and I set the gap to whatever spec is in the PCM manual. I don't recall what it is. I'll take a look at the MC thread. I sure wish I had checked the timing before doing anything. I've learned my lesson now. Like I said, I had it running pretty well before this weekend at 30 deg. but just didn't like the fact that it wasn't where it "should" be so I started messing with it again. I'm about to just leave it back at 30 since that's what it appears to like. Pretty sure I've got #1 wire (front cylinder on starboard side) ------------- Bud 1999 Sport Nautique |
Posted By: SNobsessed
Date Posted: June-17-2013 at 6:56pm
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Do you have one of the timing lights that can be set for bias? If so, it may need to be zero'd. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: cboland
Date Posted: June-17-2013 at 10:40pm
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Nah my timing light is the very basic model made by Actron. ------------- Bud 1999 Sport Nautique |
Posted By: MAN - GA
Date Posted: June-18-2013 at 11:31am
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Bud, Met you and your buddies couple years ago up at Buffalo's place on Lanier - I remember the issue with the condensor and everyone throwing their $0.02 at your boat that day. Why don't you set #1 to TDC and see where the timing mark is on the damper - this should help verify base timing. Don't know if you have degree tape on the damper that could be in the wrong location or maybe someone bent the pointer that is mounted on the block which would give incorrect info. As a side note I have a digital timing light your welcome to borrow and you can dial timing back to verify the setting. PM me if your interested - I work in Gwinnett and live in Cumming or meet somewhere along the hwy 20 corridor Also if you set #1 to TDC you can then pull and reset distributor so the rotor is pointing to #1 plug wire. |
Posted By: cboland
Date Posted: June-18-2013 at 11:45am
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Hi Mark, Hard to believe it's been 2 years since that Lanier gathering, but yeah that's when all of this started. Like I said, I've actually had it running pretty great, but it just nags me that it's pointing at 30 degrees when it's running well, so I decided to jump back in and tinker again. I was thinking of doing exactly what you said and won't have an opportunity to do so until late this week/this weekend. I'll report back my findings. I appreciate the offer on the timing light. I'll let you know if it comes to that. On a side note, I had a gearhead friend help me rebuild the Chevy 283 that goes in my '59 Chris-Craft. It has no timing indicators on the engine so we had to do it all the old fashioned way - put #1 at tdc, drop in the distributor, and adjust timing by slowly rotating the distributor and listening. That engine runs beautifully, so while I want this Nautique set up perfectly according to specs, I do think there's something to be said for just listening to what the engine is telling you. If you know your boat well, you know when it's running well. ------------- Bud 1999 Sport Nautique |
Posted By: cadunkle
Date Posted: June-20-2013 at 7:06pm
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If you actually have 30* initial and your distributor is advancing properly you'll destroy the thing from detonation. Shattered pistons and rings, hammered rod bearings, and all sorts of unpleasantry are in your future. You need to fix this before running the boat on the water under load, no exceptions. Put a piston stop (either a real one, use a bolt, get creative with an old spark plug, whatever) in #1 and find TDC. To do this rotate engine by hand (socket and breaker bar on balancer bolt) until it hits the stop mark where the pointer is on the balancer. Then rotate the other way until it hits the stop and mark where it is on the balancer. Find the point directly between these marks and you have TDC. This should line up with the TDC mark on the balancer. If it does not, replace the balancer. It could be a bent timing pointer but they aren't going to be 20* off and you would know from looking at it if it's mangled enough to be more than a couple degrees off. Fix this or you will destroy your engine either quickly from detonation or slowly from harmonics and a balancer that allows or encourages spaghetti crank. Either way it must be fixed or things will get expensive. |
Posted By: cboland
Date Posted: June-20-2013 at 8:41pm
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Thanks for the insights. I should be able to check all of this tomorrow night or Saturday morning. Hopefully something simple is off and what you described is not actually the case. It just seems to me if the detonation you speak of were really happening (which basically means a powerful explosion is trying to expand a cylinder chamber that is shrinking in size, attempting to reverse the direction of the piston and the engine) this would be very noticeable in the way the engine is running. In other words, I would think the engine would exhibit either sound or vibration that clearly indicates something is off, not a smooth running engine like it is doing. No? ------------- Bud 1999 Sport Nautique |
Posted By: 89Martinique
Date Posted: June-20-2013 at 9:41pm
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Well, by the time you notice detonation its way past where it actually starts to detonate timing wise. Thats why Pro Tec uses the knock sensor. It listens very closely to pre-detonation. Go to youtube and see the difference between a motor that is too far advanced and when its not. Not much difference but big difference in the cylinders... ------------- Current Boats: 1992 Supra Comp-TS6M PCM 351w HO Pro Boss Pro-Tec Ignition - Full Composite (no wood stingers!) 1989 (3rd Gen) Correct Craft Martinique B/R PCM 351w Power Plus 1984 E-Scow Keuka Lake, |
Posted By: 89Martinique
Date Posted: June-20-2013 at 9:45pm
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If you do go way past it should start to sound like a diesel. My friend 07 f-150 with 5.4l triton is a great example. Once its warmed up, about half the time it starts it runs like a diesel for about 2~3 seconds. Sounds just like the 6L powerjoke haha. Never heard any motor do it other than his... ------------- Current Boats: 1992 Supra Comp-TS6M PCM 351w HO Pro Boss Pro-Tec Ignition - Full Composite (no wood stingers!) 1989 (3rd Gen) Correct Craft Martinique B/R PCM 351w Power Plus 1984 E-Scow Keuka Lake, |
Posted By: cboland
Date Posted: June-22-2013 at 12:13pm
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Well I checked everything out this morning and #1 tdc matches up to the tdc mark on the engine so that can be ruled out. I pulled the plug wire off each plug and did not notice a change in the engine when I pulled #5 and #8. Should you always notice a difference for every cylinder when a wire is pulled? I also noticed that after I had idled the boat a while, shut it off for 10 min to check gap on all the plugs, and then turned it back on again, it actually ran quite smooth for about 30 seconds. After that is when it started to vibrate more. Could that indicate some kind of choke adjustment that should be made? ------------- Bud 1999 Sport Nautique |
Posted By: E4ODnut
Date Posted: June-23-2013 at 11:35pm
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Assuming that your firing order is correct, the mechanical advance mechanism is working properly and your timing marks on the balancer is correct, timing should be "all in" by about 3500 RPM at about 28 degrees BTDC crank. This should happen with a static initial advance of between 8 and 10 degrees BTDC crank. I'd be uncomfortable with any more total advance than that on 87 octane unless you know what to listen for and keep a sharp ear out for pinging (detonation). The 351s don't seem to need as much advance as the GM engines do. As was mentioned, if you set your initial much more than about 10 degrees it will throw your full advance into danger territory. Yes, it will idle better, but the mechanical advance restricts what you can do with it at idle and low rev low load. That's a shortcoming of a mechanical advance only distributor. ------------- Robert 1993 Bayliner 3288 "Hocus Pocus" 351 Fords, converted to tuned port programmable EFI |
Posted By: TRBenj
Date Posted: June-24-2013 at 10:38am
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Yes, the boat should run noticeably worse when you pull any plug wire. Sounds like you either have 5 and 8 swapped, or something is preventing proper spark in those 2 cylinders. Check plugs, wires, cap and rotor. ------------- |
Posted By: Bri892001
Date Posted: June-24-2013 at 10:42am
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On the issue of the boat seeming to run better at 30 degrees initial: Is it possible for the weights to get stuck in the full advance position? Like if the spring broke or something? |
Posted By: cboland
Date Posted: June-24-2013 at 11:32am
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Well, as an update, I had the boat out this weekend and I think I've got it as dialed in as it can be. Timing set @ 10*, idle mixture screws at peak vacuum setting, I adjusted the choke a little bit and that smoothed out the idle, though did make it a little crankier to start cold. To clarify on the whole timing thing, it's not that it idled poorly at 10*, just not as well as when advanced to 20 or even 30, which as I've now learned from the other posts is to be expected. So at this point she's idling in gear right at 600 RPM and pretty smooth. The whole issue with not noticing plugs pulled on 5 or 8 cyl. is strange to me, though. I know they're getting spark b/c it jolted me a couple times when pulling them off. I will swap in some new plugs and see if anything changes. Thanks for all the help guys. I've learned a lot on this forum. ------------- Bud 1999 Sport Nautique |
Posted By: TRBenj
Date Posted: June-24-2013 at 12:05pm
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Sounds like the plug wires are on their way out if theyre shocking you. If the boat runs no worse with them disconnected, and at some points, the boat vibrates worse than others, that means youre not running on all 8 cylinders. Get new plugs and wires and report back. ------------- |
Posted By: cboland
Date Posted: June-24-2013 at 12:16pm
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Will do, but geez that is frustrating. This is not a knock on SkiDIM b/c I think they're a great outfit, but that would mean both the condenser AND plug wires I bought from them have been bad. The condenser gave me fits for a while as it was the very last item I swapped back to the old one since everyone I talked to said that couldn't be the issue because "those never go bad." As soon as the old went back in, engine ran great. Even Vince at DIM was surprised it was bad and to his credit he sent me a replacement for free. I didn't expect wires to be bad too, but what you've said makes perfect sense. ------------- Bud 1999 Sport Nautique |
Posted By: cboland
Date Posted: August-03-2013 at 12:23am
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Well guys, I'm still fighting this issue where I don't feel like the engine is running right. I can get it dialed in and idling perfect @ 600 rpm and then go for a ride and when I come back in the idle is off and eventually drops down below 600 and really starts feeling rough and the tranny starts making that common low idle sound. The thing that has me confused and seems like may be the culprit is the fact that when I pull plug wires one by one, I don't feel/hear any change in the engine when I pull wires off #5 and #8. Just performed a compression test onthe engine and every cylinder is 130 +/-5 so that's good. I put new wires on and the plugs are good. So I am at a loss right now. Anybody have any other ideas? ------------- Bud 1999 Sport Nautique |
Posted By: Bri892001
Date Posted: August-03-2013 at 1:43am
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Couple ideas: I assume you replaced your points when you did the tuneup in question. If yes, did the new points come with an extra metal strap/spring that the old ones didn't have? If yes, did you install it? Another thread mentioned issues when that is left out....although it was only a problem at high rpms. Worth checking anyway. It reminded me because that boat was also throwing stray sparks. The only other thing I can think of is that the distributor itself is faulty. Not sure how it happens, or how to test(others on here might though). I've heard they can wear out and then wobble, not firing all cylinders. |
Posted By: cboland
Date Posted: August-03-2013 at 10:44am
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Thanks for the ideas. Yes, I did install the extra point strap. I'm not sure either how to test a distributor but if any can chime in on that I will check it out. ------------- Bud 1999 Sport Nautique |
Posted By: Bri892001
Date Posted: August-03-2013 at 3:51pm
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Bud, I found this old thread which explains the distributor issue a little more but still not fully. The original poster was able to temporarily change the behavior by putting a little side pressure on the distributor, which was a clue. Before you go too far I'd take a close look at the cap as well, maybe try swapping the old one back in. http://www.correctcraftfan.com/forum/forum_posts.asp?TID=27135" rel="nofollow - http://www.correctcraftfan.com/forum/forum_posts.asp?TID=27135 |
Posted By: cboland
Date Posted: August-03-2013 at 7:50pm
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Thanks for posting the thread, Brian. I had the boat out today and all in all I don't think I can complain too much. Idle was very low when i put the boat in gear cold or after it had sat for any extended length of time, but after I went for a ride to warm up and then came back down, she idled at 600. After a while, it might settle down to 550 which is a little low, but it wasn't a problem. Holeshot was fine and running at speed were great. So, at this point I'm just not sure what to do next, if anything. All told she runs pretty good, yet I still know in the back of my head that if I pull the wire off #5 and #8 nothing happens which bugs me. I've changed out plugs, wires, cap, condensor with no luck. Since she's running pretty good, I'm tempted to let it be and just enjoy the rest of the summer. ------------- Bud 1999 Sport Nautique |
Posted By: 8122pbrainard
Date Posted: August-03-2013 at 8:02pm
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Bud, Is there any radial play in the distributor shaft? This may take using a dial indicator but for $10 at HF, they are worth getting since you can use it for other measurements. ------------- /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: wiscofoot
Date Posted: April-28-2020 at 11:36am
The good old cam-phased 3 valve triton-stroke. Mine did the same, and died shortly after. Now i have a 6L that makes that noise and it is supposed to. ------------- 1976 Martinique |
Posted By: KENO
Date Posted: April-28-2020 at 12:54pm
6 and a half years later this thread awakens from the dead for some reason 
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Posted By: Orlando76
Date Posted: April-28-2020 at 1:09pm
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I just can’t believe Pete says something is worth buying at Harbor Freight. Before you know it he’ll be shopping at Autozone and Home Depot. ------------- Please support The Cystic Fibrosis Foundation 1976 Ski Nautique 351 Escort 1993 Ski Nautique purple and black 351 HO PCM |
Posted By: 8122pbrainard
Date Posted: April-28-2020 at 2:09pm
 ------------- /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: Gary S
Date Posted: April-28-2020 at 3:20pm
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And to think it was just two short days ago he was giving me a hard time about HF....... ------------- 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 |