Engine Surge at WOT |
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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Well we will get to the bottom of this one way or the other. Right now shes sitting at 1300 hrs. Ill just keep plugging away at it and eventually get it figured out. I really appreciate everyones input, what a great resource this site is. Were pretty lucky
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levin
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63 Skier
Grand Poobah Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4269 |
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Mark, like a few have said I think you have multiple problems. If you aren't burning any oil the valve seals are probably OK, or at least OK enough to ignore for now. So you likely have a combination of ignition and fuel delivery issues. Since timing is straightforward and can be easily measured, tackle that first. You need to get your total timing into range, 22 degrees just isn't in the ballpark of what you should have. The advance mechanism isn't working correctly. Once you get the timing solved, you can run it and see where you are, read the plugs again after cleaning them or installing new. It's possible that will do it, that your lack of advance isn't allowing a complete fuel burn since it doesn't ignite early enough in the stroke. If not you can then turn to the carb, but at least at that point you'll know your ignition is working properly. |
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'63 American Skier - '98 Sport Nautique
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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10-4 Dave. I know this doesnt fix the timing issue but what if I were to set the timing at the 3500-4000 range to 28-30 degrres and let the initial be where it ends up? Install new plugs, run it this weekend and check them out?
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levin
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63 Skier
Grand Poobah Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4269 |
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You won't be able to run it with 16-20 degrees initial, that's way too advanced for idle.
Echobravoecho in a post above recommended really getting into the advance mechanism. It's not hard to get at, and simple enough to see if it's working smoothly. Maybe someone prior to you messed with it, changed out the springs? |
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'63 American Skier - '98 Sport Nautique
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hotboat
Gold Member Joined: March-28-2009 Location: Conn Lake Pa Status: Offline Points: 814 |
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Don't worry on the initial, on this low of a compression motor it should be no problem and will idle much better. Get that timing at 4000 up in the 30-36 range |
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Brian
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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Thanks guys, Ill mess around with it and see how it goes Saturday. Ill keep you guys posted
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levin
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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One more question. Im doing all this work in my garage with motor having no load. Im assuming if I advance the timing more, it needs to be checked under load, like running down the lake wot or at least 3500 rpms and check timing then to see if its still in ballpark?
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levin
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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The advance in this application works strictly on RPMS. So, load doesn't matter as far as the dizzy is concerned.
I'll let other's weigh in on whether or not you want to rev it over 3.5k rpms in neutral though. I wouldn't go over 3, but that's just opinion. |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Here's a weird one I'll throw in there. Luchog ran across a situation where the spring that holds the cap contact to the top of the rotor was sticking somehow. Worth exploring:
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=19567&title=distributor-cap-carbon-pill-issue |
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6150 |
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Lack of full timing advance won't cause a surge. It will just make it doggy all around.
Inaccurate advance IE. jumping around would cause a surge as it made more and less power but that's unlikely. Just rev it through the rpm range until it doesn't advance anymore. 3500 rpms in neutral won't hurt a thing. Make sure the timing reading you see advances in a linear motion and it's not "sticky" or "jumpy". |
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peter1234
Grand Poobah Joined: February-03-2008 Location: United States Status: Offline Points: 2756 |
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you are way over thinking this problem. get your timing close get it in the water get it under a heavy load run it at wot and see if it leans out . it will pop fart detonate and just feel like it wants to rev higher than it does.
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former skylark owner now a formula but I cant let this place go
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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I hear ya Peter, plan on getting out Saturday morning, will update on how things ran
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levin
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boardersdad
Senior Member Joined: June-18-2013 Location: Wisconsin Status: Offline Points: 409 |
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For that heavy load--you could pull a bunch of tubes! At dawn when the skiers want the glass!! Through the middle of the course!!! lol
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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Ha, not a chance! Skiing and footn only. We've had our Ski for almost 4 years now and not once hooked a tube to it and dont plan on ever doing so!
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levin
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Here's a summary of everything I picked up from the thread:
Replaced: -Carb 2010 -Fuel line -Anti Siphon Valve -Fuel Filter -Coil -Cap -Rotor Checked Cleaned or adjusted: -Adjusted secondary float -Cleaned needle and seat -Checked and adjusted spacing of electronic ignition pickup -Timing -Advance A couple questions left un-answered: -Secondary opening? -Carb replaced in 10’ Where from? Is it new, new, or from a bulk rebuilder? What lead to the carb replacement originally? -Arching near coil? Here's the one I'm most interested in. We all kind of assumed coil. You replaced the coil, but that ultimately didn't change performance. Did you ever check to see if that same arching was eliminated after the coil was replaced? |
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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Brian, to answer your questions.
1. When I bought the boat it was sitting in a garage for 3 years without any use. The carb was pretty fouled up and the secondaries were stuck shut/hard to move by hand. At time I didn't know to much (still don't) about these boats. So of course I took it to the nearest dealer where they tried to rebuild it but decided to replace with a new one. After replacement didn't have an issue till next season. So pretty much I have been fighting this since we've had the boat. 2. As far as arching goes, I have not noticed it but will definetly check for that again now that you mention it. 3. Now for the secondaries, I'm not sure but will find out Saturday. Plan on taking doghouse and flame arrestor off, having wife drive while I check things out. Oh yeah, you can add new fuel pump to the list also, replaced that last year. Any other things I should check, was planning on advancing timing to 32-34 degrees, replace plugs, replace fuel filter, maybe check secondary float (see if its parallel upside down), clean needle and seat again in secondary bowl? |
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levin
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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Alrighty guys, Im at the quarry now and just did a wot run with wife driving and I have no secondaries opening! Finally found the pesky problem. Now the question is what do I do fix it. We were running 36 and nothing and punched it and they opened a little. Next run was at 36 and they were closed and then punched it to wot and they remained closed with no fuel flow. Opened them by hand and she really came alive. Hopefully this is a minor fix l, but cant wait to resolve this. Look forward to your responses
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levin
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Take the actuator diaphram off - I bet it has a hole in it.
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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peter1234
Grand Poobah Joined: February-03-2008 Location: United States Status: Offline Points: 2756 |
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I bet you are right cant you also check the diaphram with a suction tube? and your mouth?
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former skylark owner now a formula but I cant let this place go
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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Well i took of the top of the diaghram actuator and the rubber looked ok, didnt see any visible holes. How do I go about testing the diaghram to see if thats the issue? How do I do the suction tube process and what am I looking for?
Thanks guys |
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levin
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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I can do that Chris, but I could use a little guidance on this. What should the process be for tracing the vacuum path? How do I test to see if there is a leak? and how do I test the diaghram to see if there is a pin hole in it? Sorry for so many questions, but I have never really dug into any carbs before besides checking float adjustments, so I am definetly a newbie to this process. I'm more than capable of doing so, just need my hand held along the way. Thanks
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levin
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baitkiller
Platinum Member Joined: October-11-2011 Location: SW Florida Status: Offline Points: 1693 |
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Use a can of carb cleaner and with the engine running squirt a bit of cleaner at suspect areas. Increase in RPM signals a leak. Check the base gasket and all around the intake plenum as well.
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Jesus was a bare-footer.............
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Well, never had this particular problem either. I usually just take things apart & considering the theory of operation, look for something that has changed.
What have you got to lose? |
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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I'd maybe start where the secondary housing meets the rest of the carb (body or metering block, I'm not sure?)
But anyway, there's that tiny cork casket in between there, that could have been left out etc. |
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5778 |
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Mark, you could be chasing a leak or a blockage. Todd W's boat had a similar issue a few years ago and he found the vacuum path to the secondary diaphram was blocked. The circled area on the diagram below.
edit, exactly what Brian above is referring to, either as leak or a blockage there could cause your issue. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21169 |
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Agree with Alan... Bet that circuit is at least partially plugged up. The blockage is more likely to be on the carb body side of that circuit as opposed to the diaphragm body... Be sure to check both sides.
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levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
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Ok, so Ill take the secondary diaghram off and apart, Im assuming I should take some carb cleaner and blow out with compressor?
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levin
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backfoot100
Platinum Member Joined: January-03-2007 Location: United States Status: Offline Points: 1897 |
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You shouldn't have to take the diaphragm housing apart. You should be able to take it off the carb body intact. Get a cheap vacuum pump at AZ or anyplace else. Put a vacuum on the vacuum port and if everything is good, you'll see the secondary rod move like it's supposed to as you pump it up. Hold the vacuum and make sure it doesn't leak. If that's all good don't mess with it. Everything is good as a unit and the problem has to be in the carb body itself. |
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When people run down to the lake to see what's making that noise, you've succeeded.
Eddie |
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JoeinNY
Grand Poobah Joined: October-19-2005 Location: United States Status: Offline Points: 5698 |
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Vacuum Pump, I guess that would work, I just put the thing to my mouth and use the lungs, seriously you should be able to suck on it and pull in the rod, block it off with your tongue and it should stay in. Then if it passes as Eddie mentions you should move onto the carb body. |
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