Vapor Lock? 1978 restored Nautique
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=23845
Printed Date: October-08-2024 at 9:22pm
Topic: Vapor Lock? 1978 restored Nautique
Posted By: Dishman
Subject: Vapor Lock? 1978 restored Nautique
Date Posted: October-14-2011 at 6:24pm
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Hello Forum members,
I need your help and ideas. I have a 1978 Nautique that I am restoring. I have professionally replaced floor and stringers. This winter she is getting a brand new gel coat head to toe. Top to bottom. I have owned and used her for 2 full summers now. Her engine was rebuilt before I bought her and is working great. I did have the carb. rebuilt this summer. Here is the issue I need help with. If I drive at closed throttle/ clicking gear, or keep her ideling too long. (between skiers) driving in clicking gear for too long like when my kids are learning to ski off the boom, I appear to be struggling with what my mechanic thinks is vapor lock. When I try to accelerate it just boggs out. Sounds like she is getting too much or too little gas. My mechanic thinks the gas is getting too hot creating " vapor lock". His diagnosis might all make sense becauseif I pull the engine box up when driving at clicking gear through channels the problem does not happen as frequently. Or if it is happening and I turn the boat off for 15 minutes it stops happening. The temp gauge always reads well below 180. I always run 92 octane gas with no ethanol. From my description are there any other ideas of what my problem could be? And if it is vapor lock what can I do to fix it? My mechanic says we could try to put some kind of device that cools the gas before it gets to the carb??? What is frusterating is it seems to be getting worse or happening more frequently this summer vs. last summer. The only difference this summer is I had the carb rebuilt and I have a modern fuel filter vs. the original one which was on there when I purchased the boat and started leaking. The boat is going to look like it just off a show room floor next summer when this gel coat is done and I want to not be dealing with this annoying engine/ vapor lock issue. I appreciate any ideas as I am not a mechanic and need help in this area. I have a good one who loves working on this engine but we never got it fixed this summer even after carb. rebuilds and new water seperator fuel filters etc. 
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Replies:
Posted By: kapla
Date Posted: October-14-2011 at 6:45pm
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check the antisyphon valve at the tank exit....might be clogged, thus restricting fuel flow...
------------- <a href="">1992 ski nautique |
Posted By: Dreaming
Date Posted: October-14-2011 at 7:04pm
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Good Idea Kap.... I would also check
- Primary's dripping at idle? - accelerator pump adjusted correctly? - primary floats adjusted correctly? - clean spark arrestor? - are your bow vent tubes clogged or smashed? especially after a floor rebuild? |
Posted By: Dishman
Date Posted: October-14-2011 at 7:06pm
| Thank you. My mechanic thought that too and that maybe it wasn't getting enought oxygen. He said I could even unscrew the fuel cap and if it the problem went away that would be it. That didn't help unfortunatley. I did make sure that valve was clear on the outside. I can check to make sure it isn't pinched from the tank to the outlet though. Thanks for the idea. John |
Posted By: Dreaming
Date Posted: October-14-2011 at 7:08pm
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PS... it's not vapor lock, that only happens when the engine is not running, and from what I understand, it doesn't happen much on boats, although it gets talked about a lot here. The Holley carb site calls it "heat soak" if you want to understand more of the principal and the cause.
another thought - fuel pump is bad, or not providing enough pressure? |
Posted By: Dishman
Date Posted: October-14-2011 at 7:10pm
| Thank you Tacoma for the ideas. The bow vent tubs from the hood scoop to engine box are new and not clogged from the floor rebuild. I will have my mechanic check the other ideas as I don't even understand what they mean. |
Posted By: Dishman
Date Posted: October-14-2011 at 7:25pm
| The strangest thing about this problem is it doesn't happen unless I idel for too long. The rest of the time it runs like a dream. Which make me think the fuel pump, etc. are all working fine. Maybe not though. |
Posted By: Hollywood
Date Posted: October-14-2011 at 7:28pm
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Might be worth trying a new mechanic with fresh ideas. Some diagnosis should find your problem. ------------- |
Posted By: Luchog
Date Posted: October-15-2011 at 2:33am
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this boats arent meant for idling. too much fuel gets on the intake and generates a bogging ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique Commander 351W |
Posted By: GottaSki
Date Posted: October-15-2011 at 1:05pm
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Vapor lock shmaper lock, you need a new mechanic ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Dishman
Date Posted: October-15-2011 at 1:52pm
| Can anyone speculate as to why I don't have an issue if I open the engine box while going through channels? I can fix the problem by doing that. It just isn't a reasonable solution. |
Posted By: GottaSki
Date Posted: October-15-2011 at 3:22pm
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To reduce eliminate heat soak, I think quality base gaskets are essential.
The ones that come in rebuild kits are useless. Without going crazy with phenolics, heavy gaskets like fel-pro between intake and spacer, and spacer to carb provide excellent isolation. They seem almost 1/8" thick. ------------- "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: October-15-2011 at 4:48pm
I agree with the need for a new mechanic or possible an old(Er) mechanic. As for these boats not being meant for idling that's news to me... My experience is Properly running boats will idle indefinitely (a couple hours at least) without any issues. ------------- 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 |
Luchog wrote:Posted By: Luchog
Date Posted: October-15-2011 at 10:12pm
Joe do you think the jetting on this boats is for idling around or pulling skiers? Of course you could idle and this could be aggraviated by another malfunction. But the performance is tuned for higher rpms. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique Commander 351W |
Posted By: GottaSki
Date Posted: October-15-2011 at 11:17pm
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The mains should be doing nothing at idle.
Given how conservative the cams are, I concur with Joe, they should idle indefinitely. A 2-3 hour blub is nothing. A boat that can't has something amiss. ------------- "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: October-15-2011 at 11:20pm
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The jetting has nothing to do with idling on a modern 4 barrel carb (newer than mid sixties) there is compromise necessary between the two. Ski boats need to idle plenty ------------- 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: Luchog
Date Posted: October-16-2011 at 12:41am
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yes you are both right on the jetting, I didnt give it enought brain time and 9 hours under the sun today must have done some damage.
Agreed, and no issue should arise while idling between skiers. I will stand on my though, this boats are not meant for idling. That doesnt mean you cant or that it will harm anything. The overal design/tune on this engines is for a different use, fuel mixture, plugs heat range, valves, etc. Of course, this on the theorical case the boat is mainly used at idle speeds. On the subject, carb tweaking is in order. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique Commander 351W |
Posted By: Dishman
Date Posted: October-16-2011 at 4:03pm
| Well if anyone knows of a good mechanic that is a specialist with the Ford 351 or these holley carb's in the state of Minnesota I would trailer them my boat. I am skeptical though as my guy is a 30 plus vet and prefers working on this era of engine in both cars and particularly boats as he owns his own shop. I have A Century Resorter with a chevy small block and a pontoon with an Merc. I/O and there has never been anything he hasn't solved. And because he maintains them I don't have many issues to begin with. I would be up for trying if someone knew of someone better. I wish it were as simple as a carb adjustment but I doubt that is what it is going to be. |
Posted By: SNobsessed
Date Posted: October-16-2011 at 11:18pm
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Don't give up, don't throw money at it either. It is possible this guy is right. I have had cars in the past that loaded up when hot, probably were set too rich. Carbs can't adjust on-the-go like FI can now.
There is a reason for this problem, you just need more data. Get a IR thermometer (they are cheap now) & take some temp readings of your engine, carb, etc. Maybe take some readings of someone else's boat under similar usage. If you look close enough, you will detect the cause. Good luck! ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: eric lavine
Date Posted: October-17-2011 at 10:31am
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im starting to think that maybe you might be having a hot coil issue, when the boat does this is the only time you can really try to troubleshoot the boat, I have a hard time with vaporlocks because there are 4.8 million of these boats out there set up identically to yours and you would think you would see that problem alot more often. when this happens if it wont start pop the arrestor and see if fuel is squirting, a vapor like will starve the bowl and the accelerator pump spit.
my hats off to the guy working on the boat, its very hard to troubleshoot a boat when the problem isnt happening, the only thing i could suggest to him is heating the coil and other electrical parts with a heat gun (blow dryer) to try and simulate the problem. popping the lid up will cool many things in the system including the coil ------------- "the things you own will start to own you" |
Posted By: Dishman
Date Posted: October-17-2011 at 1:50pm
| Thanks Eric, Good idea and I think he might have talked about the coil before. It is not hard to make this problem come up. It is becoming very consistent. I just need to have him over next spring and we can drive in clicking gear for 10- 20 minutes and it should rear its ugly frustrating head. It used to be only some of the time which made me think I was getting bad gas. I even switched stations..But it is becoming very predictable now which is only good in that with him on site (always comes to my place and works on it in the water) we should be able to figure it out. Thanks for all the replies as I can print them and share them. He will understand them better than I. Thanks again for the ideas. |
Posted By: fanofccfan
Date Posted: October-17-2011 at 11:11pm
| Just a thought...we had a simliar issue with 78 a few years back...motor ran like crap after ideling around a while...it ended up being a hole in the exhaust blowing co2 into the doghouse. while underway at speed and air blowing thru the vents the motor had the necessary oxygen to burn. while moving slowly there was not enough fresh oxygen for the motor to run correctly. long shot i know but it worked for us. good luck. |
Posted By: SNobsessed
Date Posted: October-18-2011 at 12:01am
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FFF - Now that you mention it, I had an evinrude with bad exhaust manifold, did the same thing. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: fanofccfan
Date Posted: October-18-2011 at 1:28am
| this leak was the hose just aft of the clamps. found out the repalcement hose was very expensive. |
Posted By: Dishman
Date Posted: October-18-2011 at 11:42am
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That is actually a great idea and reminds me of something I forgot about. One of my hoses is attached together with a clamp. It was set to be fixed this spring by a different mechanic ( guy next to shop who replaced stringers) who pointed the potential problem to me. I told him to replace both and then he couldn't get the parts before I was scheduled to pick it up. I remember the mechanic thought they were expensive too. He said that is probably why the guy before fixed it that way. Clamping two pieces together. He said I would probably be fine since it worked the summer before.
So I will fix this either way. Are there any recommendations on what kind of hose to use? Is there a type that would enhance the sound? As in louder. |
Posted By: fanofccfan
Date Posted: October-18-2011 at 4:21pm
| It is easy to find out if that indeed is the culprit. Drive it with the hood open. Carefully. The blower running did not keep up to my leak. |
Posted By: Dishman
Date Posted: October-19-2011 at 9:54am
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I did try to drive with the motorbox open once (after it had started bogging out) and it back fired a little which was unsettling to myself and a friend of mine who both know little about engines. I called my mechanic to check it out. That is when he said to turn it off and try it an hour later. An hour later, after it had cooled, it worked fine and I continued to pull my buddy barefooting. I need to replace those hoses either way.
If the problem started and I tried to drive with the doghouse/motor box open, should the problem solve it self quickly? If it should then this is probably not the issue. It seem like the boat needs to be turned off and something/part needs to cool off. Sometimes...When this problem is happening it is when I try to take off quickly. It just sputters and bogs. But if I back off the throttle a little or accelerate slowly I can massage it's way to faster speeds. It is like it works it self out. I can only get this done if it hasn't been run or idled too long which again makes me think it is heat related. I am replacing those hoses whether it solves the problem or not so thanks again for reminding me. John |
Posted By: fanofccfan
Date Posted: October-19-2011 at 2:07pm
| If the hood is wide open and not just propped up and it is getting a full blast of fresh air then I would assume the problem is not the exhaust leak. |
Posted By: JoeinNY
Date Posted: October-19-2011 at 2:27pm
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It could certainly be an exhaust leak issue or a coil issue or a vapor lock issue (although I got to say a vapor lock would have to be due to a relatively hot running engine in my humble opinion) or even a sticky advance mechanism/timing related issues….
But if it quacks like a duck, and swims like a duck… it’s probably a general carb cleaning/tuning issue. It is the most common problem and it describes your symptoms perfectly. Either an overly richly adjusted idle or dripping caused by improper float levels or nicked up needle/seat assemblies would fit the symptoms perfectly.. even the extra cool air helping a bit would indictate too much fuel. However that may be a red herring and you may simply have an incorrectly adjusted or improperly working accelerator pump that causes you to bog, pop, or possibly die off the line sometimes. I see that at least once a season even on otherwise clean and well adjusted carbs. Personally, at this point in my life if a carb even looks at me wrong I pull that son of a gone off and rebuild it (ok first I check fuel pressure, then I check voltage to the coil, then I make sure the advance assembly moves smoothly since all those things can be done in minutes without taking anything apart). But other than that tear it down. ------------- 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: Ed
Date Posted: October-19-2011 at 3:23pm
| I like the sound of the coil myself. You should post a picture of the fuel line going to the carb. Is it the stock steel line or has it been replaced with rubber? |
Posted By: Dishman
Date Posted: October-19-2011 at 8:40pm
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I talked to my mechanic today about my Resorter I need him to winterize and he is convinced this is heat related. Fuel getting too hot in the carb. He mentioned something about running temp. at 140 vs. 160? He said to prove it we can run it until it starts happening and then completely remove the doghouse while it is still hot. If it keeps happening then he thinks the fuel in the carb. is too hot causing this?
The carb. was rebuilt this summmer so that is fresh. The gas line has been updated. I did this when the original fuel filter holder rusted out and started leaking. New (modern) fuel filter, New rubber fuel line and rebuilt carb. |
Posted By: eric lavine
Date Posted: October-20-2011 at 10:10am
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any problems with your tach?
keep an open mind and just dont concentrate on it being a fuel issue. its so fcn hard to troubleshoot a boat when the problem isnt happening in a shop setting, Im doing one now waisting my time, engine locks up after running on the water, of course the owner is a 30 year seasoned mechanic but cant work on it anymore, so he has all kinds of suggestions, but I always go back to basics, I first start with a simple compression test, thats good so far, now onto the next step...... ------------- "the things you own will start to own you" |
Posted By: eric lavine
Date Posted: October-20-2011 at 10:11am
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and he assures me the flappers are in the exhaust.....we'll see ------------- "the things you own will start to own you" |
Posted By: Luchog
Date Posted: October-20-2011 at 10:57am
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does it fill with water? all cylinders?
------------- http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique Commander 351W |
Posted By: kapla
Date Posted: October-20-2011 at 4:22pm
USCG approved rubber line? ------------- <a href="">1992 ski nautique |
Posted By: Dishman
Date Posted: October-20-2011 at 6:12pm
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I will check on the uscg approved rubber line. But if it is not, that would be a bush league error? worth checking as all these ideas are. I am making a check list for him so thanks for all the ideas.
He always works on the boat in the water vs. At his shop. |
Posted By: 8122pbrainard
Date Posted: October-21-2011 at 9:40am
Maybe! There is a different requirement for the suction side from the tank VS: the pressure side from the pump to the carb. If he installed plain rubber hose from the pump to the carb then yes "bush league". Run from him but even more important run before it blows!  ------------- /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: eric lavine
Date Posted: October-21-2011 at 9:59am
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Luch, not as of yet, dont want to steal the thread here. I think he may have a bad riser? its the 4 cylinder 140, they always have head problems, so i did a quickie comp test to no avail,
im going to run it today again and let it sit and then pull the plugs and see if im getting any water in there ------------- "the things you own will start to own you" |
Posted By: TRIP
Date Posted: October-29-2011 at 4:35pm
So the fuel line is marine specific? I'm also planning to change out mine 'cause a PO has put 3 fuel filters in it. But reading this I should not just go to an auto-parts store and get a new one there? On the OP's subject; condensation in the distributor cap maybe? I had(/have) the same issue and that is what it turned out to be in my case. ------------- http://www.flyzone-cr.com" rel="nofollow - FlyZone Costa Rica Wakeboarding http://www.correctcraftfan.com/diaries/details.asp?ID=8406&sort=&pagenum=1" rel="nofollow - 1997 Super Sport |
Posted By: eric lavine
Date Posted: October-29-2011 at 9:57pm
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Luch, sorry trip, I found my problem, I was back by the engine and was having my guy hit the key, he would hit the key and sure as *************** it seemed as if it was locking, I ran the boat and let it sit again in hopes of catching some water spit and pulled the plugs, did another comp test and was getting a steady 175 across the board....I was seconds from pulling the manifold which is a bit of a project on a 140. so I sat by the engine again with the plugs out and he hit the key in hopes of seeing water spit...the beeotch fcn locked again.
Well, infukinpossible. stood up, scratched the boys, and grabbed a test light and put it on the yellow wire on the starter and told him to hit it again, light went on and the off in the crank positon...it was the ignition switch the entire time, it would hit and then cut out and seemed like it was locking....well I gave the old crotchity 30 year mechanic a bill for my time including, 14 bucks for a switch and i got the wtf?????? so i said look hear buddy, i couldve pulled your manifold, painted it, pulled the head, or mysteriously pulled your head and said i found the problem, it was a bad head gasket, gave you a bill for 12 hundies and you wouldve been more happy, but i didnt ------------- "the things you own will start to own you" |
Posted By: eric lavine
Date Posted: October-29-2011 at 10:00pm
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I think he just felt like an ass, because I took his word that he swore to me it was the engine locking, and then realized it was a 14 dollar part ------------- "the things you own will start to own you" |
Posted By: Dishman
Date Posted: July-25-2013 at 9:22pm
| I think Eric had the answer.. I am hoping. After running great all last summer on non-oxy premium vs just premium it started doing the same crap.. Changed the impeller and rotor but same crap.. Had my mechanic (I am loyal) with me when it was acting up and we are now installing or replacing a prestolite Ignitor ii and the coil. It did not have points but I don't think it was an ignitor ii.. But part of that piece was cracked and loose... Based on this forum and all the other things we have tried..I got a feeling this is going o do the trick. I think when the coil got too hot the piece which was cracked and loose was causing the mis fire after about 1-1/2 hours of use. We will find out tomorrow. Thanks Everyone! |
Posted By: Dishman
Date Posted: July-29-2013 at 10:57am
| EricLavine is the man.. He was right and only going of my crude description of the issue.. An ignitor ii prestolite clamp down and flame thrower coil has finally put this issue to rest. What is strange is the boat worked in Summer 2012 for 50 plus hours but started back with he bogging out issue in 2013. Thanks Eric! |