Vapor Lock? 1978 restored Nautique

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!

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

kapla wrote: Dishman wrote: New rubber fuel line and rebuilt carb. USCG approved rubber line?

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.

Dishman wrote: I will check on the uscg approved rubber line. But if it is not, that would be a bush league error?

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!

Dishman wrote: New rubber fuel line and rebuilt carb.

USCG approved rubber line?

and he assures me the flappers are in the exhaust.....we'll see

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.

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.

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

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.

FFF - Now that you mention it, I had an evinrude with bad exhaust manifold, did the same thing.

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.

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!

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.

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.