Vapor Lock

[Squab]

I am the proud owner of a 1989 Wellcraft with a 4.3L Merc in it. Two weeks ago I went out all day and she ran fine. turned off a few time and always started up. When I was getting back to the marina I docked it and tried to start and she would run the die as if it were out of gas. Start then die, start then die. I get it on the trailer and took it home thinking that I was the idiot who relied on the gauge. I put 5 gallons in it on land and she ran fine. No trouble. Took it out this weekend but this time I put 10 more gallons in it and all was well. Started and stopped 2 times during the day. When I was starting to go home she just turned over but no start. I took both fuel filters off and made sure they were clean. Let it sit for a bit, thinking I Flooded it and she fired up. I pulled anchor and then she sputtered and died. Luckily, I had a friend tow me home and Now I am here. By the way I basically put a full can of StarTron in the fuel over the last two fuelings.

 

[Bifflefan]

Re: Vapor Lock

Vapor Lock, is the fuel boiling, and turning from a liquid to a vapor in the lines, pump or carb bowl.
The best way to check for this, when it is acting up, pull the spark arrester and have someone give the throttle a pump or two. If you see gas squrting its not a vapor lock.

Im more thinking its a heat soak issue with the ignition coil or some other component. After is cools it runs normal again, right?

 

[Aloysius]

Re: Vapor Lock

Welcome to the world of ethanol laced fuel. Probably have a carburetor float bowl full of water/alcohol. Settles out when the engine isn't running. "Fuel dry" is nothing but alcohol, which mixes with both water and gasoline...sort of.

Probably have to remove carb to empty it.

 

[Squab]

Re: Vapor Lock

Well I drained the Batteries out there and did not get a chance to charge them when i got home. And wouldn't you know it, it is raining today so not sure if battery chargers and rain mix. Will try later to charge and start. If it starts fine, then what would my problem be? And how do i fix it

 

[Bifflefan]

Re: Vapor Lock

If it starts fine, then what would my problem be? And how do i fix it

Read below.

Im more thinking its a heat soak issue with the ignition coil or some other component. After is cools it runs normal again, right?

Follow the trouble shooting in your manual to be sure.

 

[Squab]

Re: Vapor Lock

See I think it is fuel related. Could the Starttron have broke some gunk out of the fuel lines and gotten it to the carb? I did put it in neutral and gave gas and saw the fuel shoot into the carb. As for the Wire harness, could it just be a loose wire or something?

 

[Adirondack]

Re: Vapor Lock

"Vapor Lock". There's a term I haven't heard in a long time. Most commonly seen on inline carbeurated engines with stacked uncooled manifolds. Just my thinking that if there's enough heat up in there to boil the fuel out of a carb there's something serious going on. That being said I would start by looking for some of the more conventional problems already mentioned.

 

[Aloysius]

Re: Vapor Lock

Rain. If you have a fuel filler on the gunnel, if the o-ring is damaged, it will leak rainwater into the fuel tank.

 

[Squab]

Re: Vapor Lock

No No, it has not rained here for a few weeks. How can i replicate on water running temps on land? Should I just let the boat run for like 30 minutes then turn if off and see if there is a problem with the harness?

 

[Dshow]

Re: Vapor Lock

I would say vapor lock is very hard to replicate on land, you can't get the speed and load necessary to heat things up. There are several things you can do to reduce the heating in your engine compartment, I know Merc has a service bulleting regarding this and you might also check this thread -> http://forums.iboats.com/showthread.php?t=427262

 

[Squab]

Re: Vapor Lock

Ok so the boat has sat for a full day and I finally charged the battery. When I turned it over i got nothing. I had a partner put it in Neutral and give it throttle and I saw nothing shoot into the Carb. So I guess I am gonna start to trace it back to the fuel tank. Maybe Vapor Lock afterall. Hope I am not just out of gas, I did put 10 gallons in. Keep u posted

 

[Aloysius]

Re: Vapor Lock

"vapor lock" doesn't happen on a cold engine. Maybe the accelerator pump isn't working.

What kind of carb?

 

[Squab]

Re: Vapor Lock

I believe it is a merc 2 barrel. I tried to start it again but this time i put a cap full of fuel in the card and it tried to fire. Gonna investigate the fuel lines and filters again.