my boat vapour locks

i have a 1994 sport nautique with a 5.8 HO efi. the first year of efi and it has problems with vapour locking it will be fine the first time and then if i go to start it for a second time after letting it sit for bout and hour or so then it wont start. just wondering what to do? help

Brandon, Just wondering why you feel it's vapor locking besides it not starting after sitting for the hour? It's rare you get vapor locking on a marine engine. Any modifications to the engine?

well i left the engien cover open after everytime i used it this past weekend and it fired fine everytime. but im still not sure some people i have talked to said it was vapour lock. cuz i would use it and then let it sit on the beach wiht the engine cover closed and then i woudl go to fire it up and it would tur over fine but wouldnt fire and the fuel pump and stuff would put gas through but i looked at the injectors and there wasnt enough gas coming out and then all of a sudded after a couple of tries the gas woudl start shooting out lots and it would fire up. but after leavin the cover open after every use and letting the gas cool and stuff it would be fine im kinda confused tho

beck wrote: and whats the clothes pin trick bill?

Brandon, The people that are telling you that it's a vapor lock problem will be able you explain this "trick" in detail. Stick with Chris's advice.

I think the problem may be with your high pressure fuel pump. I am wrestling with this problem. I have a 95 Ski Nautique Open Bow with the GT-40 motor. It starts great but after running the boat and letting it sit it won't start. I can hear the low pressure fuel pump but not the high pressure pump (which makes a higher pitched sound.) The pump feels pretty warm to the touch at this point. I think what is happening is as the boat sits and the pump gets hot a sort of vapor lock occurs in the pump preventing it from operating. While the pump is running it stays cool since cool gasoline is running through it.

I spoke with a guy at SkiDIM and he said that this is a common problem with the fuel injected motors before the fuel cell was used. Since I didn't have the problem before, I am planning on buying a new high pressure pump (around $330) and hope to get another 13 years out of it.

I hope this helps.

If your set up is like mine, which I think it is, the low pressure pump brings the gas from the tank and the high pressure is connected to the other end of the low pressure pump and it pushes it to the injectors.

I replaced the low pressure pump a couple of years ago and it seems to still be working fine. When the boat is not starting I can hear the low pressure pump run when I turn the key on. I am having problems with the high pressure pump. I checked to make sure it is getting power. It just doesn't seem to work until it has cooled down. I ordered a new pump today and I hope it does the trick.

Hank, can you take a pic of that pump and post?

I am have almost finished my stringer replacement and will move on to the floor supports this weekend! My question is should I use some kind of hardwood plywood to frame my new boxes? The factory used 1/4 inch and glassed over it and put a wood cap on top.(it looks like a wood "I" beam at the top. Is there a fur plywood??? Thanks

That picture is the lower pressure pump. The high pressure is a smaller cylinder and connects to the low pressure pump. I'll try to take some pictures when the pump arrives.

beck wrote: yea but vapour locking isnt driving and then it quits it is when its sits and the gas heats up and boils and then it doesnt work so in other words chris is wrong. and my ignition system and cells and everything i have tested and are perfectley fine. so the only thing left is vapour lock.

well that's where your completely an idiot and don't have a clue and it can and will occur driving down the road and since you know the problem why the hell are you asking for help clown.

and I would go ahead and waiste some more money by buying new fuel pumps would never look at replaceing the ignition or fuel control relays, dumb dumb dumb folks here on this issue. Hope you catch up to your tail but I doubt that you ever will.

Oh and be sure to test everything when it is cold because that's not when you have trouble and that won't tell you *************** or when they would fail, they fail once they get hot due to thremal expansion within the unit idiots. Glad I've been gone for the last week while you clowns have been chasing your tails.


and since your so keen on things carb'd motors can vapor lock, fuel injected motors don't kind of hard to boiling it under 50 lbs of fuel pressure pretty easy with 5 lbs of pressure. So after you waste a grand trying to fix it maybe you will take it to someone that knows what the F they are doing because you don't have a f 'n clue.

by the way the ignition system would never tell the computer to shut down the fuel then again the presure regulator doesn't effect the fuel flow either or the relay's control the pumps so keep looking at the throttle body to try and figure out whether or not your catching up to your azz doubt it. But then I'm sure the fuel rail and fuel line are laying on the intake or block causing a vapor lock too.

Isn't that a picture of the High Pressure Fuel pump? I have a 97 SN and can't get it to turn over. It feels like its not getting any fuel. What seems to me be the low pressure fuel pump, which is black and about the size of my fist, I think it is not working properly, I can feel it vibrating so i know its getting power but its not sucking any gas. Is that pump on all the time when the boat is running?