Today we skied for the best part of the morning. Great time, hardly a boat on the lake. We owned the main channel which runs for about 2.5 miles. Here was my problem. After skiing, we floated around and swam for about 45 minutes. Now it is about 97 degrees up here in Pa. and when I went to start my engine, it sputtered a bit and shut down. I restarted numerous times with the same result. I even went into gear to try to move but it sort of backfired and sputtered and shut down. I turned on the blower, maybe I should have in the first place, waited a bit, then opened the engine cover for a minute or two. When I tried again, boom, started right up no problem. I ran at about 30mph for a while to blow it out. What do your folks think may have happened there. This NEVER happened before. Boat is a Chap216 2001 model with as said before has a MAG 350 with a Gen 2 Alpha and a four blade stainless prop. When I came home and backed down my driveway, I put on the ear muffs with the garden hose just to try again before I backed into the garage and, boom, again, started right up. What went wrong here.

Sounds like vapor lock to me.

Oh...check thread on vapor lock by 4lake bums...same issue.

If it's carbureted, vapor lock.

If it's FI'd, gonna be a lot tougher.

Is this the same question that was also posted in the Boating Forum section?

1) Cool the fuel line parts and path.

2) Replace the fuel pump.

3) There are many other paths to follow also, I suggest that you try #1 first.

4) Is last year's gas still in the tank or part of it or is it all gone and there is only two week old gas in the tank?

5) Check the float bowl level.

6) Check if the gas and gas lines had any restictions, like old filter, gas cap vent not really working up to snuff, gas tank shut off valve not clean...

7) Check all the gaskets for slow leaks.

Sounds like something along the lines of "vapor lock" caused by high under engine box temperature. Especially the fix of opening the lid of that engine box and running the blower to cure it.

Same exact thing that happened to me this weekend. It ran fine the rest of the day. Quite interesting. If you have any more issues please post as I will do the same if it continues.

I am going to change the fuel filter and check the fuel pressure. If not that the water/fuel seperator.

I am going to do nothing until I run it again this weekend to be sure. Hopefully it was a one time thing due to the high temps, however it has never been an issue before.

Sometimes you can get vapor lock early in the season due to still having winter blend gas in the tank. It vaporizes at a lower ambient temperature.

I had a similer issue on my 350Mag... turned out to be a dodgy spark cable that goes to the coil.. once it started it appeared to run okkay (although it probably was running on 7 cylinders sometimes).. however when i went to start it.. it looked like it was going to start.. but didnt ebd up startying.. did a backfire every once in a while when starting..

I've had the same problem twice this year (See Back to Back Towings under Engines, Drives & Props). I'm still working on mine and will keep you posted.

TT

I'm gonna go against the grain here and bet the issue is gonna be in the ignition system.

Nick, do a quick check for spark the next time she acts up on you. If it's good at least you can cross it off your list of possible causes.

I'm with T Square check for spark when it is acting up, could even be a weak coil

on mine the cable wasnt fully broken, but had a crack.. when the engine was not moving it appeared okkay.. when it was starting, the movement in it made a not so good spark.. hence why it was difficult to find.. thay checked the computer, all was okkay etc.. but 50% of the time it didnt want to start.. before this would start within 2 seconds each time..

I also have been dealing with this on my 2005 5.0 MPI.

It is a pain to have a pretty new boat do this when fuel injection should help.....

It happened to me this Sunday, first time out this year, hopefully it is the (old) gas, which did not help matters....

Hey everyone, thanks for all the input, I talked to my dealer the next day and he felt that it was in fact a vapor lock. I have been out on really hot days three times since and when we go to sit somewhere to swim, I run the blower for a bit, let the engine idle for five minutes or so before shutting off and even opened up the engine cover just to air out. Not one bad start since. Yesterday we skied for over an hour but it was not so darn hot and I did not even do all the above and she started proper every time even after sitting off while we swam for 45 minutes. I will keep that experience in mind for those really hot days in the future and take appropriate actions as above. Thanks again for the input.

My volvo 5.0gxi will take a several cranks to start after it has sat a while after being run on a hot day. It never did it until I moved to MO/KS where we'd routinely boat on 95+ days. If it's in the 80's it always fires right up. But on really hot days it will crank a while to start after sitting and hour or so. I know a guy with a Merc 5.0mpi that does the same thing. IMO it has to be vapor lock since it never does it on cooler days. Now that I live in Illinois and 95 degree days are rare, it always fires right up.