Vapor Lock?

[jca1971]

Twice now after re-fueling my boat I've had problems restarting my engine. First time I re-fueled my boat on the way home from the ramp. When I got home to flush the motor, the engine would not start. It would turn over but not fire. After letting it sit overnight, it would fire up right away the next morning. A month later, I re-fueled while on the water. Engine started up fine and I cruised for about 90 minutes. Anchored to do some fishing and lunch for about an hour and when I went to start, the engine would not fire. Had to be towed back to port by Sea Tow. When I got home and tried to start the engine, it fired up right away.

I've done a search to see if anyone has had similar problems and it seems what I might have is a vapor lock. My boat just had it's 100 hour service and is still under warranty so I'm taking it back to MM to have them take a look.

One other note, recently when I fill the tank with gas, the pump does not shut off automatically. Gas just comes shooting out of the fuel fill when full. This has happened the last 3 or 4 times I've filled up with gas. So I'm guessing the fuel vent is clogged or not functioning properly. Don't know if this has anything to do with my problem but I thought I'd mention it. Initially, the gas pump would shut off when my tank was full.

Anyone have any idea what could be causing my problem? I have no idea what the MM tech's will say as I'm pretty sure when they go to start to boat cold the engine will fire right away with no problem. I don't want to get stuck on the water again and have to be towed back to port.

Thanks.

 

[jitts3]

I've never experienced or heard of vapor lock on anything fuel injected. It sounds to me like a heat/electrical problem. From there, sombody else take it away. I'm not familliar with MPI Boats. Just Cars.

 

[tdappleman]

When I got home to flush the motor, the engine would not start. It would turn over but not fire. After letting it sit overnight, it would fire up right away the next morning. A month later, I re-fueled while on the water. Engine started up fine and I cruised for about 90 minutes. Anchored to do some fishing and lunch for about an hour and when I went to start, the engine would not fire. Had to be towed back to port by Sea Tow. When I got home and tried to start the engine, it fired up right away.

One other note, recently when I fill the tank with gas, the pump does not shut off automatically. Gas just comes shooting out of the fuel fill when full. This has happened the last 3 or 4 times I've filled up with gas. So I'm guessing the fuel vent is clogged or not functioning properly. Don't know if this has anything to do with my problem but I thought I'd mention it. Initially, the gas pump would shut off when my tank was full.

Even without MPI, I don't see how this would be vapor lock as it's probably sitting long enough to cool down - even in FL this time of year. Does the engine turn over at all? Any clicks, etc? Does wiggling the throttle or kill switch have any affect? I don't have MPI - but can the Idle Air Control valve fail like this? Do the newer boats have a slave solenoid? Starters can get hot as well and not want to turn over.

For the fuel - nothing is wrong with your boat - it will not shut off automatically like when you fill up a car. You have to listen for the vent sound to change - mine makes a little whistle when it's almost done. It will shoot out the vent if you continue to fill it up.

 

[jca1971]

Even without MPI, I don't see how this would be vapor lock as it's probably sitting long enough to cool down - even in FL this time of year. Does the engine turn over at all? Any clicks, etc? Does wiggling the throttle or kill switch have any affect? I don't have MPI - but can the Idle Air Control valve fail like this? Do the newer boats have a slave solenoid? Starters can get hot as well and not want to turn over.

For the fuel - nothing is wrong with your boat - it will not shut off automatically like when you fill up a car. You have to listen for the vent sound to change - mine makes a little whistle when it's almost done. It will shoot out the vent if you continue to fill it up.

Wiggling the throttle or kill switch makes no difference unfortunately. Basically from what I've read on the MerCruiser website it sounds like a vapor lock. MerCruiser recommends running the blower and opening the engine compartment to cool everything down. They also say idling the boat for 3-4 minutes prior to shutdown helps as well. I will be curiously as to what MM says after their diagnosis.

Thanks for the tip on the fuel. Glad to know nothing is wrong there.