Help! Fuel Problem

[Kev]

Engine is a Merc 4.3LX V6 Gen+. Took it out last weekend, got up on plane and road for about 20 minutes, then it died for no apperent reason. Had to wait about 10 minutes before it would restart. This happened several more times throughout the weekend. It appears that it is not getting gas, which makes me think it's the fuel pump, but the mechanic at the marina said it was probably the ignition module. Has anyone experienced this problem before?

Kevin

[MOP]

Both spark and gas could be suspect, theres lots of guys up here to help you out. Tell them what type of symtons it had when it died? :rolleyes:

[Tidbart]

Is this carburated or fuel injected?

I had a problem once, a long time ago, with a used car I had picked up. It would run for a while then die like it was running out of gas. Let it sit for a while, it would start and run some more.
What I found was that the fuel filter had accumulated so much crap over time that it collapsed and clogged, thus restricting fuel flow. So it ran for quite some time. What it was doing was running the bowl level of the carb down slowly and eventually stalling the engine. Simple fix for a pain in the butt problem.
Try replacing the filter(s), its cheap and easy. Also replace the water separating filter if so equipped. Check for water in the filter after it is removed.
If it is F.I. do a quick check on your ignition switch. Check the wires, and more importantly, check the terminals on the back of the switch. See if they move. The rivets loosen over time. The switch is also cheap and has been the cause of many headaches and misdiagnosis. Some mechanics may look to the expensive ignition modules and skip over the simple stuff.
Spend a few minutes on the easy things before you go spending a lot of dough on a fix. If you find the problem great, if you don't, at least you won't have pay a mechanic to do these few simple tasks.
Good luck
Bob

[harbormaster]

The easiest thing to do is run that sucker till it gets warm again and quits. Then check for spark. I had an ignition module go bad on me before. It would run fine till it got warm then it would start arcing and quit.

If you have spark, then it is probably some sort of fuel problem. THEN check your fuel filters.

[Kev]

The engine is carburated. I thought the same thing about the filter, but I pulled it off and it looked fine. I'll go ahead and replace it anyway though.
When I started it every morning, it would start right up, run for about 10 seconds then die. I'd wait about 10 minutes and it would start again and I wouldn't have any problems for several hours. Same thing would happen when I was out on the lake; it'd be running fine, then it would die and not start for about 10 minutes. It didn't sputter or anything, just lost power and died. When it died I smelled gas which made me think it was flooding it's self. The mechanic seemed to think that it wasn't getting gas and said it was probably the ignition module.
A friend of mine said he had the same problem which turned out to be the ICM, but before I spend $300 for a new ICM, I wanted to get a second or third opinion. His problem was that when the engine warmed up, the ICM shorted it's self out, so when it cooled off it started fine. Of course, that doesn't explain why mine dies shortly after starting when the engine is cool.
Harbormaster, thanks for the tip on how to check the ICM, I'll certainly give that a try.

Kevin

[MOP]

If its a heat related thing with the ignition module, you can try routing a vent hose from one of rhe cowl vents to help cool it. Also on engines with module mounted on the exhaust riser they seem to crap out alot less when cooled. Heat makes that stuff unstable.