Possible fuel issue?

[Samuelp63]

Good afternoon.

Little bit of trouble this weekend. Looking for some help.

Two weekends in a row I’ve been left “dead in the water”. Last weekend we were riding about boat started to run a little warm randomly. We shut down. I checked for blockages, leaking water pump, nothing. I thought it was due to a failed fuel tank vent as the tank was under a little bit of pressure which I realized when I opened the gas cap after getting towed in. Didn’t try to fire that day, started a couple days later just fine.

This last weekend we rode around for a couple hours. Started and stopped several times. We were surfing for about 15 minutes (3200 rpms 10 mph) when the boat started to run warm. Stopped, checked everything, all was good. Waited about 30 minutes and boat barely started but ran good. Went for about 45 minutes and boat started to run warm at about the same rpm whole cruising. We beached it, ate lunch, attempted to fire back up about an hour or more later and nothing. Try’s to start. Even run for a few seconds and dies. Turns over fine. I opened gas cap, no suction. Checked fuel filter and it had built up pressure.

Waited about another 30 minutes and it fires up and runs fine.

Boats been serviced. New impeller.

I’m thinking I’m running lean possible causing it to run warm? Would a failing fuel pump cause this?

Any help would be appreciated.


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[cnote]

Sounds similar to an overheat issue we had on 08 Z1, thermostat was the issue.

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[Samuelp63]

New thermostat, impeller, and pump all installed within the last 10hrs.

[bsreid]

We had a similar problem there’s a tiny little screen on the fuel line that got clogged and wasn’t sending enough pressure to the motor. Maybe because the cap was open you weren’t getting the right suction and sucked something up into the screen.

[JCP]

You probably have 2 separate problems. If it always starts good cold but not when hot it could be a vapor lock issue. The fact that it runs good under load when surfing would most likely eliminate a fuel delivery/pressure issue. Not sure on the heating issue. How hot is it running? Any alarms? Post back with what boat you have (year, model, engine) and one of the experts on here will help. (not me)

[Samuelp63]

2000 tige 21v with 5.7 black scorpion.

I never let it get above 190, but I do believe it’s still climbing.

[Samuelp63]

We had a similar problem there’s a tiny little screen on the fuel line that got clogged and wasn’t sending enough pressure to the motor. Maybe because the cap was open you weren’t getting the right suction and sucked something up into the screen.

I may have confused you a little. Cap was never left open. Tank built suction likely do to a gummed up vent hose.

Any idea where to look for the screen on the fuel line? I didn’t see anything on the tank side.

Thank you.

[bsreid]

I believe it was on the engine side of the fuel pump but I was not the one to fix it, so I don’t recall. This was also on a newer indmar, so things may have changed.

[Samuelp63]

So i've been digging here... I think i've got something. I forgot to account for vapor lock.

Failing fuel pump leads to low pressure when the engine is under load. This causes the engine to run lean resulting in excessive heat. Excessive heat leads to vapor lock once i kill the engine. Wait a couple hours, engine fires and runs fine.

Thoughts?

[chpthril]

New thermostat, impeller, and pump all installed within the last 10hrs.

was this for maintenance or were you chasing an over heating issue? A hotter then normal engine can lead to vapor lock.

[Samuelp63]

It was both sir. When I first bought the boat after a few trial runs I realized I needed to go ahead and do the impeller, thermostat, and water pump. That was in August.

I went ahead and swapped the impeller again last month to start the season fresh.

[chpthril]

2000 tige 21v with 5.7 black scorpion.
.

If it has the composite impeller housing commonly found on many of those Mercs, id replace the entire housing. They are known to get out of round and not draw well.

[Samuelp63]

Do you know where I can find the alternative?

[TeamAllen]

Do you know where I can find the alternative?

http://www.cpperformance.com/c-132-m...sea-pumps.aspx

[Samuelp63]

Thank you mike. I’ll get that ordered today. Going to check fuel pressure tomorrow.