Possible Fuel Problem

[RMCSURWAR]

Bought a used Regal Destiny 200 (2001) with a Mercruiser 5.0 TKS.
After purchase, had the entire exhaust system replaced (manifold/risers/bellows etc...). Took her out for the first time and she ran great for the first hour or two of just cruising. When we started skiing, the engine would die after running only a couple minutes. The engine would start fine, but would always die after a short time. Could I have water in the fuel tank, and stirred the fluid in the tank enough (while skiing) to move the water bubble to the fuel pick-up? How can I break down the water chemically (don't want to have to drain the tank if I can avoid it). Am I on the right track thinking fuel quality, or is this perhaps something more?

 

[ken_23434]

Re: Possible Fuel Problem

I am definetyly NOT an expert on boats and running issues...

But, water is heavier than fuel, so if you have water in your fuel tank, it would settle out at the bottom of the fuel tank, where the fuel pickup is located. If that was your problem, it should have shown it's self from the beginning.

Regardless, you should use an inline water separating fuel filter to combat any water in the fuel issues.

 

[MikDee]

Re: Possible Fuel Problem

I am definetyly NOT an expert on boats and running issues...

But, water is heavier than fuel, so if you have water in your fuel tank, it would settle out at the bottom of the fuel tank, where the fuel pickup is located. If that was your problem, it should have shown it's self from the beginning.

Regardless, you should use an inline water separating fuel filter to combat any water in the fuel issues.

Usually, the first thing I suspect is the fuel filters, if they have been replaced, then the pickup at the fuel tank,,, sometimes the "mandatory" antisiphon valve (one way, ball check valve) gets clogged up with debri, and, or, the nearby screen in the fuel tank as well. Symptoms are no problem at low speed (low flow) but, cutting out after that at high speed (high flow issues).

 

[RMCSURWAR]

Re: Possible Fuel Problem

Thanks Ken and Mikdee;

I'm having the fuel filter replaced this week. I'll put some drygas in the tank and see if she runs okay.

She is cutting out even at idle after about 30 seconds of running.

I've heard something about an oil pressure sensor that could go bad causing the electric inline fuel pump to not run. I believe the auto choke of the TKS will allow enough fuel in the system to start and run a short amount of time with the fuel provided for startup, but if the fuel pump is inoperative the engine will die after a short while.

Does this ring a bell with anyone?

 

[RMCSURWAR]

Re: Possible Fuel Problem

I wanted to close this thread by informing all that the Marine mechanic found the oil pressure sensor to be bad, and as a safety precaution, does not allow power to the inline electric fuel pump, as the Mercruiser system is designed to reduce the amount of fuel available to an engine running with no oil pressure.

Installed new fuel/oil separator for cause.

New sensor installed and working fine!

 

[MikDee]

Re: Possible Fuel Problem

Wow, interesting, glad to hear!