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Dominick
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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I have a 1997c40elpto that I can't figure out. It runs good

Customer Question

Hey Jeff
I have a 1997c40elpto that I can't figure out. It runs good on a water hose but not at the lake. It will run great for about 3 minutes wide open and then it falls on its face and doesn't want to run after that. And it seems to use an extreme amount of fuel.
Submitted: 1 year ago.
Category: Boat
Expert:  Jeff G. replied 1 year ago.

Sounds like the fuel pump is leaking internally. Your fuel pump is crankcase pulse driven, which means it runs off of pressure from in the engine. If it leaks it will pump fuel into the engine, possibly flooding it and certainly doing what you describe.

The pump comes off with 2 screws, don't take all four off. Then put nuts on the two screws you took off. Once off but still connected to the fuel hoses, squeeze the primer bulb and see if you get any fuel out of the mounting side. If you do the pump is bad and needs rebuilding/

Post back what you find and we'll go from there.

Thanks

Customer: replied 1 year ago.
I rigged up a fuel pump for a lawn mower. It is pumping great. I am pretty good with engines but I can't figure this on out. Does this motor have reeds?
Expert:  Jeff G. replied 1 year ago.

A lawn mower fuel pump? You need to install the proper fuel pump. I know if no lawn mower pump that will work properly.

Yes there are reeds they are on the crankshaft and make up some of the crankshaft bearings.

Customer: replied 1 year ago.
I rebuilt the original fuel pump and it still did the same thing so I put the other fuel pump on just to make sure it wasn't the pump but it did the same thing also. The carbs are clean but one thing different is the oiling system was deleted. I'm not sure if the jets were changed or even if they should have been changed now that the gas is premixed. Should they have been changed?
Expert:  Jeff G. replied 1 year ago.

No the jets should stay the same.

What you can do is to run the motor with a timing light on it. Do this for all the cylinders and see if you have good flashes on all the cylinders. Do this with the lower unit submerged but the boat still on the trailer.

Customer: replied 1 year ago.
Ok. I'll have to did deep and pull out the timing light. Lol
Expert:  Jeff G. replied 1 year ago.

Let me know your results.

Customer: replied 1 year ago.
What would be causing it to use so much fuel?
Expert:  Jeff G. replied 1 year ago.

If the engine is not firing properly, fuel pump leaking, leakage past rings, carb problems will all cause excessive fuel use.

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