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Charles
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3342
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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I have a 1997 250 Yamaha o66 fresh rebuilt power head 8 hrs

Customer Question

I have a 1997 250 Yamaha o66 fresh rebuilt power head 8 hrs on it . cranks runs good but after running it for 25 minutes I turn it off , it will crank over not turn on , but will putter no start . I checked fuel pressure and spark I have both. If I disconnect the hi volume pump it will start for a few seconds until I reconnect pump and then it will run again
Submitted: 4 months ago.
Category: Boat
Customer: replied 4 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Charles replied 4 months ago.

Hello, my name is***** will assist you.

What are you getting for fuel pressure?

Customer: replied 4 months ago.
I don't have that info
Expert:  Charles replied 4 months ago.

Can you test it when cranking the engine?

Customer: replied 4 months ago.
I will but not at this time not close to boat
Expert:  Charles replied 4 months ago.

Thats fine. There are no time limits here. You can rent the gauge from a chain auto parts store. It needs to be able to screw onto a schreader valve.

Customer: replied 4 months ago.
You think it's not holding pressure and if not what pressure should it be
Expert:  Charles replied 4 months ago.

Right now, I am leaning toward flooding when the pump is plugged in. When you ar eat the boat, also remove the plugs to see if they are wet.

Customer: replied 4 months ago.
Local mechanic check it and he told me it was flood the motor then he unplugged the hi volume pump and it crank up and then I plugged the pump backup and it stayed running
Expert:  Charles replied 4 months ago.

A pressure test will tell us much on it.

Customer: replied 4 months ago.
What controls they amount of fuel that goes to the injectors
Expert:  Charles replied 4 months ago.

the pump provide the pressure, the ECU control how long they are open. It there is too much pressure and the ECU if functioning correctly, you will still flood the engine.

Where did the replacement pump come from?

Customer: replied 4 months ago.
Dealer
Expert:  Charles replied 4 months ago.

Do you know the part number from it? On a box or a package?

Customer: replied 4 months ago.
It was replaced about 6 months ago I don't have that info
Expert:  Charles replied 4 months ago.

How long has the engine run badly?

Customer: replied 4 months ago.
Engine runs great the only problem is when I stop after 20 minutes or so and cut it off it will not crank up
Customer: replied 4 months ago.
It starts fine when it's cold
Expert:  Charles replied 4 months ago.

Have the pulse pumps been looked at?

Expert:  Charles replied 4 months ago.

Nodding off here. Im going to log out. Ill be back later today. We can pick it up there.

Customer: replied 4 months ago.
Ok same here
Expert:  Charles replied 4 months ago.

any luck with the pressure tests?

Customer: replied 4 months ago.
30 pounds steady
Customer: replied 4 months ago.
Warmed up and jump to 38
Expert:  Charles replied 4 months ago.

Well that is right on the money. Have you looked at the pulse pumps?

Customer: replied 4 months ago.
No not yet what should I be looking for
Expert:  Charles replied 4 months ago.

remove the two hex head bolts from each pump, leave all hoses attached, then squeeze your primer bulb. Look to see it there is any fuel coming from the hole in the back of them.

Customer: replied 4 months ago.
Ok I'll check tomorrow I'm away from were the boat is
Expert:  Charles replied 4 months ago.

Sounds good.

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