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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3976
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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We have a Mercury2001 75hp Tracker outboard. After running

Customer Question

We have a Mercury2001 75hp Tracker outboard. After running at high revs for a while the engine dies down to idle. I move the throttle down & back up and revs come back up. What's the problem?
Submitted: 2 years ago.
Category: Boat
Expert:  Charles replied 2 years ago.

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

What RPM are you running when the motor slows down?

does your alarm system work in the boat?

Do you need to stop and restart the engine, or use the primer bulb or anything to get it going again?

Customer: replied 2 years ago.
About 4000 rpm can run at 5200 all day. Alarm system works for oil injection. Will also cut out at other rpms.
Normally don't have to stop & restart. When it's dying, if we pump the primer bulb, it will come back. If it does cut out completely, it's normally easy to restart.
Expert:  Charles replied 2 years ago.

Have you replaced the primer bulb with a good quality one?

Can you check the fuel pump?

Customer: replied 2 years ago.
No, haven't replaced anything as yet. What am I checking on the fuel pump? where is the fuel pump located?
Remember that it runs ok until the engine gets to full operating temp. Then it will start dying at higher revs. Normally before, it would run at 5200 rpm all day.
Expert:  Charles replied 2 years ago.

On the fuel pump you would be looking at the check valves to see if they are still seating. The kit to rebuild it is only $25, so not a bad investment in the long run. The part number for it is 857005A 1.

Would you also please post the serial number of the engine, I need to look at a diagram from it.

Customer: replied 2 years ago.
I still have to locate the fuel pum right now so I will have to get back to you on this. I will get the serial # ***** the engine in the morning.
Expert:  Charles replied 2 years ago.

Sorry, the fuel pump is square and bolted to the left side of the engine. Follow the main fuel line from the cowling and it will go straight to it. About 2" square.

Customer: replied 2 years ago.
Engine serial # ***** OT332219
Expert:  Charles replied 2 years ago.

Thanks. Do you also have a multimeter to do some electrical testing?

Customer: replied 2 years ago.
what are you thinking of?
Expert:  Charles replied 2 years ago.

After you check on the fuel pump, we may need to look at the stator or the trigger.

Customer: replied 2 years ago.
We already ordered the diaphragm kit so we should go there first right?
Expert:  Charles replied 2 years ago.

Yes. That is where I would go in the shop. Since you can squeeze the primer bulb and get the motor to stay running, that is an indication of a weak pump.

Customer: replied 2 years ago.
We haven't had a chance to fit the repair kit yet Charles, but hopefully in the next week or so.
Will let you know,
Expert:  Charles replied 2 years ago.

No worries. Just reply back after you have a chance to get it done.