How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Charles Your Own Question
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3933
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
Type Your Boat Question Here...
Charles is online now
A new question is answered every 9 seconds

I just bought a 1998 mercury 225 efi.0G693556 the first 3

Customer Question

I just bought a 1998 mercury 225 efi.0G693556
the first 3 times on the water it starts and idles great but put in forward the engine dies(as if key is turned off) but doesn't die when shifted to reverse.
I found that trimming the motor level would let me take off . i checked the voltage on the tps and found 3.8 vdc throttle closed and .95 vdc open. I ajusted to the proper .95vdc closed to 3.8vdc open. motor ran great for 15 minutes, then shut down completly. i had to limp to the ramp at just above idle. after getting home, the tps still tested good. help?
Submitted: 1 year ago.
Category: Boat
Expert:  Charles replied 1 year ago.

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

There are a few things to check first. Number one is the compression of the engine, make sure that all 6 cylinders are over 90 PSI and with-in 10% of each other. Make sure that you do have the Champion QL77CC spark plugs installed, this engine does not run well on any other plug. Check the ends of the spark plugs to make sure that they are not overly fouled. Make sure that your battery is staying well above 8V when the engine is running. If you are having to charge it after a day on the water, either the charging system is bad or the battery is.

Let me know what you find out.

Customer: replied 1 year ago.
Not much help😡
Expert:  Charles replied 1 year ago.

What all have you already done, so that I do not have you check something that you already have?