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
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3343
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
67216606
Type Your Boat Question Here...
Charles is online now
A new question is answered every 9 seconds

I have a 2001 Yamaha F115 when the engine is cold it goes really

Customer Question

I have a 2001 Yamaha F115 when the engine is cold it goes really well I have a problem without power as soon as it warms lacks power at 4000 rpm it not turn out well. If I throttled to 3000 rpm it runs well mas does not have much power as when it is cold .. I change the spark plug, fuel filter, gasoline full etc. I have the same problem . Rhe moter start very well and run fine in the trottle
Submitted: 1 year ago.
Category: Boat
Expert:  Charles replied 1 year ago.
Hello, my name is***** you for allowing me to assist you today.
You will need to check the ignition when the engine is warm. Use a timing light and just watch the spark on all 4 cylinders to make sure that there is no gaps in the flash.
Test the fuel pressure as well. It should be mid 30's at idle and over 40 PSI when above 1500 RPM.
If those are good, do a compression test on the engine both cold and warm. Let me know what you find out.

Related Boat Questions