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 Joe Your Own Question
Joe, Marine Mechanic
Category: Boat
Satisfied Customers: 7121
Experience:  ASE, electronics, Marine mechanical and electronics, pwc, wiring, all around repair tech,
Type Your Boat Question Here...
Joe is online now
A new question is answered every 9 seconds

Yamaha 70HP oil injection engine. This engine has set a

Customer Question

Yamaha 70HP oil injection engine. This engine has set for about a year. Prior to that it ran perfectly. Boat is a Bass Tracker 19 footer. Always before the engine would turn up to 5800 RPM. Now it will only run up to about 3800 RPM at about 1/2 throttle. Throttle above that does nothing. Examining the carbs with the air filter off all three are opening full. We cleaned the on the engine fuel filter replaced the inline gas filter with a new one. Replaced the spark plugs. The Clear Inline Fuel filter never fills with Gas. Actually it shows only a small amount of gas in the filter. The fuel is clean and new. Boat Gas only. Is it possible that the squeeze bulb is restricting the fuel? Is is possible the fuel pump is not sucking enough fuel? Is it a Carb issue? The Engine has always been run until it ran out of gas by removing the fuel line from the tank. Engine run until it quit. So any ideas where to look for the problem?
John Goller
Submitted: 6 months ago.
Category: Boat
Expert:  Joe replied 6 months ago.

Hello John,

Thank you for allowing me to assist you, my name is Joe and I will be happy to assist you with your concern today.

Using an external portable tank connect to the motor and see if the problem is corrected, if so then you know you will have a problem between the tank and the motor, a bad ball will not correctly prime/purge, there can also be leaks allowing it to pull air but not spit fuel, there is also a valve but before getting to that please remove the fuel cap and see if the problem corrects, if so then check your vent screen on the side of the hull as wasps and other things are known to clog them, corrosion can also take over and block off the vent opening.

Please proceed with that and let me know your findings.

Thank you!
- Joe

Please rate my answer when ready. Bonuses are appreciated.
If for any reason you are not satisfied please reply back to me for further assistance to which I will be glad to help you. If you have any problems for any reason please reply back and let me know.
Thanks again for using justanswer and have a great day!

If you need any further assistance you can reply back at any time for my help.
I'd be happy to answer any other questions you have even if not related.

Related Boat Questions