Replaced powerhead earlier this year with a brand new powerhead.

Prior to replacing my motor was burning a ton of oil and i was losing power as plugs fouled. I could replace plugs and immediately have my power back.

Running a 250 SHO on a 22' Skeeter CC. I could easily run 55 mph and if i trimmed it just right would max out at 57-58 mph @ 6200 rpms. Even when motor was running horribly, i could achieve these rpms and speeds until plugs fouled.


After replacing powerhead my max rpms are in the 5700-5800 range. My top in speed is 52-53 mph and thats carefully finding the sweet spot between too much trim and too little trim.

Still running the exact same prop.

I completed the break in period as instructed and when i got to the stage where i could run full throttle for short periods of time i immediately noticed loss of power.

I contacted the mechanic and he stated i needed to wait until i got around 40 hours onnthe motor before being.concerned. Well 30 hours and a service.came.and went and now i have around 50 hours and brand new.spark plugs and nothing has changed. Barely.get it to 50 mph with half.trim and can sometimes hit 52 or 53 trying to find the sweet spot.

Any clue on why a new 2019 powerhead would have less power than my original 2013 powerhead?

Is this a new factory OEM full powerhead? If so I would consider contacting Yamaha directly.

If your tach is correct, you were running the old power head 200 RPM above WOT specification (6000 RPM).

Check your throttle linkage adjustment under the cowl to see if your hitting the WOT stop on the throttle body when throttle in full forward position. It may have not been checked/adjusted when new power head installed.

Hope this helps.

Check the throttle cable adjustment, make sure its opening fully.

Rev limiter is usually set at 6150 RPMS from factory

maybe pull the pugs and have a look see, the mechanic may have added some oil to your gas to make sure you didnt cook the motor,.
yes I know its fuel injected, but sometimes adding some oil to the fuel during break in is done. when I bought my 115 yamaha, brand new, the mechanic told me he added a little 2 cycle oil to the fuel for break in. it is an oil injected motor.

It's a 4 stroke motor

If I read your post correctly, you are stating that it is a "new" 2019. Is it a factory fresh 2019 powerhead or a rebuilt 2019 powerhead? If rebuilt could be the tolerances on the rebuild are not to original specs.