Evinrude 7.5hp E8RCSS Low power at high throttle settings

[F16pilotjd]

Installed an old 8hp on my fishing boat and it started right up with fresh gas. Idled great and ran great in the test bath. Brought it out on the water and initially ran great. However, after about 5 min it began to loose power even though it seemed to be running good. Low speed idle nice. Just will no longer get 14ft aluminum sea nymph on plane.
Do you guys have anything I can try? Thinking of replacing plugs and cleaning carb but would like to know if anyone else has a better solution. New to the site and thanks in advance.

 

[racerone]

Could be overheating or running on one cylinder.----Step #1 is a compression test.----If good a spark test.-----Look at water pump impeller.

 

[F16pilotjd]

Could be overheating or running on one cylinder.----Step #1 is a compression test.----If good a spark test.-----Look at water pump impeller.

Ok. Good to know. Nice stream of water coming out of discharge though.

 

[racerone]

Sorry----I guess I missed the water pump stream in post #1.

 

[F16pilotjd]

Sorry----I guess I missed the water pump stream in post #1.

No. I didn’t include. Sorry would be helpful information that I left out. I am a Rookie here

 

[oldboat1]

The high speed jet is a likely culprit. It's screwed into the underside of the tube that runs from the carb bowl to the top of the carb. If you remove the carb from the motor and drop the bowl, you will see the brass jet. Spray it out with carb spray, using the plastic nozzle. You should see the fuel spraying into the throat of the carb.

 

[F16pilotjd]

The high speed jet is a likely culprit. It's screwed into the underside of the tube that runs from the carb bowl to the top of the carb. If you remove the carb from the motor and drop the bowl, you will see the brass jet. Spray it out with carb spray, using the plastic nozzle. You should see the fuel spraying into the throat of the carb.

 

[F16pilotjd]

Thank you very much. I don’t know how long it has been sitting so I ordered a carb rebuild with float and new plugs but will try this fix prior to going through the complete rebuild. Thanks again and anything else you can think of will be helpful.