97 Honda Bf 75 issue

[joelm]

My 97 Honda wont run full throttle all the time. Its starts and runs fine at lower rpm, once I go to to full throttle I'm only getting about 4900 rpm when I used to get 5600 with no issues and its lost it good holeshot. It starts and runs fine but is now starting to almost stall after a few minutes at idle. But the biggest thing I can't understand is one day it will run fine and idle with no issues, run wide open and get on plane perfect then for no reason drop 700 rpm and start running rough again. Primer ball and fuel lines are in good shape, I also have a kicker motor that is running off the same fuel line and pickup with no issues. Fuel is good as I'm using it quite often and also use stabil or sea foam and run atleast 89 or better ocatane. Any thoughts? All responses appreciated!

 

[hondam]

First Honda does recommends against the use of sea foam, its to corrosive, stabil is good though.

How is fuel line routed? You should never T a fuel line. Valves or check valves are ok. I know fuel balls have them built in but tend to be unreliable. When it is not rigged properly you can get air in the fuel causing performance issues.

Another problem is maybe one of the carbs has something in it. These engines run very smooth so sometimes people dont realize its only running on 3 instead of 4.

A quick an easy check would just be buy/borrow a portable fuel tank with its own hose and try it and see if you have any problems. If your problems are gone then you know its in the boat supply. If its not the i take the boat in and have the carbs went though.