Fuel problem, please help.

[jjjtronics]

Try this; using a piece of clear fuel line, adapted inline with the fuel line, look for air bubbles running along with the fuel flowing while the engine is at the failing rpm. If you see air bubbles, you have got a vacuum leak somewhere, and that will make your life misserable.
I had a VERY similar problem once, using this clear line method, found a microscopic pin hole in the aluminum fuel pick up tube in the tank.
Remember that thanks to whoever made it a design-rule-law, outboards run on a vacuum- type fuel system all the way up to the pump, which is mounted next to the carbs/injectors, that way there is never-ever pressure on the fuel lines from the tank, which avoids leaks and fire hazards to almost zero. But vacuum leaks are hard to trouble-shoot, but, if the pums are pumping well ( checks with fuel pressure gauge ), and the fuel supply is good ( enough and free of bubbles ) your motor should run good, unless there is a problem with the motor itself.
If you have good fuel supply, I have cleaned my Yamaha`s carbs a couple of times and could help you out on that.

[Blue_Runner]

Thank you JJJ, good ideas.

I've cleaned my carbs with some help from a buddy twice. Might be time to try that agian. I will go ahead and get a carb kit to replace the gaskets. Last time in they were a tad brittle which makes me suspicious.

[nymack66]

BTW where are the pictures ? :)

[Blue_Runner]

My goodness, I'm in crisis mode...my boat is in ICU and all you can think of is pictures! Shame on you!

[Blue_Runner]

Update: I took the boat to a guy down the road who has quite a bit of experience working on outboards. He diagnosed it as have a bad fuel pump (1 of 2). Well this is great news because it is exactly what I suspected.

He is replacing both fuel pumps and I am supposed to be able to pick it up this evening. If I get it in time I'll be off to the lake for a test run. Wish me luck!! I'm ready to get back out there. I haven't put nearly enough hours on it this year.