Problem with Yamaha 115 1998 losing power

[CHEWBAKA1973]

I recently purchased a used 1998 yam 115. It has a 704 con*****er. Today was my second outing using this motor. First outing went perfect that was about two weeks ago.

Today as soon as I put the boat in the water and got on a plane the engine bogged down at approximatly 3000-3500 rpm. Running at 3000 or lower the engine runs fine. No prob starting or running at lower speeds.
My first thought was fuel supply issue.
Anyone have any ideas where to start looking for this issue?

Thx in advance.

[Sequoiha]

sounds like a fuel issue, maybe a fuel water seperator or primary filter.. 3000 is to high for rpm reduction..

[CHEWBAKA1973]

Water separator did not fix my issue. Actually it became worse. The engine stalled at the ramp under no load. I was able to start it and go under way but died even at slow speed. Could a bad primer bulb cause the engine to starve from fuel?
What else could cause the engine not receiving proper fuel?
I dumped out the main engine fuel filter and it did not seem dirty at all.
Any other advice would be greatly appreciated.

[ausnoelm]

you need to start right at the beginning, do you have a manual? if not buy one, try running from a complete remote tank and hose with fresh fuel, remove the plugs and have a good look at them, do they all look the same?, do these simple things, then get back to us, but before you start pulling anything to bits, buy a genuine manual, and read the carb rebuild section.

[CHEWBAKA1973]

Thx for the tips. I was thinking to bypass my in boat tank with and external to verify the problem to beat the motor or fuel supply side. Ill have a look at the plugs. Stay tuned.

[rodbolt17]

why not simply fix the fuel issue before blowing a piston?

clean the carbs,flush the lines, replace the fuel pump and go ahead and replace the water pump kit and t-stats. will take about 5 hours of your time.

[CHEWBAKA1973]

why not simply fix the fuel issue before blowing a piston?

clean the carbs,flush the lines, replace the fuel pump and go ahead and replace the water pump kit and t-stats. will take about 5 hours of your time.

I was trying to find out and fix the simple things before doing complete overhaul of the system. Yesterday the only way I was able to keep the The motor running underload was by priming the primer bulb constantly while running at slow speed.
Also the engine runs fine when it's on the hose Idleing or even at higher RPMs. The only time it seems to have a problem when its under load or in the water.

[CHEWBAKA1973]

Problem fixed. I made sure the tank vent was not obstructed and the primer bulb was primed. Of course the scource of all my problems was an old fuel water sepperator. Runs like a charm. Now waiting for the next problem to occur