Mercury 90 hp issue

[sam blatt]

Hi everyone. I have a 2009 90 hp mercury 2 stroke. While cruising wide open throttle at 5400 rpm, it'll all of sudden drop 10mph and drop to about 2000 rpm. And then after about 20 seconds it'll jump back up to 5400, and then after about 1 minute, it'll drop back down. I'm hoping it might be old fuel, I burned most of it off last time out. I bought star brute star torn enzyme fuel treatment that I'm gonna add to some fresh gas, and I'm gonna take the boat down to the river and just run. Hoping the treatment will clean things up as it runs through. Will this fix the problem? Or is it something bigger? Fuel pump? Fouled spark plug? Any one else have the same problem? Any help would be appreciated. Thanks.

 

[AirForce]

That won't exactly fix your problem. IF you think you have old gas, drain the tank. Also follow this guideline throughly - don't skimp on anything. http://www.bbcboards.net/mercury-3-...ad-here-upgrade-fuel-supply-system-first.html

 

[Mike Clayton]

Not sure you have it fixed but I would change fuel bulb first and go from there, check fuel filter.....

 

[AirForce]

Mike, problem is, if you ONLY change the bulb and your line has deteriorated, then you have problem further down the line and you'd be right back to where you started. Been there, done that (wasting money), if you change everything out, it all ages at the same time and you make it as part of your maintenance schedule

 

[Mike Clayton]

Yep that would be the best thing to do for sure....... although I have had the bulb problem while other components were fine, cheap fix ....
thanks

 

[cq]

I replaced the complete fuel line on a project toon, every part of the external fuel line from fuel tank up to the carburetor was separating inside. Outside of the hose looked great, almost like new.

 

[AirForce]

Yep, that's why you want to replace the whole kit and caboodle, that junk will quickly clog up the fuel pump and if you have an optimax, it will cost a fortune to get it cleaned out.