06 opti suspected fuel problem

[rsw21282]

I have a 2006 merc optimax 150. until now have had no problems with it. I took the boat out this weekend and the motor ran fairly rough. it had a bit of a problem starting but does start and idles ok for a while but will eventually die at idle. when the motor put into gear it wants to die unless you give it more throttle but will not go past around 1500 rpm, it starts stumbling. I think its a fuel problem, I have fresh gas in it. changed fuel filter and verified the hoses are tight and not coming apart inside. one thing that not sure about, if I give it throttle to point starts to stumble, then pump ball doesn't change at all. and pumped ball with filter off and fuel flows fine. also I have not had any alarms beep.

any suggestions?

Im in process of taking off fuel pump to check diaphragm.

 

[tomibach]

Re: 06 opti suspected fuel problem

been down that road...problems arise with air vs fuel pressure values...fuel pressure should always be 10psi higher than air pressure...on the fuel rails there are 1) tracker valve (easy to replace diaphragm and spring) that monitors fuel/air pressure and on the opposite fuel rail there is an air pressure regulator (big round thingy) almost impossible to replace parts as Merc does not sell it separately...comes as an integral part of the fuel rail assembly...have a shop put their pressure gauge rig on the engine and measure fuel vs air pressure...chances are the problem is with tracker valve (relatively cheap) or air pressure regulator(new fuel rail assembly time)...even small fluctuations of the air pressure can cause major problems with the engine running properly....


After a bit of research...I might have lied...it seems the air pressure regulator may be available separately for your model engine...