Optimax 135 breaking up

[Pfeff77]

I am stumped, 2003 135 optimax 25hrs. Don't rev past 3k. Motor breaks up. Replaced everything imaginable. Fuel pumps, coils, injectors, throttle position sensor etc. Mercury tech hooked to computer, showed 100% power. No audible alarms either. Motor sat for 12 yrs in storage. Any help would be appreciated greatly.

 

[Chris1956]

My neighbor had something similar on his Optimax. I did not do the repair, but they way it was explained to me was that a valve needs to open to supply fuel to the motor. This valve is electric and bypasses the boost fuel pump, allowing fuel directly to the main fuel pump. Apparently the mechanic inadvertently bent a pin in the connector, disabling the valve.

 

[Chigwalla]

How do the spark plugs look ?
Presumably the Merc tech checked air and fuel pressures while the problem was happening ?

 

[p2images]

I had the very same problem this afternoon.as soon as I push the throttle forward to get on plane she dies sputters and runs like crap until the throttle was returned to slow. I have a "98" 135 optimax I suspect it is fuel related. As I just re powered and added a 6 gallon tank with a vapor regulator in line temporarily until I clean the old fuel tank.

 

[Pfeff77]

Mercury tech has motor at 100% power. No alarms. New no plugs also. All fuel and air pressures are on point

 

[ajgraz]

Does that mean it's fixed, or that the problem persists and is as yet unexplained?

(BTW, what does "motor breaks up" mean, exactly?)

 

[Pfeff77]

Not fixed, motor is now off boat. It will not run above 2700 rpm. It starts to run as if I were in safe mode. It vibrates like crazy than stalls. Mercury tech is completely stumped. He shut down each individual cylinder with his computer and it did what it was supposed to do. This boat sat in a climate controlled storage facility for 11 yrs. The motor has 26.5 hrs on it. It has never been run past 4K rpm.

 

[Faztbullet]

I would take a hard look at air compressor and tracker valves. The fuel rails may be bad/clogged.