3500rpm wall omc260
 

Guys I took my formula out today and hit a wall with the motor... She will only rev to 3500rpm under load. Revs fine not under load and she's only turning a stock 14 1/2 x 19p 3 blade aluminum prop. Its an OMC260 (350sbc) and the boats an 81. help?

What have you done different ? What lead up to this? Need more info.

Absolutely nothing... The only thing is she's running on older fuel. Otherwise stock through and through, though I just went through the outdrive

Check my reply in the Formula owners section...

Check fuel filter, fuel pump, ignition timing, change plugs, cap and rotor, etc...

Timing is set. Plugs wires cap are set, fuel filter is new napa gold and clean with no real debris. Collapsed line maybe? Fuel screens on the tank??

Old fuel? Is it E-10? Have you done your summerization? Check your fuel system (the best way is with a vacuum gauge) , make sure the secondaries open on the carb (check that they are not stuck with the engine not running). Check for full advance on your timing.

Also if it is E-10 pump it out and dispose of it as it is no good! Stabilized or not.

Could also be the ignition coil or the carb. gotta be fuel or spark.

The coils were always prone to going bad and that's an easy swap. They crack and break up right around 3500 rpms.

I'll check for secondaries on the carb. There is no break up in the engine, so I don't think the coil. She runs good all the way too 3500. The only exception is that she bogs if you just slam the throttle, even if she's already on plane. Bogs bad, like threatening to stall...