Only 4500 RPMs

[nymack66]

Remove the carb cover, move the throttle to the WOT position, verify the butterfiles are fully open. If they are then its another fish to fry ...Maybe prop etc...You need to see at lease 5500 at WOT ....

[bgreene]

Agreed - you need to get at least 5,500 rpm max. If less, something needs attention.

[THEFERMANATOR]

5200-5500 is fine for that engine. The 60 degree engines turn less RPM's than the 90 degree engines do. 5500 is the max WOT RPM's for a 150 IMHO with there smaller porting and carbs. Make sure ytou are getting WOT at the carbs, but do NOT run the engine with the airbox off.

[Skools Out]

those motors the carbs don't open wide open butterflies they go 3/4 factory not sure the reason just letting you know.

[Joker2]

Thanks guys, I will check it out.

[Joker2]

I did check the cable without the engine running, when the throttle was all the way down, I was able to move the linkage at the engine a little ( 1/4" ) more by hand, I don't know what that will translate to as far as getting more RPM's.

[Skools Out]

that's how the 150 and 175 OP came from the factory. have you torn the carbs apart and cleaned?

[Joker2]

The carbs were just done with the rebuild