28zx max rpm problems
 

I have a 1998 28zx with twin 350 mags 300hrsp. 2 weeks ago for tickfaw 200 boat ran fine 4 people full of fuel wot 4900 70 mph. Took the boat out last weekend 2 people 3/4 fuel 4400 trying to blow props out 63 mph. Only change was adding 25 gallons of fuel to the existing 50 gallons. Replaced fuel filters and cleaned flame arrestors which were very dirty. Took boat out today Put 28 gallons of fresh fuel non ethenol and still the same problem cannot get the rpms over 4500 and onlt seeing 62-63 mph any suggestions. Thanks in Advance.

Both motors same rpms.

fixx
 

when you cleaned the flame arrestors did you remove them fron the carberator's..if no then now you have to remove the crud from the air bleedes in the body of the carb's.

yes the flame arrestors were removed from the throttle body. The engines are mpi.