2205 5.7L Mercruiser will not attain RPM at WOT

[mickey6593]

New 21' 8'' runabout 5.7L mercruiser with 20 hours operation. Have Vengeance 21 pitch prop. Upon wide open throttle will not exceed 3000 rpm's. Any ideas?

 

[Haut Medoc]

Re: 2205 5.7L Mercruiser will not attain RPM at WOT

Welcome to iboats. Are you saying this is new or a re-build? Did it ever get the 4200-4600 rpms that it should?........J

 

[mickey6593]

Re: 2205 5.7L Mercruiser will not attain RPM at WOT

This is a new boat and new motor 2005. Never reached recommended rpm's suggested from the manufacturer which is 4400-4800

 

[Bt Doctur]

Re: 2205 5.7L Mercruiser will not attain RPM at WOT

either its a bit over-propped (14 X 19 P usually)not 21P or the gear ratio in the drive is 1.32(big block) instead of 1.50.engine timing off.

 

[QC]

Re: 2205 5.7L Mercruiser will not attain RPM at WOT

How fast is the boat going? Does it plane? Are you sure the tach is right? IMHO that is too far off for 2 inches of pitch or the gear ratio. Something else is going on here.

 

[waterone1@aol.com]

Re: 2205 5.7L Mercruiser will not attain RPM at WOT

It should be under warranty and the dealer should be anxious to solve this problem now, rather than wait till there is engine damage from "lugging".

 

[Haut Medoc]

Re: 2205 5.7L Mercruiser will not attain RPM at WOT

Brand new? Take it back to the dealer. It is not performing as it should. Oil level is O.K.?...J

 

[mickey6593]

Re: 2205 5.7L Mercruiser will not attain RPM at WOT

The boat plane's fairly fast. Max speed so far is about 44mph and the tach reads about 3600 rpm. Still big problem with the hole shot trying to pull a slalom skier out of the water. With the hole shot, at WOT RPM's increase pretty quick until 3000 then the power just seems to stop increasing as well as the rpm's. Checked all fluids - ok. Not sure of the gear ratio at this point