Lost 500 rpm on Jet! Why?

[Mofish]

I replaced an impeller on a 115 yamaha and lost 500rpm can anyone give me idea to the cause?

Put the same 7 3/8D that it came with and and gaped at 1/32 at the ring. :help:

[weekender]

Its running tighter with better effeciency. Did you buy the boat new or used? Let me guess, your RPM's are lower, but your hole shot and MPH seem to be just as good or better?

[Mofish]

No it takes to much longer to plane and lost top end. Motor running great.

[runaway101]

Yep

[Reel Fun Fish'n]

I'm not a math wiz but. gapped at 1/32 of an inch.
My impellar is gapped at .008 to .010. Thats at the liner.
And did you replace the liner at the same time?

[suckerfish]

Make sure the shoe isn't cocked. The shoe should have a nice flush seat all the way around.

suckerfish

[Keta]

I would guess that the impeler is rubbing on the liner.

[slowbuilder2005]

I'm not a jet expert ...but do these things come with a pitch that you can pick, or are all impellers created equal? The problem sounds a lot like what you get with a prop that's over-pitched for the weight of the boat.

Brian

[Mofish]

Problem fixed> Got a new impeller to replace the new one that I just got and corrected the problem I am back to 5100rpm and it shots out great :wave:.

2 impelllers marked the same 7 3/8D and to diffirent RPMs

My guess is someone goofed up. :eek: