140 Johnson prop question

[mbecke2]

Just repowered my 17 foot chris craft ski boat. Had a 110 johnson upgraded to 140. The prop on the 140 was a 15 pitch and was only goin about 36mph so I put the prop on from the 110 which is 19 pitch and boat went 42mph. I just bought a brand new 23 pitch prop thinkin I would go about 48mph, and I was a bit dissapointed when I only got 45 mph. Heres my problem: MY TACHOMETER IS BROKE!!!! So should I be happy with 45mph, or can I raise the motor on the transom an inch or two and go a bit faster?? Also when I put it in gear it makes a loud thump and goes about 5mph. Is this prop TOO MUCH pitch, or should I lower the idle?
PS I dont ski with this boat, only fish!!

 

[kenmyfam]

Re: 140 Johnson prop question

I would start with a new tach and work it from there. Sounds like you could have any or all of several issues.

 

[tashasdaddy]

Re: 140 Johnson prop question

sounds as if idle is too high. the idea of different props, is to get the motor turning it's correct wot rpms. speed is not the object.