Please help!

[sebas54]

Hi,
I have a 22' 1980 aquasport with a 4.3l merc. It had a 15.25 x 15 prop and only ran 26mph at 4700 rpm. I just bought a new prop 16 x 14 and the rpms went up but I lost speed. It ran 24mph at 4800-4900rpms. The boat seemed as if it was going to take off, the bow was high in the air.

I dont have trim tabs but am considering getting them.

Please, what prop size do I need??

 

[steelespike]

Re: Please help!

I believe something is not right.I think speeds should approach 40 with a prop around 17 to 19 " pitch.Your boat is 170 hp and 2,200 lbs.You may want to confirm the motor is sound,good compression, in excellent tune operating on all cylinders.Throttle opening all the way.Bottom is clean prop clean and in excellent shape.

 

[rndn]

Re: Please help!

4800 is the maximum suggested rpm's for your boat. You need to make sure you don't prop it where it will be able to rev beyond 4800.

 

[sebas54]

Re: Please help!

Thanks for all the info.

I have been taking good care of this boat, with regular tune ups. I dont have the compression #'s yet but will get them next week.

Should I go back to 15.25 x 15 prop???


How can I tell if the boat is water logged without cuttung a hole in the floor???


Thanks