vibration and power loss

[swg]

I have a '98 jet omc 115 in my 14' jet boat. I just had the powerhead replaced with a new one. I took it out today to run a few break-in hours according to recommendations keeping revs under 4000 rpm, no extended idling time,etc. I traveled about 4 miles and stopped for a few minutes and after resuming noticed vibration and loss of power at about 2800 rpm. I lowered to about 2500 and limped back home to my dock. I did not notice any excessive smoking, stalling or unusual noises. Does anyone know what this problem could be? I'm taking the boat back to the shop tomorrow.

 

[Bondo]

Re: vibration and power loss

Fouled out a plug,+ lost a cyl.??????

 

[randyc2958]

Re: vibration and power loss

Check the jet pump for any obstruction around the impeller. I have had jet ski's and jet boats and have experniced the same thing.

 

[B_Eager]

Re: vibration and power loss

You could have something caught like a piece of drift wood cuaght between the prop blades. or a leak sucking air into the pump area between the plates.

 

[swg]

Re: vibration and power loss

First of all I appreciate your quick replies. I put the boat in the water just to see if there would be any change in performance and ,lo and behold, it ran out good as if nothing had happened. I took the boat in to the shop and my mechanic told me he would check it out and get back to me. He said by my description it sounded like an impeller problem. I noticed some weed or grass clumps in the area of my run yesterday but didnt notice anything hanging down from the intake area. Anyway I guess i'll find out something tomorrow. Thanks again guys, its good to have some opinions before going to the marine shop.