Sportjet 90

[dwachter]

I have a 1994 Baja Blast with a SportJet 90. Over the years I have had a hard time keeping it running (it is costly)... I have replaced too many parts to list here. I am taking in water in the cylinders and thought it was the exhaust plate gasket so I replaced it (this happened once before) but this time it still took on water in the cylinders. The only other thing this could be is the head gasket (I guess)...I want to run a compression check but the service manual did not list the compression reading for this (it left it out among other things). Any suggestions on what the problem is or what this reading should be?

 

[bomar76]

Re: Sportjet 90

since it's really just a Merc Outboard power head mated to a jet pump, I'd post the problem in the Mrc Outboard section of the forums...as it really doesn't have anything to do with the Baja aspect of the boat.

 

[SpinnerBait_Nut]

Re: Sportjet 90

Welcome to iboats dwachter, as bomar says, let's get this to the Merc/Mariner repair forum.

 

[Capt Ken]

Re: Sportjet 90

Actualy its a Force powerhead and no book will give you numbers for compression. Just a percentage difference between the highest and lowest cylinder. Usually around 10-12% is the max. Be sure your engine isn't dieseling when you shut it down. It could be sucking it back thru the exhaust.