1994 Searay jetboat 90hp

[w3Monkey]

I have a 1994 Searay Sport Jet with the Mercury Force 90 hp 3 cylinder outboard motor

I had this thing running great then had the air/fuel a little fat 2 turns instead of 1 1/2 and ran it hard with four people in the boat (700lbs)

then it died after half and hour and wouldnt restart.

I pulled the plugs and it spun but water started shooting out of the #3 cylinder. (compression: 120, 128, 105 respectively)

after I spun the motor to cough out the water I put the plugs back in and the motor wont spin. (i can hand spin the motor but a brand new battery new relay and new cables arent enough to spin the motor freely. it will spin freely without the pugs in)

heres my questions: is my first step pull the head i should check the head for crack or to see if i blew the head gasket? or should i not bother because the something in the block is jacked?

 

[QBhoy]

Sounds like you still have water in there or your still pulling water in there. Wouldn’t write the engie off just yet. The one that’s down on compression may just be a result of some water remaining in there.
Make sure you defo have all the water out.
Try to turn her over again after making sure and do it out the water and without the engine being able to take in anymore water to see. Only water or other serious mechanical damage will stop her turning over...but you still have fairly decent compression and I would think more than would be expected than if you had and real damage. Could be the head away but I’d maybe expect a lower compression number than what you have. Really need to figure out where the water has come from. You think she might have taken in water by stopping dead too quick and killing engie ? Especially with the boat loaded up ?

 

[w3Monkey]

Thanks QBhoy! I think you are right - I think I sucked water up. I took it out of the water and spun the motor with plugs out until there was no more water coming out. Put the plugs back in and it still wouldn't spin! Its a simple head so I popped it off and tilted the pitch of the motor in hopes of draining any water that slipped past the piston into the power head since there is no oil pan I cant drain it (to my knowledge) I ran the head to a machine shop and they said it wasnt cracked or warped. the machine shop operator said the gasket looked old and that it looked like water had traveled over it. as soon as the replacement gasket arrives i'll put the head back on. for now i sprayed Lucas assembly oil on the cylinders and pistons to discourage rust. Do you know of anyway to drain the power head of a two stroke? If not I'll just put the head back on and see if the motor will cough out any more water then try putting the plugs back in...