mercury sport jet 120

[Belleville Lake]

We put our Mirage Sugar Sand Mercury sport jet 120 in the lake for the first time this year. Engine kicked over, fired up, and then quit. Pulled the plugs and cylinders were filled with water. Any idea why?

 

[Belleville Lake]

Re: mercury sport jet 120

Brought boat to I-94 Marine in Belleville, pulled engine, looked for crack in exhaust manifold...found noe. Replaced exhaust manifold gasket. Dropped in lake and boat started & ran. Could this bad gasket have been the reason water was in the cylinders?

 

[Belleville Lake]

Re: mercury sport jet 120

Pulled moter from boat, moter was OK. Jet drive froze up, no lube.

 

[ThrashN]

Re: mercury sport jet 120

Brought boat to I-94 Marine in Belleville, pulled engine, looked for crack in exhaust manifold...found noe. Replaced exhaust manifold gasket. Dropped in lake and boat started & ran. Could this bad gasket have been the reason water was in the cylinders?

I have a Sea Rayder with a 120 and it has the same problem. Boat place told me it was from the exhaust manifold gasket.
Still trying to find a way to fix it, I know nothing about boat motors.