86 js 300 overheating

[jsride]

i bought a 86 js 300 it hasn't run in about 10 years is what i was told. i checked everything over and found that the impeller housing had a warped stainless steel ring so the impeller wouldn't turn. i machined a plastic ring out and installed i also took the head off and checked the cylinder wall thinking it would be rusted. but was supprised to see that it was in good shape. installed new head gasket took to the lake to try out. well it got up to speed seemed to be about 25 to 30 mph then white smoke came out the exhaust and lost all speed overheated the engine. so i took off the inlet hose and ran hooked to the dock reving up not much pressure but i am not sure how much pressure should be there also no water when i take the hose off the head any ideas on why this is overheating i ran it on a garden hose for 10 minutes ran great also the plastic impeller ring is still in place and still within specs any ideas thanks.

[dsolie]

Re: 86 js 300 overheating

What is your compression? There is a possibility that you poped a cyl.

[jsride]

Re: 86 js 300 overheating

i have 130 psi compression i also removed the exhaust to see if there is any blockage

[K6jet]

Re: 86 js 300 overheating

As for the coolant system, it may be clogged somewhere, possibly, but I think you have other problems. Also, the line coming off the head, I have a similiar one, and a constant strem of water isnt on mine, but rather a strong white water mist.

[jsride]

Re: 86 js 300 overheating

well i removed the jug tonight and found that the crank bearing is bad but could that be my overheating problem well i guess that i will have to shoot for next summer