Hot!!!

[RenkenBman]

I have a 1984 20 foot renken with a 120hp 4 cylinder chevy/omc engine. It bucks bad when idling & is fine at higher rpms.Had the boat out this weekend & it ran great threw the harbor, when I got it up to 1/4 throttle it was great anything past that it started to over heat. Seems to be pleanty of water coming out so I don't think its a water pump. Have changed oil, oil filter, gas & gas filters,distribuator cap & plugs. Need help with this, any would be greatly appreciated. Thank you.

 

[Bondo]

Re: Hot!!!

It bucks bad when idling

Ayuh,.... Your Tune Up wasn't very Sucessful...

Change out the Impeller,+ figure out Why it's Skipping....

 

[CharlieB]

Re: Hot!!!

Hopefully it is just time for a new impeller and one of the plug wire is loose, but....

Inspect the spark plugs and look thru the plug holes at the piston domes for any signs of 'steam cleaned' or rust.


You could have;

a. leaking exhaust manifolds

b. leaking head gasket

If the spark plugs are steam cleaned or rusted then first do a cylinder leak down test, remove the T-stat and housing and watch for any bubbles indicating air blowing into the cooling system.

If it passes that then remove the exhaust manifold, plug the water ports and pressure test.