Need help!!!

[trenedi2002]

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Hey Guys

I recently took on a huge headache. My partner took my boat out 4 years ago over heated it and parked it. I was laid up and never got around to even touching it!! It is a 470 Mercruiser 170 horsepower 3.7 liter 4 cylinder. I just cleaned out all the old oil all the old gas and did a compression check and surprise all cylinders were between 122 and 130. I did drain out alot of water and old oil that looked like cottage cheese but with alot of patience i got it ready to try to fire, and believe it or not It fired right up ( I swear) !!!
and it idols really nice but seems like it knocks at high RPMs but i cant make it leak engine water into the oil it is water pumped in by the outdrive and noone agrees on what the problem is!!!

Please Help!!!

trenedi2002

 

[Bt Doctur]

Re: Need help!!!

leakdown results would be helpful. whats the oil pressure reading , the noise there hot ,cold or both. does it sound like its coming from the upper or lower part of the engine. it the motor timed correctly and is the fuel useable after layup.
scored piston, main or rod bearinng damaged, piston tapping the head.
should pull the head at least to check for any damage.

 

[JustJason]

Re: Need help!!!

when you say it knocks at high rpm... do you mean it's detonating, or more like a rod knocking??
Are you running the engine under load.. or in neutral? If you don't know or can't tell the difference between detonation and rod knock get yourself a mechanics stethoscope and move it around different places on the engine block to try to isolate the noise.

 

[trenedi2002]

Re: Need help!!!

Hey guys thanks for all the help!!! The oil pressure is fine. And i was just running it in neutral my stepdad said it may be a little slap or just no load on it!!! But I have another problem-- I live in Arizona and that boat will overheat everyday if I dont find a 4" heat exchanger, everyone wants a fortune for 1 but I saw a place online that had them for $125 bit I cant find the websits again Im not sure if they were new but they came with a warranty and thats OK by me!!! If anyone knows where I can find 1 at a decent price I would appreciate the help!!!

Thanks again you all are great!!!

Trenedi2002

 

[Bondo]

Re: Need help!!!

Ayuh,.... Did you try San Jaun Engineering,..??