OMC Over Heating

samm835

samm835

Chief Petty Officer
Joined
Dec 12, 2006
Messages
575
I have a 3.0 OMC/Cobra (1994), yesterday I hooked the boat up to the hose to run for a short while. I noticed the other day on the lake the temp was rising some as we took the boat out of the water, so I hooked it up to the hose to see if it happened again. It was rising, but nothing dramtic, what could cause the temp rising? I also noticed while on the muffs, water wasn't coming out of the prop but it seems to be taking water in and to the motor....is this normal? My main questions are 1) what are the main causes for engine temp rising 2) Is water suppose to come out the prop? Thanks
 
Boatin Bob

Boatin Bob

Lieutenant Commander
Joined
Sep 24, 2001
Messages
1,858
Re: OMC Over Heating

Pretty sure that year/model has an engine mounted belt driven raw water pump, when was the last time the impeller was changed?
 
D

dasnively

Cadet
Joined
Apr 4, 2008
Messages
16
Re: OMC Over Heating

If you find pieces of the impeller missing, you need to figure out where they went. I found pieces of the old impeller blocking the inlet of the waterneck on the motor. (Previous owner had an overheating problem.)
 
samm835

samm835

Chief Petty Officer
Joined
Dec 12, 2006
Messages
575
Re: OMC Over Heating

The impeller hasn't been replaced since I have owned it(less than 6mths), the prior owner stated the drive was rebuilt 1.5 yrs ago and thats all I know. It sounds like I am going to get my first lesson on changing impellers 101 in the next couple of weeks, or pay the mechanic to do it for me. If this is what it is, is this easy or a hard task for the average joe? Thanks
 
D

dasnively

Cadet
Joined
Apr 4, 2008
Messages
16
Re: OMC Over Heating

Is your impeller pulley driven or in the outdrive? I am not as familiar with the 3.0. My 4.3 is mounted to the front pulley of the crankshaft which makes for a very simple change. My buddy has a 3.0 and he was able to change it without a problem. My Seloc book shows a pulley driven pump on the 1994.
 
samm835

samm835

Chief Petty Officer
Joined
Dec 12, 2006
Messages
575
Re: OMC Over Heating

To be honest I don't know, I believe it is pully drive. All I know is there is a pulley/belt on the front portion of the motor.(god I sound like an idiot) I am not sure what all is hooked up to the pulley.
 
D

dasnively

Cadet
Joined
Apr 4, 2008
Messages
16
Re: OMC Over Heating

The raw water pum has two hoses. One goes behind the motor to the transom which picks up the water from the outdrive. The other hose feeds the cooling water to the engine (usually going into the water neck).
 
samm835

samm835

Chief Petty Officer
Joined
Dec 12, 2006
Messages
575
Re: OMC Over Heating

Well tonight I will check to make sure all hoses are hooked up and are complete. I might try to see if I can find a diagram online to show me where my impeller is so I have a better understanding. Well I talked with a couple of friends of friends, and they gave me a local guy (shade tree) that will replace my water impeller on my drive for $250.00.......and do a once over on it. So I am going to go ahead and do that since it should be done anyway. Thanks for the quick help any other ideas I would appreciate it. I think I will be near you next month at a convention at Amelia Island end of next month, maybe I will drop it off to you and see if you can fix it for me...ha ha just kidding thanks for the help!
 
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