omc 2.3 overheating

[HopinImFloatin]

hi, im looking at a friends boat that is overheating. i dont know the exacts of the boat right now but it it is mid 80's early 90's phantom with a 2.3 omc, cobra outdrive. he is having trouble with it overheating and has so far pulled the raw water hose to the t-stat housing and has good flow to it. he replaced the t-stat. with an infared thermometer the manifold is reading around 200 degrees and the engine also. it was suggested to him that possibly the manifold or riser is clogged with rust. is this the next place to look? i may go and look at it tomorrow and i would like to go armed with as much info as possible so i know what im looking at/for. i believe he said there was some debris in the t-stat housing but not much, anywhere else an old impeller could get lodged after the t-stat housing? i assume that i could pull the hose to the manifold and see if i have good flow there and if i do then removal of the riser would be next in line. does this sound correct, not really familiar with this engine...at all but i am a mechanic and do have somewhat of a clue. i realize that more specifics about the boat and motor would help but this is all i have right now. also, if it does turn out to be a restricted riser is it at all recommended to try to clean it or is this strictly a replace only at this point. if it matters its not used in salt water and dont believe it ever has been. thanks in advance and have a good independence day all

 

[Bulbash]

Re: omc 2.3 overheating

Could be the waterpump at the engine is probably gone.... Not sure how to test it... I would really doubt that manifold would be cloged, as there more than one passage, it would probably crack and leak before it would get clogged unless you are running in salt water.

 

[HopinImFloatin]

Re: omc 2.3 overheating

I misunderstood where the t-stat was located on this engine, its right on the exhaust manifold. He said there was good flow to that point so its looking like it has to be the exhaust manifold at this point. He has another parts boat and showed me the manifold off that one, has some pretty small water passages, he will be taking off the elbow this weekend and inspecting. I cant seem to find much info for this engine, i realize its obsolete but still. Having not much luck searching this forum with the search engine. I must be doing something wrong

 

[Bulbash]

Re: omc 2.3 overheating

misunderstood where the t-stat was located on this engine, its right on the exhaust manifold. He said there was good flow to that point so its looking like it has to be the exhaust manifold at this point. He has another parts boat and showed me the manifold off that one, has some pretty small water passages,

It is not the same system as in the car engine... So I do not think you are looking in the right spot for your problem... I have exactly the same engine and know exactly where the thermostat is... You can remove the manifold and see if it is clogged, but I can bet you it will not be clogged...

 

[HopinImFloatin]

Re: omc 2.3 overheating

thanks and you are right,it wasn't the manifold. He took off the t-stat housing again and found a blockage from an old impeller. Says it no longer overheats. Hopefully no other damage was done