OMC 3.0 Overheated now what?

[ojoe86]

Ok sorry guys but I am new to this boating, engine deal. I work for Chrysler but this boat seem like a different animal? Anyways I have a 94 Sun cruiser with the OMC 3.0 gl and this weekend pulling a tube looked down and engine was hot! I shut it off and looked found alt belt broke guessing that also turning the water pump? once i saw that i messed around with a rope on it tried to start and it wouldn't turn over let it cool off about an 1hr and tried again.. turned over couple times and fired up... pulled out in main water way bout 100ft and turned it off.. guy with me said he saw smoke on top of water when it was turning over. i have read through here and know to do at least the belt and thermostat, what about the smoke whats that mean? my boat in trouble? what do i do? please please help!!!!

 

[HT32BSX115]

Re: OMC 3.0 Overheated now what?

Howdy,


It appears you may have a couple of things going on here.....


If your "alt" belt broke, it HAD to be pretty old........they just don't fail for no reason.....


I have to wonder when the raw water pump was replaced last.....


If you had smoke.....it's very likely the rubber hose-coupling from your riser to the "down-pipe" (burning)


You probably have: A failed raw water pump....you probably need to replace your rubber exhaust couplings, You may have a seized circulating pump (can you turn it by hand?) or a bad alternator.....Or the alt belt was just too old and failed all by itself....


If you are capable of working on the engine, get yourself an OEM service manual for that engine. Otherwise it might be a good idea to find yourself a Volvo Penta (or competent OMC) dealer and have them have a look.


Sorry about that,



Rick




You have a lot going on there. A boat is not like a car at all..... With all due respect.....you cannot neglect maintenance for very long and expect it to keep running (like a car)

 

[ojoe86]

Re: OMC 3.0 Overheated now what?

The belt came off because it looks like it rubbed the bottom alt bolt. The guy had the alt adjusted all the way out so it was either really worn or the belt was baddly stretched, no cracks though. Also the little bit of smoke he saw and the reason it wouldn't turn over, could it be because when i saw it was overheated I turn it off while moving at about 3000 rpm and water rushed up in the exaust? I'll check the water pump tonight...

 

[HT32BSX115]

Re: OMC 3.0 Overheated now what?

Also the little bit of smoke he saw and the reason it wouldn't turn over, could it be because when i saw it was overheated I turn it off while moving at about 3000 rpm and water rushed up in the exaust? I'll check the water pump tonight...

Possibly, you might have mistaken steam for smoke but it usually isn't very visible. If you saw smoke around the engine, it could be the rubber parts in the exhaust system burning from a lack of cooling water.


Shutting it off while underway at high speed can cause a lot of damage from a hydrolock and subsequent sudden stoppage of the engine. If this did not happen, you're lucky!


You probably have a severely stretched (or the wrong) alt belt. It needs to be replaced of course, but if you're having an overheat problem, you should probably start at the raw water pump.

If it's a raw water cooled engine and it was operated in salt water you may also have a clogged (with rust) block, manifold and riser...which can contribute to overheating problems...

 

[ojoe86]

Re: OMC 3.0 Overheated now what?

Im gonna replace the belt and see what i get, the smoike he saw could have been steam. It hasn't been giving any overheating problems maybe it'll only be a belt?

 

[Howard Sterndrive]

Re: OMC 3.0 Overheated now what?

Im gonna replace the belt and see what i get, the smoike he saw could have been steam. It hasn't been giving any overheating problems maybe it'll only be a belt?

best plan.

The circulating pump on the engine wasn't turning, so the water around the temp sender would get very hot but if your raw water impeller was still working, (it stirs flow up pretty good in the block all by itself at cruising rpm's) you probably were still cooling the engine marginally, so you probably are ok.

 

[Lodgepole]

Re: OMC 3.0 Overheated now what?

An exhaust flapper that has come apart and fallen down into the exhaust system can also cause some overheating. The flapper is just below the rubber hose that connects the riser to the through transom exhaust pipe. The flapper is designed to stop backwash from entering the engine.

 

[ojoe86]

Re: OMC 3.0 Overheated now what?

Replaced the belt, changed the oil and drove around all day sunday no problems at all!!! Checked the compression after it was warm, 150psi on all cylinders. Also did a leak down test and i am loosing 2-3% out the oil cap (rings) is this normal leakdown?

 

[HT32BSX115]

Re: OMC 3.0 Overheated now what?

150psi is quite normal for that engine....