OMC Cobra 4.3 overheating again

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ski_atomic

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Hello everyone, me again??? no wonder, ok i changed the water pump kit (impeller, housing, and gaskets) and there was still no water coming in to cool off the engine but luckily it did not burn anything on the water pump kit, so we decided to put that away and to go directly with the garden hose. now, we thought that the filter in the back of an engine compartment is clogged so we attached the garden hose to the hose that is bringing the raw water into the thermostat housing, and it circulated in a sense that it was shooting out on the stern (backwards) where the impeller is supposed to be. so it fixed the problem of the filter (i guuess) since it got rid off all the rubber pieces from the previous impeller that was burnt. Of course, we changed the thermostat right away and that did not fix the problem, water is not coming to the thermostat housing from the outside at all, its just sitting in the stern drive chamber all filled up to the top. Now, how possible is that it is a water pump that is driven by the belt is at fault? Friend of mine told me that chances of that failing are zero to none, unless it is leaking. It is not leaking, so could it be a failure or no, and are there any other recommendations why it is not bringing up the water to the engine. thanks so much
 

Don S

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Re: OMC Cobra 4.3 overheating again

That belt drive pump is only a circulation pump, and has nothing to do with getting water to the thermostat housing. That is the job of the raw water pump in the drive.<br />If you can't get water to the thermostat housing, the pump is bad, or something is plugged up. Since you have all that impeller remains in there, I would guess it plugs up things. You are just going to have to clean it all out.
 

ski_atomic

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Re: OMC Cobra 4.3 overheating again

Thanks Don, im cleaning them all up right now but it seems like it has a leak on the hose going from outdrive towards the engine compartment, now it does not look like that leak is so major to be causing the entire system not be bringing water to the engine, or im wrong? please help, thanks so much
 

ski_atomic

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Re: OMC Cobra 4.3 overheating again

Also, we brought the hose directly to the thermostat housing but it leaked right next to the engine mount plate on the passenger side, is it supposed to be so? since someone told me it might be a freeze damage, also it does not mix oil and water so i doubt that the block is cracked, do you agree?<br />Thanks again
 

ski_atomic

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Re: OMC Cobra 4.3 overheating again

Little correction, the hose that has the hole is pretty big and ribbed going from outdrive to inside compartment, not the exhaust hose (lower one) but the upper one and has a hole approximately 1 square inch looks like ripped or rubbed against something. it has water streak lines (rust orange color).... please help seems like im almost there.<br />THANKS
 

ski_atomic

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Re: OMC Cobra 4.3 overheating again

That hose seems not to have anything to the with water, it holds shafts (ill change that, but the small hose is leaking water actually the one going into the engine compartment, could that be causing the entire system not to bring any flow to thermostat housing.<br />THanks
 

ski_atomic

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Re: OMC Cobra 4.3 overheating again

people help, anybody knows any good mechanics for OMC in Chicagoland,Northern Illinois, Southern Wisconsin????
 

Boatin Bob

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Re: OMC Cobra 4.3 overheating again

You are on the right track, change that small hose that is leaking and the filter thing you called at the back of the engine is most likely the power steering cooler, these can get clogged restricting water flow as well, the water leaves the outdrive, goes through the cooler and then on to the T-Stat housing. That ribbed hose sounds like it's the u-joint bellows, if it's leaking and the boat was in the water then your gimbal bearing and u-joints are toast, your right it has nothing to do with your water flow problem but needs to fix as well.
 

ski_atomic

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Re: OMC Cobra 4.3 overheating again

Hmm , you guys rule, wish i had 1/16th of your knowledge maybe id be able to do something, well, i took out all the hoses except the one in the outdrive. they have some rust but no clogs so i am going to change them anyways cuz i hate doing a halfass job, so i will keep going till i get it right. now, i took out the power steering cooler (to my knowledge filter but im pretty limited:)) and it seems really good, all the water paths are extremely clean but anyways i cleaned it with power pressure (not direct target but pretty strong). so that seems ok, now, im going to take of that hose in the outdrive but it is pretty anal, so if you guys have any easier way to get around please let me know. Now, once i took off the hoses that go from thermostat housing to manifolds there was a river of water that came out from each, some from manis, some from the hose. is that good or bad?? the water seemed pretty fresh no smell no rust. now probably the most retarded questions: up until now i checked hoses with garden hose water, once i put newones in and fix the u-joint bellows problem should i take it to the river and keep it on the trailer and let it work at idle or do you have any easier solutions since the river is an hour away from me. <br />Now about the u-joint bellows, im not sure when did that happen, yes there are small streak lines of rusty water (so seems like from last year and yes it has been put in the water since. How can i check out if the gimbal bearing and u-joints are toast and how big of a job is to get them done by myself and how much would mechanic charge me (any approximate idea)<br />THANKS GUYS SO MUCH, I almost gave up but i decided to go all the way and now you gave me even more courage to keep going.<br /><br />*hmm one more thing, what is the oil in the power steering cooler and where does it come from and how can i check the level of such.<br /><br />THANKS
 

rizy1976

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May 7, 2006
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Re: OMC Cobra 4.3 overheating again

hi guys. was reading the issue here.. I think ive run into same problem. Was struggling with carb and ran the motor with water hose rigged up and T-Stat housing and burnt out impeller running dry. Just ordered a water pump repair kit. And hoping building new impeller would fix the prob. I did hear some popping sounds last time I ran the engine with dry impeller. Hopefully it was just impeller and nothign else. Engine still runs pretty good after i rebuilt the carb. <br />Any suggestions. I would be following this thread.<br />Thanks guys.
 

Don S

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Re: OMC Cobra 4.3 overheating again

Start a new thread with your question Rox, 2 people asking questions in the same thread is way confusing even if the issues are similar.
 

ski_atomic

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Re: OMC Cobra 4.3 overheating again

ok guys, i got rid off all the hoses and bought brand new ones that i will connect today. The hose that goes from outdrive towards the engine had a hole of approximately 1 inch (burnt or rubbed against something) i have no idea from and against what but i will put a new one in. now, could that be causing the entire system not to bring any flow (i guess it was losing lot of pressure there so...)but im probably wrong. Also, i cant take off my risers, any recommendations, they are literally stuck on manis. i will get new gaskets but how can i take them of without damaging the riser or manifold itself. also can you please tell me some more about the questions i wondered about in my previous post.Thanks guys so much.
 

Boatin Bob

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Re: OMC Cobra 4.3 overheating again

ski...sounds like you may have found your loss of cooling problem with that bad hose. As for the gimbal bearing and u-joints if there was water in there you can bet they are or will be soon no good anymore. When you remove the outdrive spin the gimbal and see if it feels rough but I would recommend changing anyway and the u-joints or you'll be back here asking about the noises your hearing especially when turning and triming the drive ;)
 

ski_atomic

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Re: OMC Cobra 4.3 overheating again

hahaha :) You guys are awesome, well im kinda getting hooked on this thing cuz every time i learn something new, now the first thing i do at work is iboats.com :) but its great, does not hurt to know and is really practical and no B.S. thanks to you guys. i will probably end up taking it to mechanic for the outdrive since i dont have tools (lift) to take down entire outdrive and seems bit complicated taking off all the trim details, cables, hoses and such so ill probably end up taking it to the shop for that (any idea what price will i be looking at)??? kinda silly question but my financial situation is not ready to suffer a 1000 or more so.... <br />Thanks Bob so much, you and DonS are the main assets to all of us.
 

Carlos Moreno

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Jan 25, 2009
Messages
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Re: OMC Cobra 4.3 overheating again

hi all of you.

I have a problem with my 4.3 omc cobra. the impeller is new, and so the hoses.
Wen I start the engine, the manifolds get overheat, burning the exhaust hoses.

sombady knows what i need to do ?
 

Don S

Honorary Moderator Emeritus
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Messages
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Re: OMC Cobra 4.3 overheating again

Welcome to iboats Carlos.
If you have a question, start your own thread, do not stick your question at the bottom of a 2 year old thread where no one will see it after a rely or 2.
 
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