1994 omc cobra problems *AGAIN*

[HSBarker81]

What a day....so anyways, some of you may recall my problem with the exhaust hoses melting.<br /><br />I removed the fallen y-pipe flaps from the waterway and things seemed to be fixed. I took the boat out on a sunday and fished all day with no problems. <br /><br />I went out a few days ago and went on a long trip...things seemed fine most of the way. I went to WOT for about 5-6 mins and realized the riser getting hot and the hoses smoking. I let it cool off a bit and then started back on the way home. It ran fine under a cruising speed load. I slowed down a minute and then floored it. The hose seemed to "pop" and then you could hear exhaust really loud. The boat began taking on water so i shut the engine down in hopes of stopping that. It never stopped coming. <br /><br />The host looks like it literally blew apart so i feel like maybe there is a blockage somewhere else in the outdrive or something? I lower the outdrive as much as possible when taking off to help it plane out faster...and i'm wondering if its possible for me to close off the holes in the exhaust bellow enough to cause this? <br /><br />I also noticed that the outdrive had white milky stuff coming out of two small holes on the starboard side and some sort of bearing or seal behind the prop. Any ideas on that as well? <br /><br />Thanks for your help once again. My boating days would be far numbered without you all.<br /><br />-harley

 

[Don S]

Re: 1994 omc cobra problems *AGAIN*

The ONLY reason those exhaust hoses burn is the lack of water. <br />Check your raw water pump, blockage in the intake hose system to the pump, or the manifolds/risers.

 

[Darkhorse1201]

Re: 1994 omc cobra problems *AGAIN*

Hello - IMHO 1st I think you have a blockage problem hence the heating of the hoses and then finally a pop which was probably caused by back pressure. I doubt that lowering the outdrive all the way would keep the exhaust from venting. I sure you blew a hole somewhere in the system thats why you were taking on water. <br />2nd - that mikly white stuff you're seeing is the result of a leak from a seal - probably the seal behind the prop. I sure there are guys with way more experience than I that could give better help but heres mine anyways! Good luck!

 

[HSBarker81]

Re: 1994 omc cobra problems *AGAIN*

thanks guys... <br /><br />don,<br /><br /> i have checked the impeller pump system and it brings the water up pretty well it seems. i'm not sure what is normal pressure, but when i ran the engine with that supply hose off, plenty of water ran through it. the risers could be replaced, but i have tested the flow through them and it seems to flow well also. What about this intake hose system to the pump? <br /><br />sws,<br /><br /> i agree that it is the lower unit oil mixed with water, but i was curious as to whether or not that seal back there would let enough water through for such a thing...i assume it has though, but i will be removing the drive once again and checking all the gaskets i installed. <br /><br />thanks for everything... i know that sometimes i ask questions that i might already know the answers to, i just like to pick at the brains of the more intelligible guys on this board as well as anyone who may have experienced similar problems...<br /><br />-h

 

[cobra 3.0]

Re: 1994 omc cobra problems *AGAIN*

My shaft was broken at the impeller and it did the same thing you describe.

 

[Don S]

Re: 1994 omc cobra problems *AGAIN*

One question NEEDS to be asked here. Since 94 was a change over from the OMC's standard Cobra drive with the raw water pump in the drive to a Volvo/OMC Cobra that didn't have the pump in the drive, but located on the front of the engine and belt drive.<br />Which do you have?

 

[HSBarker81]

Re: 1994 omc cobra problems *AGAIN*

there is a water pump on the engine in the belt drive i think, but i pumped water through the hose (disconnected from the front of the engine) by running the engine (assuming that operates the impeller. I will check on this tomorrow. <br /><br />cobra, <br /><br /> do you mean the impeller shaft was broken or?<br /><br />thanks,<br />harley