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OMC 3.0 liter Exhaust hose

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way2buzy

New member
My engine has blown a brand new exhaust hose, (the one attached to the exhaust manifold riser). Any help on diagnosis would be appreciated!
 
how blown, did it burn through, did it blow off the lower riser?? if burnt water problem in your seawater line, blown off look for the exhaust flap plugging your exhaust down in the gimble
 
it melted. You have an issue with your flow of raw water through the engine.

is this happening in the lake? or in the driveway on muffs?
 
sounds like you need to change your raw water impeller and check exhaust system (riser/manifold) for rust and scale buildup that is impeding water flow out the exhaust.
A good flow of water must mix with the exhaust to prevent the hose melting.
 
hystat said:
sounds like you need to change your raw water impeller and check exhaust system (riser/manifold) for rust and scale buildup that is impeding water flow out the exhaust.
A good flow of water must mix with the exhaust to prevent the hose melting.
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Riser and manifold are clean. I have a dumb question though. Is the fresh water impeller in the lower unit, and is there a way to know if it is working without taking everything apart?
 
omc impellers are in the upper - you haven't said what kind of drive you have, or i missed it.

Get a factory service manual if you are going to maintain the boat yourself (ebay)
 
Cobras are very easy to service - the impeller is under the cover that comes off the upper. no need to remove the drive or lower unit.
 
Fill out the profile,location? You might be close to someone who can help?? The hose from the drive to the thermo housing. Put the boat in the water.Remove the hose and see how much water is pumping. It should be a LOT!! But first remove the cover on the top of the drive.Check the impeller. Any pieces missing? Wore or burnt? The riser make sure it's not clogged. The end plate on the manifold,remove it and check for gunk. The hose fitting,apply water there and see if it flows easy? It should have no restricions.
 
Check your t-stat.

See you have good water coming into the engine ? If yes then the t-stat might be frozen closed.

The elbow is allowing flow ? Then maybe the flapper fell down and is blocking the exhaust . Fish it out don't replace it.

Your temp gauge is not warning you of a overheat condition ?
 
Master mechanic said:
Check your t-stat.

See you have good water coming into the engine ? If yes then the t-stat might be frozen closed.

The elbow is allowing flow ? Then maybe the flapper fell down and is blocking the exhaust . Fish it out don't replace it.

Your temp gauge is not warning you of a overheat condition ?
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The temp gauge will eventually get up to 160-180 but it took a bit.

What should I use to see if there may be an old flapper in the exhaust? When I put the new hose on, I noticed the flapper in there was burned pretty bad and replaced it. But I don't know what if anything has been checked in the past.


Thanks for the info!
 
I have seen the remains of a flapper just the metal make it all the way to the tru hole on the prop.

I have seen them blocking the drive exhaust at the drive and just inside the exhaust pipe in the transom.

If you don't visually inspect the exhaust all the way from the elbow to the drive then you will never know it can lodge anywhere.
 
Master mechanic said:
I have seen the remains of a flapper just the metal make it all the way to the tru hole on the prop.

I have seen them blocking the drive exhaust at the drive and just inside the exhaust pipe in the transom.

If you don't visually inspect the exhaust all the way from the elbow to the drive then you will never know it can lodge anywhere.
Click to expand...


I can not make out where that exhaut tube attaches or where to inspect to find if there are pieces lodged in there. On this particular issue I may be in over my head. The t-stat, riser and hose and exhaust flap were and even the impeller weren't all that difficult, but the actual exhausting is leaving me scratching my head
 
Now we need the year and model#s. The Cobra drive and the older drives are way different. Always include them when asking for help.
 
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