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40hp Mariner low on power leaking exaust

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Dougan

New member
I have a 40hp Outboard that is very low on power when under load.It will idle and rev out of gear as smooth as always.

I have noticed two things wrong. One is low water pressure, so I replaced the impeller. That did nothing.

The other was an exhaust leak below the motor housing itself. It blows exhaust and water out pretty heavily. There are two bolts going front to back on the lower unit. They have bushings around them that are blown out.

You can get a general idea where it is coming from in this picture.

photo(2).jpg


Is this my problem?

If so what is involved in fixing it.

I have found nothing at all throughout this site or anywhere else for that matter.

I think I am using the wrong words to describe the part that leaking...

Any help would e greatly appreciated!

Thank you!
 
How did the pick up tube line up when water pump was replace mabe corroded i would check thermostat if stuck open may bring down pressure is engine heating up with low pressure?? Low in pwr issue check spark c if firing on all cyl
 
What year is this motor?
Have you checked compression? Spark?? Spark plug condition?? Do any plugs look really clean compared to others.
 
Plugs looked relatively similar to one another.

Compression test was good.

Still thinking its the exhaust leak thats causing it. But not sure if the bushings I mentioned above could have the effect.

Picture is sideways, but you can see the bushing I am referring to.
photo.JPG
 
I would guess that your exhaust found it's way out through the mount bushing. It must be leaking some where. You'll probibly have to pull the power head to find it. If you do, you may as well start looking for a base gasket and exhaust tube gaskets and seals. Find a manual before you do anything.
 
Thank you for the help. Good question as to why it is down on power.

A guy at the local marina suggested it may be seizing due to overheating. I am going to check the thermostat in hope that it is sticking. Really hoping not to have to pull the power head.

Another thought, perhaps its low on power because the exhaust leak is causing the reeds to function improperly...?
 
Not that. It may be cooking itself, however--that would also expalin the exhaust leak (caused by a burnt rubber seal).

Jeff
 
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