How to check for exhaust leak?

sat1962

Petty Officer 2nd Class
Joined
May 26, 2008
Messages
106
Does anyone know how i can test for exhaust leak I have a 1988 70 johnson new fuel lines, new powerpack, new fuel tank, new fuel pump, cleaned and rebuilt carbs, new head gasket, new intake gasket....... looking over my shoulder so my wife doesn't see all new parts...... and it still sneezes and runs like an anchor! My kayak runs better!

Any help much appreciated..... looking forward to the day I can come back here and say it runs great. :confused:
 

CATransplant

Admiral
Joined
Feb 26, 2005
Messages
6,319
Re: How to check for exhaust leak?

If you suspect that an exhaust leak is choking your outboard out with the hood on it, try running it without the cowling. If things improve, then you should suspect the exhaust leak.

I do note, however, that you don't mention a compression test on this engine. Have you done that?
 

sat1962

Petty Officer 2nd Class
Joined
May 26, 2008
Messages
106
Re: How to check for exhaust leak?

it does run with the hood off
i did a cmpression test couple weeks ago but im going to do one again the one i did was #1-120 #2-119#3-120 how do i check exhaust leak
 

flabum

Chief Petty Officer
Joined
Feb 17, 2007
Messages
567
Re: How to check for exhaust leak?

If it runs good without the hood, then you do have a leak. Two places....

1) The side cover gaskets This should be pretty obvious as there will be a blackened area where the gases are escaping. You can use soapy water to locate the leak with the engine running IN THE WATER. It has to be in the water to create back-pressure.

2) Powerhead base gasket leaking.
 

sat1962

Petty Officer 2nd Class
Joined
May 26, 2008
Messages
106
Re: How to check for exhaust leak?

is there a way to test the powerhead base gasket and how big of job is it to replace it if it is
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: How to check for exhaust leak?

You're going to have a new motor soon, all done with parts replacement. You need to start troubleshooting in a logical way, rather than jumping all around and putting new parts in.
 
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