Testing an Exhaust Manifold..??

frustratedboater

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Greetings,
I have a chevy 350 in a Mastercraft American Skier (don't ask..) and I'm not sure how to test the exhaust manifold to see if it is good. I have it off the engine due to very little water coming out the port exhaust flapper and I wanted to inspect it. I've checked the water circulator pump impeller as well and it seems to be good. The boat has a thru-hull water pickup. I have excessive rust build up inside the thermostat neck (where all the hoses connect to) and it is a posibility that the water is being 'favored' to the starboard exhaust side, but can't really look inside of it. There is rust swelling in the smaller hose tubes but can see through it.

Having the manifold off, can I test it to see whether or not if is the issue and rule it out?

~FB~
 

Bondo

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Re: Testing an Exhaust Manifold..??

Ayuh,.. Pull the Riser off the Manifold, that's where they plug up, right at the transition...
And, the gasket faces are where they Rot out 1st...
 

Fishermark

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Re: Testing an Exhaust Manifold..??

Not sure what you have beyond it being a Chevy 350, but one of the members, Bubba, has posted a good set of instructions to check the manifolds: Checking manifolds
 

frustratedboater

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Re: Testing an Exhaust Manifold..??

Thanks for the heads up on the post. It's a PCM manifold--exterior looks great, but I'm assuming here that it is close to the origional. I did pull the riser off last season and the ports weren't exactly closed or rusted shut, but there was a significant amount swelling all around. Chould be it?! I'll run the tests and see what's up.

With my riser still attached, I'm wondering if I can run water through it to see the volume of flow out the riser--perhaps it is the riser restricting the flow, or should it matter?
I appreciate it,

~FB~
 

frustratedboater

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Re: Testing an Exhaust Manifold..??

btdoctur- very interesting article and explains alot and thanks for sending the link. I'm not an expert on exhaust man's, but that helped to see the design and true function of a riser.

Q- Could I attach a hose to the water inlet side of the manifold, with the riser on, run garden hose water through it to see how much rust restriction I may have out the riser? Any way to clear that out if there was?

~FB~
 

Bondo

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Re: Testing an Exhaust Manifold..??

Q- Could I attach a hose to the water inlet side of the manifold, with the riser on, run garden hose water through it to see how much rust restriction I may have out the riser? Any way to clear that out if there was?

Ayuh,... I suppose you Could, but it won't Tell you anything...
Pull the riser Off the manifold,+ Look...

If they're crusty,... Replacement is the Fix...
'cause, All that Crustiness, Used to be solid Cast Iron...

That means your motor is on Borrowed Time...
 

frustratedboater

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Re: Testing an Exhaust Manifold..??

Ayuh,... I suppose you Could, but it won't Tell you anything...
Pull the riser Off the manifold,+ Look...

If they're crusty,... Replacement is the Fix...
'cause, All that Crustiness, Used to be solid Cast Iron...

That means your motor is on Borrowed Time...

I pulled the whole shootin' match off and really my point was to see how much water is coming out the riser before it goes out the pipe. My left-side, while running from the hose, just trickles out, and the right is cold to the touch and pours out. I know I should replace them but need to see if that's the issue.
 

Bondo

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Re: Testing an Exhaust Manifold..??

My left-side, while running from the hose, just trickles out,

Ayuh,... Now ya Know....;)
 
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