Quick Exaust Manifold Question

[alindquist]

1999 Volvo Penta 7.4 GiPWTR
Serial # 4110176452

On the exhaust manifold, should there be a clear path from where the water hose attaches in the front the manifold to the freeze plug on the back of the manifold? i.e. if I stick a wire in the front should it freely come out the back (where the freeze plug is/was)?

Thanks,
Aaron

 

[Bondo]

Re: Quick Exaust Manifold Question

i.e. if I stick a wire in the front should it freely come out the back (where the freeze plug is/was)?

Ayuh,... Probably Not....

There's the inner structure,+ the inner exhaust passages in there...

 

[HT32BSX115]

Re: Quick Exaust Manifold Question

Howdy,

On some exhaust manifolds (OMC 460 and others) you can actually see all the way thru from the front hose connection to the back because they're aligned and there's no internal structure blocking the "view".

Yours may not be constructed that way.


On the other hand, if your engine is raw water cooled and it's been run in salt all it's life, (1999-now)

You may be running on borrowed time.

If you're trying to determine whether you need to replace your manifolds by poking a wire thru them, and/or you're attempting to determine if they're clogged and it's beginning to overheat........and you have not removed your risers and inspected ......


It's time to pull the whole mess off and apart and look very closely.




Cheers,


Rick

 

[alindquist]

Re: Quick Exaust Manifold Question

Risers and manifolds were replaced last year. The Manual says to clean the passageway with a wire that why I'm wondering if the wire should go all the way through. Anybody have any knowledge of this manifold?
http://www.marinepartsexpress.com/vp_sch_fs.html
Part #9 - The tube below the exaust ports.

 

[Don S]

Re: Quick Exaust Manifold Question

The wire wasn't meant to go all the way through, just enough to make sure there is not rust or anything blocking the water from running out the back plug. Note, it is NOT a freeze plug, it's a threaded pipe plug. If you did remove the elbow fitting from the front of the manifold, you could see all the way through. It's a tube cast on the bottom of the manifold. Exactly like the OMC manifolds were.

 

[alindquist]

Re: Quick Exaust Manifold Question

Thanks Don. There isn't an "elbow" fitting on the front or the back, I can get a wire / coat hanger about 3/4 of the way through from either end then it hangs up. I'm thinking it's because the wire gets bent inside or caught on something. Just to clarify, it should be open all the way through correct.

 

[Don S]

Re: Quick Exaust Manifold Question

You do realize, a picture can be worth a 1000 words, and it would show us what your manifold was built like. If you can go 3/4 of the way through from each end it sounds like it's just hanging up on a port or someting because of the way the coat hanger is bent. But I'm not there, and can't feel or see it, so won't say that as pure fact, just my WAG from 3000 miles away.