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View Full Version : How hot should manifolds/risers be?


ProStar Slalom
07-03-2012, 02:36 PM
Fellas,

'84 PCM 351. I put new exhaust manifolds on last weekend since one had been JB welded by the previous owner and was starting to leak. Risers looked fine so I kept the old risers and installed new manifold and riser gaskets. Running fine with no leaks and normal engine temp.

My question is how hot should the manifolds and risers feel? When we ran the boat Sunday my wife noticed a smell while I was skiing. Everything looks fine but the manifolds and risers seem pretty warm. What is normal....should they be warm to the touch, hot to the touch, or too hot to touch? There shouldn't be anything blocking normal water flow but I never paid much attention to their temp prior to the swap so I don't know what normal feels like.

Thanks for the help

Cloaked
07-03-2012, 03:30 PM
Fellas,

'84 PCM 351. I put new exhaust manifolds on last weekend since one had been JB welded by the previous owner and was starting to leak. Risers looked fine so I kept the old risers and installed new manifold and riser gaskets. Running fine with no leaks and normal engine temp.

My question is how hot should the manifolds and risers feel? When we ran the boat Sunday my wife noticed a smell while I was skiing. Everything looks fine but the manifolds and risers seem pretty warm. What is normal....should they be warm to the touch, hot to the touch, or too hot to touch? There shouldn't be anything blocking normal water flow but I never paid much attention to their temp prior to the swap so I don't know what normal feels like.

Thanks for the helpShould be able to touch the exhaust risers with a decently quick feel. One bank will typically be hotter than the other but neither should be too hot to touch.

This has been discussed many times here and you should be able to find a lot of info. Click on the link in my sig line or do a search.

That's all I know...

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03geetee
07-03-2012, 03:35 PM
Assuming all was installed correctly there is a specific way the riser gaskets have to go in relation to a hole lining up. I will do a quick search to see if I can find it, but it sounds like you have it together right if shes running good.

JTR

ProStar Slalom
07-03-2012, 04:14 PM
Assuming all was installed correctly there is a specific way the riser gaskets have to go in relation to a hole lining up. I will do a quick search to see if I can find it, but it sounds like you have it together right if shes running good.

JTR

The gaskets are in correctly with the blocked end toward the stern. I can place my hand on the risers but can't leave it there for too long....just want to make sure that's a "normal" riser temp.

BrianM
07-03-2012, 04:39 PM
The gaskets are in correctly with the blocked end toward the stern. I can place my hand on the risers but can't leave it there for too long....just want to make sure that's a "normal" riser temp.

That is normal.

ProStar Slalom
07-03-2012, 07:11 PM
Thanks for the peace of mind, guys.

mikeg205
07-04-2012, 06:06 PM
all good...post some pics...and go ski!

imracin68j
07-09-2012, 09:35 PM
My exhaust didn't have any gaskets, just some silicon.