Exhaust manifold temp, with fwc, full system

[stevea661]

These readings are taken with the boat running on the muffs at about 1200 rpm. The system is an omc 210 from san juan engineering and is a full system with coolant running through the manifolds. The engine has less than 1 hour on it from making adjustments, timing etc and getting baise line readings. Engine is a 350 chevy that is carberated and is OMC. The port side manifold runs about 30 degrees hotter than the starboard, the manifolds were not changed durring the rebuild. The port side manifold looked new, I thought if I was going to have a problem it would be on the starboard side. The port runs about 217 and the starboard runs about 185-190. I already have 2 new manifolds comming, if I do one I might as well do the other and start off with 2 new ones. does anyone have any Ideas what could cause this differance or has anyone else ever had this problem and how was it solved. Is it a problem? Am I on the right track? Thanks in advance

 

[Coastal Manifold]

Your on the right path.I would not run this boat untill the manifolds are replaced. Good Luck.

 

[stevea661]

Your on the right path.I would not run this boat untill the manifolds are replaced. Good Luck.

So what should normal operating be under the above conditions?

Just pulled the manifolds the port one (hot side) looks like its good, no scale at all. On the other hand the starboard one has some scale. Any Ideas?

 

[stevea661]

I just got the new manifolds installed and put it all back together. Same thing:smt021. Although I think the way the boat is sitting, high in the port stern section is causing air to become trapped in the exhaust manifold. The port feed hose is also longer by about 12". When I lift the hose, the temp on the manifold drops 10 degrees like now and the filler neck in the heat exchanger bubbles. I'm thinking, get the boat with the bow up, shorten the port feed hose, and see what happens:huh:. Any input would be appreciated. Thanks in advance. Oh and the boat is sitting on a trailor.

 

[unlvrebel]

I can't really add much valuable info here other than to say that I dropped an IR gun on my manifolds and risers the other day while flushing with the muffs and one side was about 15 degrees hotter than the other. I don't remember which one though. The temp escapes me, but wasn't too hot. Maybe 150 - 160 or so. Risers were within 5 degrees of each other at 90-95.

 

[stevea661]

I can't really add much valuable info here other than to say that I dropped an IR gun on my manifolds and risers the other day while flushing with the muffs and one side was about 15 degrees hotter than the other. I don't remember which one though. The temp escapes me, but wasn't too hot. Maybe 150 - 160 or so. Risers were within 5 degrees of each other at 90-95.

Do you have raw water or coolant running through your manifolds? The temp on the risers is about the same as mine, but the risers run raw water. My manifods run coolant.

 

[unlvrebel]

Raw water for the whole deal. Perhaps that's why mine run cooler.

 

[stevea661]

Raw water for the whole deal. Perhaps that's why mine run cooler.

I hooked up the trailor and turned the boat around, bow up instead of down. Both manifolds read about 200 now. I guess I needed to burp the system. I don't think I'll have a problem once I get it out and bouncing around. The risers which are raw water cooled are about 100. I guess I should have done this prior to changing out the manifolds. Thanks for the input.
Oh and readings are in Farenheit, not Centigrade. I think 200 c is like the surface of the sun or something :grin: