SBC running thur hull 4" exhaust and Alpha drive. I was wondering why the water exiting the exhaust is MUCH warmer on the starbord exhaust than on the port side. The boat has always done this with the old motor and the new "Problem Child".....

BH

Mine does the same exact thing. One side (port) is warm, the other (Starbord) is so hot you can barely touch it.

The engines are running about 165 dg.

Forgot to add....my temps are about 150-160*

BH

Mine too, all of them, ever. I think its normal at idle. I assume they equalize at speed as the pressure and flow increases.

You need to make sure the plumbing runs are identical (side to side) going to the exhaust manifolds. If one side has longer runs, higher runs, more turns ect, it will get less flow. The sides need to be balanced. The other consideration is the state of the inside of the manifolds. Too much corrosion is one will cause the other the win the flow battle.


BT

Lenghths are identical. Note quite sure about what you mean by balanced. Did it with the old stock manifolds and the new Stainless Marine ones....

BH

I have an '86 Scarab 21' with the 5.7/Alpha set up. Mine does exactly the same thing, hotter on the starboard side. I am also running in the 160-165 degree range. It steams occasually after slowing down from a beating.

Seems like alot of people having the same symptoms but nobody has an explanation

BH

Balanced means equal number of 90s, similar elevations of hoses and a level tee in the front of the engine. If you are sure the manifolds are ok and your plumbing is balanced, you could try restricting the port side water flow to direct more flow to the sb side. This could be done by pinshing off slightly the hose going to the port manifold with a wire tie, just to see if you get a change.

Another area to consider is the "balls" in the thermostat housing. I've never had these on my boats, but they are common and if sticking can cause similar problems. Maybe a search on thermostat housings would turn up something additional.

BT