Has anybody on here switched to center rise and had a problem with reversion? I took off my logs and put on imco thumper with the short risers and when I took them off today I found water in all my exhaust ports with rust. The boat had a pretty bad surge at idle bit drove fine, I figured it was a carb problem. I think it's a stock 330hp harman 454, this exhaust is going on my new engine with an isky 280 mega cam, kind of worried now!
As you may know some condensation can occur (especially in the upper reaches of the engine) from simply cold operating temps and the oil not getting hot enough to dissipate the moisture that can be present in the crankcase , condensation milkyness wont increase the oil level, intermix from an internal leak eg head gasket, ex manifold leak intake leak etc will likely increase the actual oil level Tom
Thanks Tom. The oil shows no signs of water intrusion, Same under the valve cover. It's only a small amount in the exhaust chamber. I'm wondering if this is at all possible from running the boat during the day then leaving it uncovered that night. We get TONS of dew here, the boat is soaking wet in the morning if I forget to cover it. The exhaust flappers are tight, but maybe a combination of a warm engine cooling down over night with lots of dew? Somebody on the facebook jet boat page brought up that he had the same problem and after welding 8"pipe onto the riser to extend the point of water entry the problem was solved.