Have a pair of 540's getting water in both motors. We thought we had it fixed because we were getting it when it was run on the hose. The hose ended up having 145psi on it. We rebuilt both motors and ran with the drives on set up normal they ran great no water. We then changed the upper drives to 1.5 ratios from 1.36 boat ran great rpms went 5800 now water in the oil again both motors. These motors are N?A with 8.5cr gen VI's they have new intakes, Stainless marine exhaust cast iron heads and crossovers. Everything has checked out ok, they even have all new oil coolers. The motors before the gear change ran about 5000rpm's. All we did was switch ratios and now the water/oil mix is back any ideas?

did the idle rpm drop down at all at idlle it the extra load of the 1:36 gears?

what is your idle rpm in gear in the water?

Reversion maybe,,,,, how big is the cam, and whats your lobe seperation?

It idles around 900rpm, I don't know about the cam I know it is in the low .600's

.632lift 256 duration 114 center line it is a crane hyd roller. It run fine with the 1.36 drive ratios the ennine rpm increased 800rpm with the 1.5 could it be water psi?

Ok we removed the riser off and there is water in laying in down inside. So what does that mean

That would be reversion most likely. Cam overlap is causing water to get sucked back in. The only other cause would be cracked exhaust.

That is what we are kind of thinking, it doesn't have a lot of oil but it has it. We pulled the plugs out and they were dry, the head gaskets look ok as well as the intakes, alos the motors have a little trouble idling

Brian, good chatting with you yesterday.. I think that you likely have reversion, the water psi at speed may also be an issue, too high of PSI can also cause problems. There are psi valves that could be installed if psi is an issue.. I look Fwd to meeting you.. Jamie