Honestly I have thought about doing that. Unfortuntely I would have to buy all the everything to switch it back. the boat came this way.

I'm hopin with the by pass, it will slow it down, and let the water stay in the block a little longer to heat up? I guess if nothing else, the water shoud be warming up pretty soon too.. 100 degrees (dam near) all this week!

luckily my boat is in the A/C so its not to bad workin on it!

4 3/16 holes seems a bit much to me if your not making temperature in cold water. I had a Hardin Marine 160 thermostat (i think, I know it wasnt 180) with just 2 3/16 holes in it. Even early in the year here with mid 60 degree water i could build water temp in the 160 170 range cruising and 180 wot. So i know the engine was getting warm. I didnt have an oil thermostat so I always took it easy until the engine was good and warm. I dint have an oil temp gauge either but i never had any condesation in oil. Just very little on inside of breather.

After a run Do you see steam coming from breather.

What does this indicate?

We are always on rathbun hope to see you out there some time!

I think it is just some light condensation. At least you are making progress with curing it.

I would play with some T-stats to try and eliminate it completely now. Reduce the number of holes or start with no holes and a 165* T Stat. Then go from there.

Griff, If I remove the holes in the thermostat will the exhaust still get water, before the thermostat opens?

Am I correct that the holes are to help reduce PSI?, if so since I installed the bypass, I would think I would be ok?

You have a bypass style crossover, so the exhaust will still get water. The holes are more to keep the temps and pressure more consistent. With the 4 holes and your water temp compared to the temp of the Tstat, I doubt the Tstat was even opening. It was more acting like a restrictor plate and flowing all the water through the holes.
With the Merc pressure valve, you shouldn't need to worry about the PSI now and can concentrate on getting a consistent water temp in the 140-160 range no matter what the rpms are.

try adding a PCV to the system, changed everything I own to run them, helps clean out the engine and keeps engine cleaner to boot...may help with this...

We will be down 6/16 Thurs-Sun next week. Staying at the marina hotel. We have about 6 boats in our group, and enought peeps to take over the entire hotel!

Get those head gaskets changed and get out there.

let me know if you make it out. would like to see the boat.

-Shane

ok follow up to this as I finally got to run the boat for 3 full days after the water psi bypass install.

Set the bypass valve at 15#. at 2500 its spitting some water, At 3000 rpms its dumping water pretty good.

Water psi gauge never went over 15# all weekend.

Water temp 130-150 all weekend. Oil Temp goes up to 230 at 3500 rpms after a few min. Never seemed to go over that, but I didn't push it WOT for more then a couple short bursts. Slow down, and it drops down to around 180-200.

First run I took the tubes outta the valve covers, and it blew chit over the top, white sludge. cleaned it up. Put the tubes back in (my tubes run to puke tank, not the carb) Run it again the next day, and nothing. NADA, Zilch. Checked oil, and it looked good.

3rd day, was the same as the 2nd. Checked oil when I got home, and still looked good.

Gonna keep an eye on it, but keeping my fingers crossed I am ok now.