AmiableDave

Right. Just trying to understand the forming of condensation and how to tell with other exhaust.

Donzi1979

Ok so I switched the t stat housing out to the OE style but is an aftermarket, and water pressure is better, maybe a tad low but ok. My question to the OSO brain trust is which gasket to use on the upper housing cover the one on top of the t stat that has the hoses that feed the lower portion of the exhaust manifolds. I used the one in the kit that didn't have any restriction (thinking that would be better), but noticed the Merc gasket I ordered but wasn't here in time for the weekend has a small hole (the one on the right in the pic) that restricts flow until stat opens, which to me seems way too small. I realize the the "T" connector with the check balls will flow some water to the manifolds but the upper portion first not sure if this is an issue. Only reason I ask is when running on the hose at home it starts to get much hotter than normal and think it's possibly not sending enough water to the recirculation pump, but works fine in the lake. Also never had it really get too warm on the hose before, I know it's a small issue just looking for some insight.

BUP

follow the HP 500 T stat housing set up and how the actual T Stat is installed plus the gaskets used. Back in the day I would see this installed incorrectly and Merc recommends the correct type of T stat installed as well. The HP 500 service manual is good to have here inwhich I know you have it. Heck you bought it off of me 2 years ago or close to it.

Your first installed T stat housing uses different gaskets than what is used in your last install.

Donzi1979