Oh gotcha. I'll check it this weekend. We usually trim it just up until the boat is running the most mph with no tabs and then bring it back down a touch. I'm not trimming it way up at all. Usually about +2 on the gauge. Usually cruise at 45-50 mph. I'm not currently running a sea strainer but definitely installing one before this season. If running a transom pickup into the second input for the strainer won't mess with anything I think I will do it for insurance. I make a lot of 30 plus mile runs at a time fishing offshore. I don't want to constantly be worrying about water getting to the headers. I don't have any issues at all with motor temps but keep discoloring the headers.

My engine guy told me on my old setup that I was blowing water out of the top of the side vents and I should plug the top 2-3 holes. It was fine at cruise. I never ran hard for very long so I let it be but if you are then it's a cheap fix to try

Anyone got a picture that shows how you plug the top few holes on the side inlets? I checked everything yesterday and there's no corrosion at all so I'm back to trying to eliminate it from sucking air from the side inlets.

Do you mean you pulled the water fitting as shown in the photo? That can be a real pita to get off. No other way to check it.

There is a service bulletin re the holes. I'll see if I can find it.

It just involves a tap and some pipe plugs.

I cheated. It's really hard to get to with the headers on so I disconnected the hose at the valve and ran a camera down it. There's no blockages or corrosion to be seen at all.