Mikentucky
Member
- Jul 31, 2020
- 61
- Boat Info
- 1994 400 Express Cruiser, "Lollygagging"
- Engines
- twin inboard Mercruiser 7.4L Bluewater, straight drives
Yup....that is the one Mercruiser recommends. My problem is that on four sizeable spots there is 15-20 lbs of antifreeze pressure. After pulling apart dozens of these things....the Mercruiser block off gaskets distort and in some cases weep antifreeze into the raw water jacket. When a customer says I'm losing antifreeze and it isn't in the motor.....it is one of the likely culprits which is why I use something else.
So quick request for confirmation from you seasoned marine mechanics that I'm not doing something I shouldn't....
My boat is 100% freshwater since new. It has the OEM stainless elbows which theoretically shouldn't deteriorate in freshwater. Inspection looks like no sign of internal or external degradation, rust or otherwise. Manifolds also show no internal degradation and minimal external rust, but I know they're cast iron and contain coolant mixed with water, so internally I question their robustness WAY more than the stainless elbows--I plan on replacing them on both engines.
My question is, could I feel confident re-using my 100% freshwater stainless elbows and replace just the gaskets/manifolds? Or should I definitely replace the elbows too, just to be safe? I plan on installing the full restriction Quicksilver gaskets that Air O'Nautical showed above and below a stainless blanking plate that Play Date showed. I don't like being a "parts changer", I'd rather troubleshoot, find the problem, and repair as needed...but I sure don't want to be doing the risers in a few years because I missed something internally on the stainless risers.