2005 mercury optimax 115 compressor dead end diagnostics

[WhiskeyDown]

Hello all! I've been coming here for info for months and have hit a dead end on diagnostics. I purchased a 2005 18 foot pioneer with 2005 saltwater mercury optimax 115 from a neighbor a couple months ago. I was a small craft mechanic in the USMC so I had been looking for a older boat that needed some engine work. Turned out it was just the pisser hose loose and was flowing up the shields. Sellers friend diagnosed "engine blown"! I did some PM on it and got it running great until my starter died on me. When I put new starter on I took out compressor air filter to change, put new starter on cranked up and it ran good for a few minutes I remembered no filter and turned off. DOH Put new filter in cranked up and it ran for about 5 minutes and died. When I tried restarting it would run for about 2 seconds and die repeatedly. Info here led me to look into compressor/belt. Looked at belt and saw extra belt dust. Went to autozone and got a new belt and installed, still won't stay on. I got out service manual and checked pressure on air shraeder valve and only was getting around 40 psi while trying to crank(should be around 94psi. At this point the boat wouldn't stay on for 2 seconds, it would occasionally try to start for a couple seconds though. After seeing low psi my next step was check the air regulator by clamping on outlet hose for a second and look for spike, no spike which led me to believe it was the compressor. I bought a used compressor on ebay and just took off my "bad" one. I took apart bad one and could not see any metal, the Reed flaps appear to be fine as well. So now I'm afraid I've mis diagnosed and it may not actually be my compressor. I have a 1000 MCA battery with good voltage, good connections. Good stabilized ethonal free gas, new external separator. New filter in vapor chamber assembly. No key alarms Sorry for such a long post and thanks in advance if you made it through this! I am dumbfounded on how I could be getting low air pressure when this removed and opened compressor piston/wall/reeds look fine.

Engine Serial ot997787



John in Pensacola area