I'll post pictures of the compression test if you guys would like. I have taken it to 2 local boat repairs shops trying to get the fuel delivery problem fixed. They both confirmed that my specific Mercury motor is designed to operate at 220 psi compression. Look it up if you would like or check out the links below.

What's funny is that some of you old timers know less about motors than you care to admit. Time to catch up with the times guys.


https://youtu.be/fjS3CiiXOww

http://www.louisianasportsman.com/details.php?id=4989

Waco, you chimed in on a thread in which the original post was asking about compression numbers on a 225 pro xs which is a 2 stroke motor. Totally different animal than your 4 stroke motor. It threw a wrench into everybody's thinking when you posted 4stroke compression numbers and talking about sticking valves when the thread is about a 2 stroke motor. So I wouldn't get on here and tell these old timers to catch up to the times when you clearly don't know the difference in a 2 stroke and 4 stroke.

On top off all that wkh2006 said a four stroke can have cranking compression and have very little running compression. Camshafts in four strokes have intake and exhaust overlap that lowers the running compression. We do not care about people trying to jump a thread, with un-relevant information. Good Luck with your supply fuel pump problem.

this showed all your infinite knowledge of Merc/Mariner outboards immediately..even AFTER he says its a Pro XS.. most of us "old guys" blew ya off when you posted this on a thread that had ABSOLUTLY NOTHING ta do with what was being asked.....jmo

I have been doing this for 40 years, yes I'm one of the old farts, but I have never seen compression in a two stroke motor over 175 psi. This was in the "old " crossflow designed motors!