cyl 1=106 <br />cyl 2=103<br />cyl 3=116<br />cyl 4=121<br />cyl 5=116<br />cyl 6=126<br />........1992 Mercury 200 hp. Motor has about 50 hours on it.
Re: Are these compression readings out of balance?
Hi Bush Cat<br /><br />As all are above 100, the motor will run fine on all cyls if ignition and carbs are OK.<br /><br />However a max difference of 15% between highest and lowest is usually the limit. Have you ever decarbed this motor ? Do you know the 50 Hrs is correct ?
Re: Are these compression readings out of balance?
Sorry Schematic, i typed when you posted. However 50 Hrs on a big expensive motor, in 10 years isnt much, sometimes a motor has ran more than you think, a decarb might be in time, my little motor i disassembled already had some carbon build around compression rings before 50 Hrs.
Re: Are these compression readings out of balance?
I have had nothing but problems with this motor. When I got it off the estate it had no.1 and no.2 pistons eat up. The Pistons were burned up so I replaced. Kitted the carbs and put back together. Ate up no.1 piston again after 12 hours. Went through carbs again and found that top carb had the air idle jet was in too much. This is where I am at now. Timing is perfect, carbs all rebuilt and jets set a factory specs, all I have to do is lake test it.
Re: Are these compression readings out of balance?
Check timming on each cylinder,and for double firing, you have to mark flywheel. Check the holes in the side of the main jet, if you over tighten the jet, these holes become egg shaped and smaller, ruins the jet. Check in with www.screamandfly.com search your engine and burnt piston.
