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Compresstion check

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nightstalker133

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"Hi, I have a 1989 Force 125HP

"Hi, I have a 1989 Force 125HP. motor 4 cylinder 2 cycle. I need to do a compression test. Do I check it by turning the motor over without starting it? Also, I am trying to order a overhaul gasket set, mainly for the head gasket. It has water coming out the top. But all I can find is up to 1988, on a 125HP. My motel #1251X9B ,serial#2163. Is this the Bmodel they are talking about, and will the 1988 gasket set work?part#P2875. Thank You,Steve"
 
"yep, B model, look at outboar

"yep, B model, look at outboardparts.com or maxrules.com they have the same kit # 2875


Comp check: Best results when engine is warm, but not necesarry.

pull all the plugs and <u> be sure to ground all of the plug wires to the block </u> you need to disengage the neutral safety switch, (small microswitch under the throttle connection on the motor, just tape it closed) Go WOT (wide open throttle) and check comp on each cylinder, crank a few seconds for each cyl. Not grounding the plugs can burn out your ign packs. Cylinders are independant of one another so the plugs being out won't give you a false reading. You should also do this in water, you don't want to spin the impeller dry for too long, or that will be your next project


If you are absolutely sure that your safety lanyard works, that will disable your spark also, but grounding the plug wires to the block is a better idea, just to be safe

If you think you are getting low readings, you can squirt a bit of 2 cycle oil into the cylinders, this will seal the rings a bit better, mimicking what your motor would be like actually running.

readings between cyl should be close to each other, but don't have to be exact. maybe +/- 10 %"
 
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