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Will anyone give advice on how to do a compression check on a motor that you are wishing to purchase? I bought a nice, used compression guage, but have never used one. It came with no instructions.
How many times should I crank the motor?
Just a couple of taps?
Does the correct lbs. have to be applied? or can I just thread it snuggly? (sounds bad:eek:)
Any and all advice would be appreciated.
Thanks!
oz
just thread the gauge in finger tight.... most gauges have a rubber o-ring seal. either pull the kill switch or pull all the plugs out so the motor wont start. do one cylinder at a time and write down compression on each cylinder. turn the motor over several seconds. i normally get someone else to turn the key over and i watch the gauge. if will quit increasing pressure on the gauge when the cylinder max's out. i like to actually run the motor till it gets to operating temp before i do a compression check. that is the way i do it. i hope this helps
Most definetly run the motor and warm it up some first. Then pull one plug at a time and check the compression. The gauge should have a release for the pressure afterwards, so if alone you can do it by yourself. Just like bigfish said. I also like to pull the bottom screw out of the lower unit and see if any water comes out. If so it could freeze or have froze and pushed the shaft out some. I have had several do this and have problems later on our of it. Check it out good. Hope this helped some
They should all be within 10lbs of each other.
Thank you for the instruction. This information is very, very helpful in getting me to where I can have some knowledge in purchasing a good motor instead of a problem waiting to happen. Thanks again!
You also need to check out how long the shaft is on the spark plug,if your CG has a long shaft on it and the motor use's short shaft plug's you will scar the piston.My CG kit come's with different adapter's to match that up.
Is it a 2stroke or 4stroke,some you check with trottle open other's not.