compression checking -how?

[wajajaja]

hello, <br /> reading many topics on many things generaly always mentions compression readings. <br /> How is this done, suggestion on the gauge. <br />all help is apprieciated, i do have the seloc book. havent opened it yet. <br /><br />time to go home. thanks. <br />walter.

 

[rickdb1boat]

Re: compression checking -how?

wajajaja <br /><br />Head to your local auto parts store and buy a compression gauge for about $30.00 or so. Try to get the one that has screw-in fittings for the spark plug holes. They usually have 2 size adapters included, to fit most motors. Take it home and remove your spark plug. Screw the proper fitting into the spark plug hole and crank the engine over 4 or 5 times and read the compression. Make note of what the reading is on that cylinder. Then go on to the other cylinder(s) and compare the readings. You are looking for at least 100 PSI on the readings and each cylinder within 10% of each other. Let us know what you get....

 

[eurolarva]

Re: compression checking -how?

I believe you have to remove all spark plugs when testing the compression. Not just the plug from the cylinder you are checking.

 

[outboardguy]

Re: compression checking -how?

And it usually helps to have the engine at wide open throttle when cranking

 

[wilkin250r]

Re: compression checking -how?

It sounds like common sense, but I'll say it anyway. Make sure your kill switch is activated so you don't get a spark. If you don't remove the spark plugs and you have a spark, your engine could start, which would be bad. <br /><br />If the spark plugs ARE removed, you don't want your ignition firing without the plugs properly grounded or you could blow your CDI.<br /><br />Pull your deadman switch (which kills the spark) or ground your spark plugs to the engine block.