proper way to do a copression test

[zanman]

can any one tell me the correct way to do a compression test on a twostroke outboard motor,hot cold, squirt of oil or not.<br /><br />thanks Z

 

[Kenny Bush]

Re: proper way to do a copression test

Run motor until it reaches operating temperature. Then disconnect all sparkplug wires. Open throttle to wide open. Engage kill switch if you have one. Unscrew #1 plug. Insert compression guage. Turn motor over for about 3 seconds. Record results. Proceed to number 2 cylinder......3..4..until all cylinders are done. There should no variance of more than 15% from the lowest reading to the highest.

 

[wilde1j]

Re: proper way to do a copression test

Suggestion: remove ALL spark plugs before beginning!

 

[Moving Target]

Re: proper way to do a copression test

Ground out plug wires if you dont have a kill switch.

 

[Fouled Plug]

Re: proper way to do a copression test

If you get a low reading, a squirt of oil will indicate bad rings if it bumps up compression.

 

[zanman]

Re: proper way to do a copression test

thanks everyone Z

 

[Kenny Bush]

Re: proper way to do a copression test

Leave the plugs in....... only remove plug for compression guage. If you leave out all plugs, it will trick test(must have each chamber isolated).