Hi there,

oh and they should all be even within 10-15 psi.
90 to 150 would be the expected ball park

Disconnect the ignition system before cranking

if you have all the plugs out, and crank the engine, wouldn't the spark have nowhere to go? maybe fry the computer and/or coil pack?  I don't know for sure thats why its a question.

You could put all the leads into a bucket to catch the sparks? A plastic one, obviously. Then you could tip a couple out whenever you wanted to light fires.

Cheers for advise did the test today 130 PSI across all 3 cylinders on my 2 stroke so all good.

Yes it does Chris, you should always operate the kill switch if you're cranking it over with the leads off for several reasons: a handy little fire is one of those reasons, a nasty shock is another. I know in the early days CDI ignitions didn't like an open circuit but not sure about modern systems - I'd play it safe, then there's the possibility of a big voltage hitting other electronic devices or even passing through the low voltage wiring. The insulation on the 12v stuff want stop kilovolts.

The best answer though comes from Mullins

I'm sure they would.

Question...If some one turned on the kill switch first on a 2 poke, then took off number 1 S/P lead and held it with a rubber glove and with the free hand inserted the compression tester into the number 1 cyl and cranked it 2 seconds to get compression would that do any damage even if it is not a efi engine.

Mullins wrote: You could put all the leads into a bucket to catch the sparks? A plastic one, obviously. Then you could tip a couple out whenever you wanted to light fires.