Compression low on cylineder one

I preformed a compression test on the cylinders today. All the cylinders showed up at 140 psi but cylinder 1. It had a dry compression of 100 psi and a high wet compression.

Is 140 bad for the rest of the cylinders, and as for one, what could be causing the problem. I'm thinking head gasket, what do you all think? The engine is all caked up. I'm fixing stuff one at a time.

I didnt think to look for water when changing the oil, but I dont think i saw any. Any suggestions? Oh yeah, I dont have access to a leak down.

 

For my 2 cents, if by wet compression you mean with oil squirted into the plug hole, then I would say you have a ring issue. If it didn't go up after adding some oil, it would indicate head gasket or leaky valve.
Maybe others will chime in with some other explanations. I've always used the above info to help isolate the problems.

 

weld a quick connect to an old spark plug and put cylinder to top with both valves close. pump air into cylinder and listen to crankcase if hear air . it bad rings..listen carburetor if you hear air it a bad intake valve ....exhrust ....bad valve ....bubble in the water .....head gasket

 

not too much air pressure though dont want to cause a problem...

 

140 is fine. You'd expect a little higher from a new engine, but 140 is not bad.

Evenness is more important than the average pressure, as long as the average is not really low. One cylinder at 100 and the rest at 140 isn't good.

Rick describes the wet test correctly. If you have one low cylinder dry, you did that test, and the pressure went up with the oil in the cylinder, that's a little surprising. Usually the rings wear out more-or-less evenly as the engine gets tired. Did the other cylinders go up with oil, ie did you get 150 on the 140 cylinders with oil in there?

The leak-down test (putting compressed air into the cylinder) is a good test, but I don't think it'll tell you a lot more than the dry-wet compression test in this case... assuming you did the test Rick describes and you get the results I think you did.