Faulty compression tester and testing a 60 for compressi

Yesterday I was trying to test the compression on a 60 and the compression on both cylinders was only about 60. I put just the gage on the air compressor and it was right on. I put about a half pint of type F transmission fluid in each cylinder and is was about 90 then with same gage. Today I put the tester with hose in air compressor with valve core in and it was reading low but read accurate with core removed but it bounces so fast without it and bounced up to 90 in tractor. I went to carquest to get a check valve and the guy gave me a $15 coupler that I doubted would stop air one way when plugged in but he insisted it would work. Like usual he was wrong so luckily I bought a new $30 compression tester also and it has the same valve core concept on the end and it was accurate with air compressor and about 100 on each cylinder without putting oil in cylinders so I think that is pretty good? I was about to tear it apart today because of low compression and it has a little more blowby than I care to see but now I think I'll leave it. I took 2 videos of the breather tube, a couple days ago it seemed like quite a bit, but today doesn't look too bad but I took I blocked off crankcase ventilater intake and maybe the atf I put in yesterday is helping. Also I'm confused why my old China tester with core in end is reading low but not without and the new one with same concept is accurate. The tractor is gasoline only with 6.1:1 ratio and if you multiply 6.1 x 14.7 it is about 90 so that's what I thought it should be? I am about 700 ft above sea level.

https://youtu.be/y1TJK3IT6aM

https://youtube.com/shorts/eDhw8hKAxEs?feature=share

Have you tried replacing the ''valve core'' in the tester that's not working properly?

They are ''special'' (I think internal spring is weaker than a common tire valve core) and a compression tester typically will NOT work correctly with a standard valve core installed.

https://www.miltonindustries.com/deluxe-compression-tester-replacement-valve-core

ONE source for the correct core.

Thanks I'll try that. It's possible I
might of put one in from a tire in years
ago

Between the test with the old gauges that you added the oil to the cylinders and the test with the new gauges did you run the tractor? If not you still do not have a valid dry cylinder test numbers. Although, at 100 psi with somewhat oiled down cylinders I would probably not be getting ready to tear down the engine.

That is correct! LOL

I just had trouble with my old Hastings guage the other day & tried to use a standard valve core with no luck. The spring is considerably weaker in the core for the compression tester inlet valve. However a standard valve core can be used for the bleed off valve without issue.

They are ''special'' (I think internal spring is weaker than a common tire valve core) and a compression tester typically will NOT work correctly with a standard valve core installed.

Click to expand...

Yes I did run it for 15 min before testing with good tester so I think it's pretty good. Then I moved snow with it for a couple hours with crankcase ventilator working and the blowby wasn't too bad either. I think some of the smoke was from condensation.

How does it run?