Compression Test - JD- A

[Anonymous-0]

Anyone know what the compression test is for an unstyled A John Deere tractor? The pistons are .045 oversized.
Thanks,
David

 

[Mike M]

Around 75lbs if still all fuel

 

[Anonymous-0]

Hey Mike - Thanks alot.
Also, Is the correct way to take the compression check on each side done just by turning the flywheel by hand? That's what I did.
David

 

[souNdguy]

5 puffs minimum, though many keep puffing till gauge stops climbing.

Do a wet/dry and compair results.

If the wet trst comes up from the dry test dramatically, then it is usually rings.

If wet and dry are low.. it is usually valves.. ( and rings.. or just valves alone.. )etc

Soundguy

 

[Anonymous-0]

Make sure throttle is open.

 

[Mike M]

Well that's about all you can do on that one ? Unless you hook up a flat belt to another tractor then it gets pretty dangerous on the RH side.
I can't say as I have really tested any that weren't electric start. The hand start ones I just turn them over and if there is any much at all they will usually run.

What kinda pressure did you get on your test ?
That 75 lbs. I think is listed at cranking speed for all fuel electric start ones so you may not be able to get that by hand ?

 

[Wayne from MN]

Get a cylinder leak down tester; they are much more reliable (safer because engine is stopped) and will pin-point how much & where the engine looses compression.

 

[Anonymous-0]

Well, I got around 30# on each side. That was with hand cranking the flywheel and also cranking the tractor on one cylinder while the other one had the compression tester plugged in. I still got about the same results???
One strange thing, I noticed is the left side runs better than the right side on just one cylinder running. The right side doesn't make much difference running when you pull the plug wire???