New Holland GT20 with a Kawasaki FD620D

[fxrs55]

Hello,
A co-worker has a New Holland GT20 that is a 2005 model.
He bought it new in 2008, it was a left over from 2005.
It has low hours and has been well maintained.
Out of the blue it now has no compression in one cylinder.
If you remove the spark plug and crank it over
it seems to have conpression on the first stroke but
none after that. But while cranking it over after the first
stroke it will try to suck your thumb in the spark plug hole.
If you stop and leave it sit for a little and try again it will
have compression on the first stroke and then none.
I can't find any where that it has Automatic compression
release. Anyone have any thoughs?
Thanks for any help. By the way this is the guy that
gave me a bolens/iseki G154/TX1300F that I have been
working on. I have posted in the iseki forum about
that tractor.

 

[fxrs55]

update, found the problem and tractor is fixed.

 

[jimmysisson]

Yeah, but what was it? You had an odd problem we'd like to hear more about.
Jim

 

[fxrs55]

Ok, I asked my friend to check everything again and note exactly
what was happening and when. With plugs removed he did a compression check on both cylinders. One cylinder had good compression and the other would have compression on first stroke and none
on any other continuous stroke of that cylinder. If you leave
tractor set for a few minutes it will then have compression on
first stroke but none there after. Also while cranking
engine over if you place your thumb over or in the spark
plug hole for the bad cylinder it will try to suck your thumb
in on the down stroke. He relayed this info to the next day
after going through the test the night before.
I told him he has some sort of problem with the intake valve in that cylinder.
If it has compression on first stroke and then tries to pull thumb in
on the more than likely the intake stroke then the valves are seating
and the rings are more or less good. If that is in fact the case then
intake valve is not opening. That night he removed the valve cover on
the bad cylinder and found the push rod was out of the rocker arm.
He reinstalled push rod and half fast adjusted that valve and tried to
start tractor and it ran fine for a minute and then cylinder went dead again.
He removed valve cover again and again the push rod was out.
He repeated the replacement of push rod and installed valve cover.
He started tractor and this time it ran fine. He told me these
findings the next day and He also told me that the anti backfire valve
didn't work and he though this problem started after it backfired
a few day back when he parked for the night. I wondered if
this could have held the intake valve closed on the intake stroke
and maybe bent or at least bowed it enough to pop the push
rod out of the rocker arm. Couldn't figure why it popped out
on him the night he found the problem the second time
because it didn't backfire. He then called a parts place
to inquire about a new push rod and during his conversation
with the fellow at parts place the parts guy informed my friend
that this is somewhat of a common problem with this engine.
It is caused by sticky valves hanging open and push rod
falls out of the rocker arm. The sticky valves are caused
by high alcohol level in the gasoline. My friend was advised
to remove both valve covers, gently pry up valve seal by
reaching through valve spring and pure some injector on valve
stem so it runs down stem and softens gummy deposit between
valve stem and valve guide. My friend has done this and tractor
has never run better.