VK540 run on one cylinder only.

D

DeepSnow

New member
Joined
Jan 24, 2009
Messages
11
Age
45
Location
quebec
Hi guys,

I have a weird trouble with my VK540 2002:

At idle, it run only on the MAG cylinder, the sparkplug on the PTO side is always wet. As soon as I give it a little throttle both cylinder run fine and the motor run very well.

I've changed everything: sparkplugs, the whole generator assembly, the ignition coil, everything!!! I took all the parts on my father's good running VK, and this thing still running on 1 cylinder at idle.

Also, I switch the reed valves assembly from the PTO side to the MAG side, and the PTO cylinder still not running.

It look like it getting too much gaz at idle only in the PTO side.

The crank seals look fine.

Any idea?
 
sounds like a sticky ring to me. give it a shot of seafoam or ringfree. uncles buddy had this problem with his and it seemed to cure it.
 
well that is what his was doing except on his it was the mag side piston. kept fouling the plug in that hole. we dosed it with seafoam and fresh gas and he has not had the problem since. of course he is using it more now than before so that will help as well.

try a compression test and see what the # are.
 
i think its a burned colv, check the compression.. you should know when you try to start it, that its no compression on this Cylinder.
 
I've just checked the compression, 105 psi on both sides, what's are the normal psi for a VK 540?
 
i ahd one doing the same thing and it was the gasket blown out on the base of the cylinder.usually this would cause a lean burn down but on the vk it just caused it to idle on one cylinder ,above idle it was fine.
 
9801srx said:
i ahd one doing the same thing and it was the gasket blown out on the base of the cylinder.usually this would cause a lean burn down but on the vk it just caused it to idle on one cylinder ,above idle it was fine.
Click to expand...

When the gasket was blown, did you see some oil leak around the base of the cylinder?


The next step will be tearing-up the whole engine appart I guess.
 
i think there might have been some oil around the base gasket.but the sled was used for a long time with the problem.i found the gasket blown out after checking every thing else i could think of checking ,decided to pull the cyl for a look and noticed the gasket sticking out down between the two cyls at the base of the transfer port.
 
depends on his gauge. as long as both cylinders are the same or within 10lb on the gauge it is fine.

never heard of the gasket one mentioned above. could be that. try re-torquing the heads and jugs to see if that makes a difference.
 
I've got all the gaskets and seals, I will open the whole engine this weekend and check everything.
 
Hi,

Take a look at the PTO side piston:

ring1.jpg

ring2.jpg


The ring is bend!!!

How can this happen?

I've removed the cylinder very carrefully, I don't think the ring can hang somewhere.
 
SRX500_129 said:
they most been heated up because maybe the oilpump does not work? check it out.
Click to expand...


The oil pump work fine.

Also, the crank seal is worn out on the PTO side.
 
looks to me that the ringd must have been stuck in the ring grooves at some time and the blow by got the ring hot enuf to deform them.you can see that the ring was not even touching the cyl in the picture .the rings should be shiny all the way around if they were sealing properly,not shiny in some spots and black in others.if pistons are in spec make sure to clean out the ring groves before putting on new rings.also check to see if the cyl's are in spec (out of round and taper). oh ya how were the cyl gaskets?
 
9801srx said:
looks to me that the ringd must have been stuck in the ring grooves at some time and the blow by got the ring hot enuf to deform them.you can see that the ring was not even touching the cyl in the picture .the rings should be shiny all the way around if they were sealing properly,not shiny in some spots and black in others.if pistons are in spec make sure to clean out the ring groves before putting on new rings.also check to see if the cyl's are in spec (out of round and taper). oh ya how were the cyl gaskets?
Click to expand...


Cylinder gasket seem to be OK and the cylinder and piston are in great shape, I will install new ring only on both pistons.

Also, both crank seal were bad.
 
9801srx said:
looks to me that the ringd must have been stuck in the ring grooves at some time and the blow by got the ring hot enuf to deform them.you can see that the ring was not even touching the cyl in the picture .the rings should be shiny all the way around if they were sealing properly,not shiny in some spots and black in others.if pistons are in spec make sure to clean out the ring groves before putting on new rings.also check to see if the cyl's are in spec (out of round and taper). oh ya how were the cyl gaskets?
Click to expand...

if you look at det second picture you will see that the piston and rings have a burned place, and a place that is not burned. last time i fixed a problem like that, it was because of no oil ..
 
I've replaced both ring set , all the gasket and seals, now the engine run like a new one!



looks to me that the ringd must have been stuck in the ring grooves at some time and the blow by got the ring hot enuf to deform them.you can see that the ring was not even touching the cyl in the picture .the rings should be shiny all the way around if they were sealing properly,not shiny in some spots and black in others.if pistons are in spec make sure to clean out the ring groves before putting on new rings.also check to see if the cyl's are in spec (out of round and taper). oh ya how were the cyl gaskets
Click to expand...


The ring is shiny all around, the black spot you see in the picture are the result of bad lightning and shadow.
 
Was this motor apart before? The ring may have been bent during assembly. Age is your worst enemy when it comes to crank seals. Glad to hear you got it going again.
 
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