[rther]

I'm having a lot of trouble figuring this one out. It's a two cylinder propane engine.

The machine came in because the #1 cylinder's spark plug wire was ripped out, so the ignition coil was replaced. After starting it up and richening the fuel mixture at the regulator (it was set too lean to start), I heard it running on only one cylinder.

The #2 cylinder valve cover and exhaust manifold was cool to the touch after several minutes of running. I popped the valve cover and checked valve clearance, which was within tolerance (.009" for intake and exhaust). I changed the spark plug. I installed a new coil. Coil gap is .015".

The engine will run when only #1 spark plug wire is attached, but will sputter, backfire, and quickly die when only #2 spark plug is hooked up. Pressure in #2 cylinder is at 140 PSI.

I believe this machine had a new #2 cylinder head installed a few months ago.

This one has me stumped. It's getting fuel, it's getting air, it's being compressed, there's spark. I'm not really sure where to go from here. The only thing I can think of is maybe the gasket around the intake manifold was damaged when the head was installed and it's sucking air, throwing off the mixture.

I'd appreciate any input you guys can throw my way.

EDIT: Forgot to mention the plugs are gapped at 0.032"

 

[dehrhardt]

While I am not familiar with the propane set-up, a couple of things to consider.
First, do both cylinders share the fuel air mix, or is there a separate barrel for each cylinder? Also check for restrictions in the exhaust of whichever cylinder isn't running, (exhaust valve not opening or an obstructed muffler pipe)

As you said, if there is an air leak at the manifold for the affected cylinder, that will lean out the mixture.

Spark should be good if you used a gap spark tester to check it.

 

[rther]

There's just one carb and it feeds a shared intake manifold. The exhaust valve is free and is set to where it belongs. Not sure if there's any restriction in the exhaust and I'm away from the shop until Monday so I can only speculate right now.

If there was any obstruction, would that cause higher than expected cylinder pressure?

 

[30yearTech]

Make sure the coil is not installed upside down on the side that's having issues. Also make sure there are pinched or shorts on the kill wire lead to the coil in question.

 

[rther]

The coil's right-side up. I hadn't though of the kill wire. I'll try running it with that lead disconnected.

 

[30yearTech]

Make sure the valves are operating properly. Could just be a faulty coil on that cylinder. Kawasaki recommends replacing both coils when one side fails.

 

[rther]

Fixed. The valves were set properly and both coils were replaced. I swapped out the new spark plugs with some other new plugs and it worked. I have encountered defective new spark plugs rarely in the past too, so this is something to watch out for. It's difficult to repair something if the new parts you're installing are broken!

 

[dehrhardt]

Glad to hear you got it going again

 

[rther]

Thanks for the ideas guys.