Intermittent Kohler Problem

[captsomer]

OK. I put on the new coil pack (left cylinder) cleaned the cooling fins and everything, oil / filter change, new plugs, new fuel, new fuel filter, splashed a little carb cleaner in the tank just for kicks and I STILL HAVE THE PROBLEM!!! :confused2:

I checked spark in both cylinders, both good and strong.

While it was running poorly, I pulled the left plug wire. The RPM's dropped slightly and it got a tad bit rougher, maybe. Next, I pulled the right side plug wire. It started running like crap big time! It was back firing flames out the exhaust end everything. It scared the **** out of me. I thought I'd been shot!:laughing:

Guys, I'm running out of ideas. I'm thinking its a valve issue in the left cylinder, but the compression test still reads OK. Could it still be a valve issue? The carb is clean. Choking it doesn't affect the problem much, if at all. Neither does throttle. I really don't think its fuel related. The sparks are hot and there isn't much in the timing to adjust so I'm kind of ruling out ignition too.

I'm not afraid to pull the head and see, but I was just trying to wrap my brain around what this could be and hear from you guys first. I may have time for it this weekend.

Thanks

 

[Diamondpilot]

Long ago, and far away, my brother had a 383 Barracuda (yea, wouln't we like to have that today) It ran just fine until you pushed it a bit, and then it would break down. Chased it around the place, and finally found out it was the ignition wires leaking voltage when they got hot, or the engine was really cranking........ not that he ever did that.

I had the same thing with a boat and GM 383 Stoker. It would run all day long at 3,700 rpm but as soon as you stomped it down to 4,000 rpm or more it would miss out. Chased it for 3 months and tons of new parts including cap, rotor, plugs, wires, fuel tank vent hose, fuel pump, ect. Turned out to be a $55 ignition module breaking down with heat. It was a Mercuriser Bravo with the Thunderbolt Ignition.

Chris

 

[Treemonkey1000]

Did you swap spark plugs or replace them? Does the coil pack include a new plug wire? I am not sure if it would work to check for a head gasket leak but spraying WD-40 around the head to see if it either blows it away on the compression stroke. Or if it sucks it in then it makes it run worse. It does sound like you are using good troubleshooting techniques.. Another thing is squirt WD around the intake side for the carb. You might have a intake gasket leaking and leaning out the fuel mixture too much.

 

[Diamondpilot]

OK. I put on the new coil pack (left cylinder) cleaned the cooling fins and everything, oil / filter change, new plugs, new fuel, new fuel filter, splashed a little carb cleaner in the tank just for kicks and I STILL HAVE THE PROBLEM!!! :confused2:

I checked spark in both cylinders, both good and strong.

While it was running poorly, I pulled the left plug wire. The RPM's dropped slightly and it got a tad bit rougher, maybe. Next, I pulled the right side plug wire. It started running like crap big time! It was back firing flames out the exhaust end everything. It scared the **** out of me. I thought I'd been shot!:laughing:

Guys, I'm running out of ideas. I'm thinking its a valve issue in the left cylinder, but the compression test still reads OK. Could it still be a valve issue? The carb is clean. Choking it doesn't affect the problem much, if at all. Neither does throttle. I really don't think its fuel related. The sparks are hot and there isn't much in the timing to adjust so I'm kind of ruling out ignition too.

I'm not afraid to pull the head and see, but I was just trying to wrap my brain around what this could be and hear from you guys first. I may have time for it this weekend.

Thanks

I would put new plug wires on it. Sounds like a plug wire that has a crack and is going to ground. Had a Toyota truck with 168,000 miles on it when I traded it. That was the only thing I had to change on that truck along with a $25 slave cylinder on the manual tanny.

Chris

 

[captsomer]

Did you swap spark plugs or replace them? Does the coil pack include a new plug wire?

I changed out the plugs (both) all together with new ones. The coil packs have their own plug wire permanently mounted to them.

I don't know if this means anything but when I first started it up after all of this work, it was running rough and was belching LOTS of white smoke out the exhaust. I fogged my entire yard! It did this for a good two minutes. I shut it down and fired it up later in the day and it was not smoking anymore. It was just running bad. At the time I figured it was just the carb burping itself into action or something. The engine stood upright the entire time so I don't think it was oil leaking into the cylinders. Water from the pressure washer cleaning maybe? I wouldn't think water would last that long though.

 

[Jim Thompson]

Check for a worn lobe on your cam for the side that is missing. Common problem with Kohler command engs. Also, check for bent push rods or hyd lifter that will not compress. You check the cam by removing the valve cover and checking the movement of your rocker arms.

 

[captsomer]

Check for a worn lobe on your cam for the side that is missing. Common problem with Kohler command engs. Also, check for bent push rods or hyd lifter that will not compress. You check the cam by removing the valve cover and checking the movement of your rocker arms.

Thanks Jim.

Does anyone have a good place for cheap parts? Not much on EBay for me.

 

[2manyrocks]

I wouldn't call them cheap, but I ordered a coil from Tulsa Engine Warehouse on the net--something like $35 plus a $8.95 shipping charge and it cleared up my problem. I had some other parts to order so I didn't fret the shipping charge.

It is stuff like this that will drive a person crazy trying to fix it.

 

[Gizmo2]

captsomer,
Seems like the same problem I had on a 20hp Kohler engine. This may or may not help. Read the whole thread. I don't think it was really the carb but something to do with the spacer plate between the carb and engine. Can't remember.

http://www.lawnsite.com/showthread.php?t=30335

 

[captsomer]

Hey Guys, I'm back. It took me a while to get back to this project but I got it taken care of now.

I pulled the head on the #2 cylinder (the intermittent one) and everything looked great. I put it back together.

Next, I pulled that Spark Advance module box that mounts on the side of the engine. It seems that that was the problem. I didn't think that it could only fail on one cylinder. Thats why I didn't look into it earlier.

Any way, I put everything back together and she is purring like a kitten again. All that trouble from a little black box.


I should have known...

Thanks for all of the input on this guys.