good running kohler 301 (sumtimes)?

[sore-toe]

Hi been awhile, I got a problem with a A/C 712 H I picked up a while ago. The guy I bought it from said it would run awhile and quit well he was right so I put new fuel lines,new fuel pump,cleaned the tank, new points,new condenser(twice),and finally a new coil with build in resistor. Well the problem continues but it will stay running longer than when I first got It, at first It would only run maybe 10 min. under a load now about 20 min. under aload (mower deck running). The tractor runs smooth starts easy when cool, but when it shuts down the motor sounds as tho it will sling a rod starts blowing smoke out the valve inspection plate then just quits. O'ya almost forgot did complete valve job reground and seat. Any help would be appreciated,I need some suggestions,Iam thinking of scrapin the Kohler for a 12H.P. briggs which I have but would like to keep the A/C 712 original thanks in advance.

[BLT]

As silly as this might seem, loosen up your gas cap and see it that makes a difference. Remember that cap either has to be off (bad idea) or real loose fitting. If that helps, vent holes in cap are plugged. Happens from time to time. Then, check breather for smoke problem. If that has a reed, it maybe be going bye-bye.

[PeppyDan]

It sounds like it may be overheating. Does the engine start run worse before it dies or does it just stop running? Have you tried to pull the choke out if it does start running bad before it dies? A couple of other things to check would be if the screen inside the fuel tank is plugged, new oem fuel filter( I have read here that automotive filters should not be used) or a mouse nest under the fan shroud. Dan

[sore-toe]

Well PeppyDan I was thinking over heating also It doesnt just quit it starts running real rough and shakes if I pull the choke out it will continue to run but no power just spits and sputters. But if I shut It down for just a few seconds it starts back up and runs great for a few min. (Its A mystery To Me)?

[DMedal]

Dan/Sore-toe- You say when it goes bad it is some better when you choke it? That part wasn't completely clear to me. Also you say it gets better even if off for only a few seconds. (less than 10?) If so, that pretty much rules out overheating. Being off for a few seconds won't cool it off much I think. From your symptoms I'm thinking fuel starvation, like BLT said. Others will know more. Try what BLT suggests with the fuel cap, ok? You've done most of the other obvious things already. You don't mention fuel filter. That's new also? But I don't see that fuel problems account for the funny stopping where it blows smoke out the inspection plate. I'm very curious to see what this turns out to be. -Don

[PatRarick]

Sounds to me like the ignition timing is off. I've had a couple of 16 horse Kohlers with that problem. One on a welder and the other on a tractor. I'm not in the shop so I don't have the book with me to explain the exact procedure. I know there's a plug on the carb side of the blower housing where you can find a timing mark on the flywheel. The point setting controls the timing and .020" is only the initial point setting to get the motor to run. It's usually close enough that it doesn't need to be changed, but there are instances where it does. From what you are explaining, ignition is coming too early, meaning your points are set too close. I currently have an old Cub Cadet in the shop with a 12 horse Kohler that's a little worse off than yours. Owner "rebuilt" the engine, but he couldn't get it to run right after his rebuild. Only about 3200 rpm with the carb held wide open and it overheated when he tried to work it. I could hear that the timing was way off. After setting the timing, the points are set at .045", and the engine starts, runs, and performs beautifully at that setting. I need to tear it down this week to see what he's done wrong, so I don't know what the problem is as of yet.