18HP Kohler, Model CV-493S, runs then dies

[gmcpcs]

Greetings,
I have this engine on a Simplicity ZTR, which I got used, and it's pretty old. It runs fine, for about a minute or two, then it sputters and dies. It will do this even with the mower engaged, and mowing, full power, then it sputters and dies. I have replaced the fuel lines and filter, the fuel pump and the carburetor. I discovered that the spark plug was not fully tightened, so I removed that and checked it, it was fine but a little black. I put it back and secured it down, and still the same issue. Any ideas? My next options are to check the throttle and choke lines, to be sure they are moving correctly. This was a problem with the engine before I did the part replacements, so I think I am missing something else besides fuel.
Thank uyou,
GMCPCS

 

[bertsmobile1]

Hard to diagnose with the limited information you have given.
Starting point would be a proper cleaning of the carburettor & check of the float valve
Also try mowing with the fuel cap loose

 

[VegetiveSteam]

After it dies will it start right back up?

 

[slomo]

Air, fuel, spark and compression. Sounds like you have at least 2 of those. Verify good flow AT the carb. Strong blue spark when it dies. Need to load test the ignition coil/s.

 

[gmcpcs]

I went back out and fiddled with it again, and discovered that the new fuel pump was pumping backwards. I really don't know how that was happening, I just manually flipped the metal lever while it was off and stuck the fuel line on the other side, and it started coming through. I put the old fuel pump back on and it is running fine now, just some blue smoke at start up. Now I have the drive belt throwing, so that is a separate issue. Thanks for the throuble shooting ideas,
"Have you ever pulled the metal engine shroud and cleaned the top of the block and cooling fins? This is a yearly maintenance item in ALL engine manuals. Neglect this and you are looking at engine damage."
Good suggestion, slomo, that was another area that I saw some built up crap and blew it out.

 

[VegetiveSteam]

Yeah they're not all the same. On the Kohler OEM pumps there is an arrow showing the direction of the fuel flow. Not all aftermarket ones have the arrow. One flows right to left and the other flows left to right. I don't remember exactly why they had the different directions but I think it had something to do with how the engine was mounted in the equipment and where the fuel tank was in relation to the engine.

 

[slomo]

Clean the block and cooling fins down to bare metal. Just as the engine was bought new. Any oil, dirt, grass and bugs will insulate that spot on the engine attenuating proper cooling.