issues with my kohler cv15

[38racing]

I've had it many years on a sears lt4000 ,using in winter with snowplow. I was getting it ready in November. It has the mechanical fuel pump that goes up over the engine. Normally after a long sit I need to spray carb cleaner in for a bit to get it running. That's what I did. I recall it was tempermental but it finally ran fine. I changed oil and filter and waited for snow. When that time came I could not get it started. Did usual checks, Had to use brake cleaner ( flammable version) to kick start. But it just seems to start and then backfire out the carb. I did spark test and got questionable results. 2 different spark plugs. Did the kill wire off thing . no change. Looked up coils testing and apparently kill tab to laminate should not be infinite but it was. Decided on getting a new coil. First test on new one have me an ohm reading on the test but after installing it symptoms are same except inline spark tester show a good spark. I pulled the valve cover. Valve action looks right with flywheel. Can't check clearance easy with the hydraulic lifters.
Did both compression and leakdown. Compress good. With flywheel near TDC and not holding it I got gauge up to 60 psi input , no hissing and about 6% leakage on the gauges.
While testing more of course a backfire had the excess brake cleaner flaming so I managed to melt the choke lever plastic so no hole for the choke rod.
I have the flywheel bolt removed but only see keyway of the flywheel , can't see the keyway of the crankshaft. Next step is pulling it but can't figure how it would shear after all these years of just running with a plow, no mower.

[bgsengine]

checked your exhaust outlet? Had one in that had a ground hornet's nest built up in the muffler, (amazingly enough.. I assume the freeze killed the bees, dunno..) It could suck, squeeze and bang but not blow..... but plugged with mud or anything else, could see same results...

[KE4AVB]

You won't see the crankshaft keyway as it uses a Woodruff key which is a semi half moon key.

[38racing]

Well not plugged exhaust. Previously it start and run slow with choke applied but when throttle moved from choke to run it just stopped. Not even doing that now. I decided to check fuel . I loosened bowl and gas ran out. Cranked a bit. Checked again, no fuel in bowl. It has mechanical fuel on side opposite carb. It's not pumping. I tried priming it but no success. I connected a gravity tank. Verified bowl filled. Still nothing at all holding choke closed. I'm getting shy about spraying but tried carb cleaner again. Just a couple bangs and nothing even with additional spray. I suspect the plug is getting wet so no additional fire. Supper time arrived. I'll retry with dry plug but I think it's pulling flywheel time.

[38racing]

well it's running great. Never did pull flywheel. At one point it would run if I kept choke closed so I serviced the carb. Got back to it not running at all. Really felt that it was a spark issue. I grounded plug out of engine with a booster cable to the battery ground. Inconsistent spark on the 3 plugs I had. I actually put old coil back on. same results. So obviously you are saying why didn't I try a new plug. At that point I didn't have one. I buy in bulk from rockauto so needed to make an order and was also undecided if I needed an o2 sensor for my car to go on same order. However I did find a ngk bkr5es at my local canadian tire for not the usual double price. Put in it, old coil still, and it runs better than ever. Mind you on gravity feed setup. Still went down another rabbit hole. Since I've had issue with the mechanical fuel pump I switched to a pulse one . At first it wouldn't pump. But I found even with line below tank it didn't flow. I could get a bit out by compressed air into fill tube but still no flow. I swear I thought I saw fuel in the tank at one point but looking closer I just saw plastic. So I added fuel and got the line flowing. Connected to pump and it flowed. Apparently my prep in november didn't include filling the tank. I plowed the driveway today without a hitch. I'm thinking now the sometimes missing last year was the plug on its way out.

[SUKI]

Yes you do kinda need fuel in the tank. Oh well it like try to start an engine but forgetting to make the kill switch is off. I feel like an idiot for doing that one. But I admit I prefer and am use to those momentary kill switches on handhelds.

But I had a customer just last to bring in a push mower that would not start that the only was wrong was no fuel.

At least you didn't what my brother's boss did to his mower. He was mowing, got a call which he answered, and when he went to finish the mower would not start. He got so mad he took a sledge to the new mower and beat the heck out of it. Then someone asked him, "Did you check the fuel tank?". When he did it was out of gas.

[38racing]

Well at least lack of fuel wasn't the reason it didn't run
Since it wouldn't run right on the gravity setup until I replaced the plug.

[KE4AVB]

Well at least lack of fuel wasn't the reason it didn't run
Since it wouldn't run right on the gravity setup until I replaced the plug.

This is why we suggest using a known good plug for testing. Even new plugs can be bad.

I have had plugs toe fire outside the compression zone and still not fire under compression. I even one weird plug that cause surging in a Briggs engine that appeared to be a bad governor setup. Since that engine was running I had assumed the plug to be good. After going through the engine 3X I decided to try a new plug as a last resort which fixed the surging.