GTX 2100 miss

Ian181 · #1 03-16-2025, 05:09 PM

OfI have a 2013 GTX 2100 and it suddenly seems to have developed a miss somehow. I've cleaned the carb, replaced the plugs, the fuel filter is practically new, air filter is good, coils are working good, and fuel pump is pumping, what am I missing? It starts and runs, power steering works, deck engages, but I can tell it has an intermittent miss.

CubDieselFan · #2 03-16-2025, 05:59 PM

How did you check the coils? Do you have a spark tester? Could be a stuck valve. You could take the valve cover off and check those pretty easy.

Billy-O · #3 03-17-2025, 10:29 AM

I'd look for sparks arcing off spark plug wire(s) as if insulate is wet or worn.

Ian181 · #4 03-17-2025, 06:41 PM

I really appreciate all responses.

Yes I have a spark tester, appeared to be firing good on both plugs. Would have to remove the engine to check the actual coil gaps.

Haven't checked the valves, never messed with them before.

Cub Cadet says the fuel pump for that model/engine should have 39lbs.
(+/- 3 lbs.) of pressure, that seems extremely high when a mechanical fuel pump is usually 5-7. I have a fuel pump pressure tester, but it's not rated for over 25lbs.

Air filter is good.

CubDieselFan · #5 03-17-2025, 10:46 PM

Quote:

Originally Posted by Ian181

Cub Cadet says the fuel pump for that model/engine should have 39lbs.
(+/- 3 lbs.) of pressure, that seems extremely high when a mechanical fuel pump is usually 5-7. I have a fuel pump pressure tester, but it's not rated for over 25lbs.

39 psi sounds like the spec for a EFI engine. Yours has a carb so that would be too high for your engine.

Ian181 · #6 03-18-2025, 11:12 PM

I noticed today that my fuel filter was really low when the motor was running? I checked the flow from the tank with the line disconnected and it seemed to flow good, although it did flow a little better with the gas cap removed, is that suppose to work that way?

I ended up pulling the motor because of a bad oil leak at the front cover where the PTO goes on. Some of the bolts on the cover were really loose. I had replaced the front crank seal and repaired an oil leak there two years ago and forgot to loctite the bolts during the assembly, @/#$@, that won't happen again! With that leaking that much is it possible there was a vacuum leak enough to cause the motor stutter?

I also found about two inches of insulation missing on the fuel shut-off valve wire at the rear of the motor/carb. I cleaned it off good and re-taped it with some electrical tape, I couldn't get shrink wrap over it because of the terminal ends. I did check the plunger when I had it off to remove/clean the carb and it worked smoothly.

I'm going to check the gap in the coils while I have everything off, but the plugs are firing good, and the battery's charging, so there shouldn't be anything wrong with the stator.

Oh yeah, when I picked the motor up to set it up on my workbench I snapped the top of the dipstick off, it never fails that I add to my workload somehow someway, freaking Murphy, why can't he ever take a day off!

ol'George · #7 03-19-2025, 09:36 AM

Its normal for see-thru fuel filters to not be full of fuel on gravity systems.

I wouldn't use loctite unless it is recommended in the repair manual, as you might be the next guy to try to get the small bolts removed.
Proper torque should be suffice or possibly a retorquing after some usage if a paper gasket is used.

Ian181 · #8 03-19-2025, 04:40 PM

I would only use a drop of medium strength 3/4 of the way back the bolts and torque them to the 15 in. lbs. specs.

On a side note, does anyone know where toI can find the entire torque specs for my Kohler Command engine?

Follow up: Talked with a friend who owns a lawn and garden repair business, he said it would be best to not use any loctite, just torque to specs, run the engine to operating temperature, then re-torque the bolts again after it cools.

Ian181 · #9 04-03-2025, 11:52 AM

Re-cleaned the carb, opened up the main jet and emulsifier tubes slightly with a torch cleaning bit (next size that wouldn't fit through), replaced the o-rings on the tubes and shut off solenoid plug leading to the main jet, reset the gap on both coils, and replaced the ground wire coming off the fuel shut off solenoid, the insulation was chewed off the original (vegetable oil based) one.

Per my lawn business friend suggestion I drained my fuel tank and mixed up a gallon of premium gas with (50:1) 2-cycle oil mixed in to run through initially, supposed to help clean any valves that might be sticking.

I got everything back together, installed the motor, warmed it up (no misfire), left it cool, and re-torque the front cover bolts.

I'll definitely be keeping an eye on ithe front cover, don't want a repeat of this again! Thanks for all your help and suggestions, as always they were very much appreciated!

ironman · #10 04-03-2025, 12:34 PM

Quote:

Originally Posted by Billy-O

I'd look for sparks arcing off spark plug wire(s) as if insulate is wet or worn.

While getting my truck's annual safety inspection at my friends garage,
I happened to mention to him that occasionally I notice a slight miss in the engine. (I didn't even think it was that bad)
He said "Let's take a look".
He had an old spray bottle containing water. He dimmed the garage lights, raised the hood, started the engine, and sprayed a light mist in the air above the engine.
Man it looked like the 4th of July with sparks arcing everywhere while the engine continued to run smooth.
We replaced the spark plug wires and no more arcing and no more miss.
Never tried it on a small engine, but maybe???