K321 Misses

[bmsgaffer 2,043]

I took a video of my K321 running. I have been doing mechanical improvements to this tractor and this is the one I can't nail down. It runs great, but will miss and stumble pretty constantly. It does loose power, but seems like it catches back up very quickly then does it again.

 

Hitch: It works great under load of a mower (or I don't notice it anymore anyway). It could be unrelated, but it wants to stall when loaded traveling across a 'left-leaning' slope.

 

Also, it seems like the high speed needle is not doing much. I can turn it 3-4 turns and generally not affect how the engine runs. On my other equipment I am used to 1/8 turn making a big difference. No smoke and the exhaust doesnt glow so I can only assume the mixture is somewhat close.

 

Replaced with new: Coil, Condenser, Plug, Entire Carburetor

Swapped from other stock (without affecting problem): Plug wire, points, fuel pump.

 

At the moment I have added an electric fuel pump in line with the existing mechanical fuel pump. I don't know if I am causing problems by doing this, but it was easier than draining the carb and lines again to bypass the fuel pump. I am planning on eventually going with electric only and plating off or bypassing the fuel pump.

 

I need to measure the voltage on the coil to make sure its not dropping out (wiring) but when I put my meter up to the coil it goes bonkers from the EMI and resets (and I thought it was a good one!).

 

Anyone have anything else I should look at?

 

 

[slammer302 2,154]

I'd hate to say it but sounds like carb problem probably worn throttle shaft I've been dealing with the same problem on a c-121 my dad uses at the lake another carb and a rebuild kit and it's running pretty good now

[bmsgaffer 2,043]

I'd hate to say it but sounds like carb problem probably worn throttle shaft I've been dealing with the same problem on a c-121 my dad uses at the lake another carb and a rebuild kit and it's running pretty good now

 

Thats what I thought at first, so I bought a whole brand new chinese carb and it did not help the problem very much.

 

Come to think of it though, I reused the old gasket for the carb because I didnt realize the new carb came with one. Could that cause this issue?

[slammer302 2,154]

Yes it could if its not getting a good seal it could suck air past the carb.

Does it run better if the high speed needle is almost screwed shut?

[WH nut 553]

Sounds like a lean miss to me. Sucking unmetered air.

[Fordiesel69 226]

Sounds like a lean miss to me. Sucking unmetered air.

 

+1

[squonk 38,989]

Just for the heck of it, Make sure your not loosing 12v to the coil. I had a C-145 that started to run like that. Thought it was fuel. Replaced everything didn't run ant better and eventually got worse to the point it would shut off and quit. I founfd a bad fuse holder in the wire harness and a bad connection at the ammeter and it fixed it.

[Fordiesel69 226]

Come to think about it, my C-121 ran like this after I rebuilt the engine.  I forgot to tighten a ground wire, and being the engine is rubber mounted, it does not get its ground path thru the engine bolts like on other models.  When the PTO is enguaged, it moved the engine enough to make my loose ground wire make good contact.  Its definatly worth checking.  Maybe add a temporary ground.

[leeave96 487]

Another thing to check is the timing. Use a timing light to set it. To see the timing mark, I think it's "S"' take a q-tip and dip it in some white paint. Put a dab on that mark and you can see what you are doing with the timing light.

[Fordiesel69 226]

Set points to .018 - .020 and it will be fine.  Time afterwards with a light to get it perfect.

[bmsgaffer 2,043]

Replaced the carb gasket, that did not help.

 

Timing is good to go, replaced points, coil, plug, plug wire, air filter. I looked into all electrical connections I could find and haven't found one that helps the problem yet.

 

I have yet to take the head off, but that is my next order of business.

 

Could this be a head gasket problem? I did not adjust the float, could a poorly adjusted float cause this? (seems unlikely since replacing the entire carb did not help)

 

If I run too long or hit a bump while on a slant (left side down) it nearly kills it, cant tell if its a flood or electrical.

 

This problem is non-existent for the first minute or two of running the engine, and is definitely more pronounced when the engine is hot.

Edited June 23, 2014 by bmsgaffer

[squonk 38,989]

If you have an ammeter, Check the connections to it. I have seen 3 tractors in the past year have running problems and those connections were the cause.

[Crabtreeb 8]

Did you ever find the answer to this problem I am having the same problem.

[bmsgaffer 2,043]

I have not yet found the answer. I am hoping to dig into it further, but I might not get to do much until next week. Im down to: electrical problem that I can't find, float adjustment, headgasket or other internal problem.

 

I think...

 

  Its buggin me to death, I just want a smooth running Kohler.

[Crabtreeb 8]

Thanks for replying I am rebuilding the head on mine so I will let you know if that resolves the problem.