K301 help please
 

Here's the situation:


I have a replacement 301 that I've never seen run for extended periods of time. I changed the oil, pulled the carb that was on it, and replaced it with a Chinese version to see if the engine was going to run.



This is the engine for the 123 in the other thread. I was firing it up to adjust the hydro/brake linkage and things were going well (we have brakes now for the first time since I've owned this tractor!) but herein lies the current problem:



Engine now starts up but as it warms up, it seems to "fatten up" after 2-3 min and run rich (I think ) till it finally sputters to a stop. It never backfires as an overly leaned out engine will when it craps out.

• Tank is cleaned.
• Sediment filter and housing cleaned
• Carb has been swapped with the original one that came on the engine numerous times (same issue with both carbs)
• Fuel runs freely when I pull the fuel feed at the carb (including immediately after it stalls). It's got gas to the carb.
• Replaced gas tank with tsimple test tank. Same issue resulted
• If I let it sit for 5 min it will start right up, and repeat this cycle.
• Fresh 100% gas
• When running, there's no oil smoke. There's lots of compression.
• When it first starts, it runs well, no missing, etc. at all RPM
• Carb adjustments are at the factory default settings per the manual (both carbs). I've tweaked these as it runs with no change in the end result, so I set back to default settings.
• I can feel a strong stream of air out the front of the head indicating the tins are not plugged up. Engine doesn't seem to be overheated.

I have not done anything with the points/plug other than to check the plug condition (nice white insulator, no soot/oil deposit) when I installed the motor.



I think I have new Chinese carb I could throw at it, but it seems extremely unlikely to me that regardless of the carb, the engine behaves the same way (warm up ok, then start to stumble, then die after about 3-4 min)

Coil?


Condenser?


I do need to check the plug.




Help!



When the engine first started, it would not low idle (engine speed stayed high). I set the governor per the manual and then I had a nice low idle.



I've always thought 90% of small engine problems are fuel problems, and this one acts like it, but I'm at a loss as to what to try.



John

Adjust the points and swap in a known good coil and condenser.

Plug should read Nestles quick brown.:beerchug:

As if choke doesn't fully open when it's warmed up?

Exhaust restriction or blockage perhaps?

Very good comments... let me respond to your inputs:

• Yes, I'll check the plug tomorrow. I should have done it today but I was getting frustrated and know that I should walk away from a project when that happens.
• Yes, it does seem kind of like a choke stuck on in fact. Of course it's a manual choke which I can see is wide open, but it does flatten out like that .
• Exhaust restriction. That's an interesting suggestion. The muffler that is on the engine is one of the large chinese "salt shakers" that you can get from Tractor suppy or ebay or the like. It came this way from the seller . I don't have the original big muffler that the 301 came with (that angles in front of the PTO), but that's a really interesting suggestion.
  
  Anyone else running such a muffler setup on a K301?
  
  
  Here's a picture of the setup
  
  

If you take that tape off the carb it will run better...

Exhaust restriction as in exhaust valve heats up and begins to stick?

Did you pull the head and the valves and decarbon?

I knew it was something simple! :-)

If only...........


Anyone ever run this kind of muffler successfully on something bigger than a O?

I wish I had a grand solution for you but I do not.
I do however want to commend you for learning the skill of
walking away when it gets frustrating. I have solved more problems
walking away and thinking then fighting something.
You will get it solved there is no doubt.

Ken

Check your points for pitting and burns, and indication that your condenser is going bad. If the points look good swap the coil for a known good one and see what happens.

Thanks.
 

Thanks for the ideas. I'll start with plug/points/coil/condenser/timing as they're all overdue anyway. There's always a danger of changing stuff and introducing additional problems, but I'm convinced that fuel probs are not at the root of this, so off we go.



The exhaust valve is a possible, but would involve breaking off head bolts, installing helicoils and the like and I'm not there yet, and Occam's Razor usually applies to mechanical stuff too.

I've noted the dipstick stop is loose. Will have to go look at my other 123 and determine the right position for it.

Found it!
 

Stepping away was the right call.

I took the Little Red Smoker (782D) to do lawn work, then went back to the stubborn 123.


First thing to check: Spark plug color. Guess what was only in finger tight?


(It runs well now, though it surges and surges , so I've got to mess with the governor stuff some). Not a puff of smoke though and it runs very smoothly for a 50 yr old engine.

Thanks for helping me think out loud till I got the answer.


John (the blind squirrel)

Glad you got it figured out :beerchug: Finding plugs only finger tight reminds me of doing the plugs on my girlfriend’s 97 F150 with the 4.6. Almost every plug was barely tight. Ran fine, but must have been real close to putting 8 fresh speed holes in the hood :biggrin2: