K321 engine running rough

[ottsm 23]

When I started my Wheel Horse tracker up this year I noticed it was missing sometimes, I went ahead and went through two mowings and gradually it got slightly worse.  I checked the normal things, oil level, adjusted the jets on the carb., etc. but nothing seemed to improve things.  Then yesterday it got really bad with missing and wanting to stall out.  Finally had to stop and start trying things out.  I spraying starter fluid in the carburetor and it did absolutely nothing.  I set the jets back to the suggested starting positions, that did nothing.  At low idle the engine runs like it should but missing just a bit, when it gets past half throttle things start to sputter and misses more to the point that it backfires (I removed the muffler so the points cover could be removed).  Next I pulled the spark plug, I had actually pulled it before and it was cleaner than what it is now, currently black carbon is all over the spark plug.  I disconnected the spark plug and ran it then pulled it right away, no signs of wet gas on the plug.  Next I checked it for spark by pulling the spark plug and grounding the base and cranked the engine, spark was OK.  I checked the gap on the points, points do need replaced and the condenser is probably bad as the points where arcing but still had spark at plug so I don't think that is the main problem.  Next I disconnected the fuel line right at the carb., gas started coming out right away.  Also loosened the bottom bowl on the carb and gas started coming out.  Appears I'm getting fuel to that point, I did not pull bottom off completely because of all the dirt around the engine so I couldn't check if the float was stuck.  I didn't check the timing either because the strobe light is at another location at the moment.  I did put a drop of oil on the points push rod, this did nothing and the push rod seems OK while rotating the engine by hand.  

 

I noticed that I can by a new carb for about $25 bucks, I thinking of getting one.  I'm going to also get a new spark plug, condenser and points.

 

Anyone else have any ideas?

 

[oldredrider 2,547]

You answered your own question. Replace the points and set to .019. Replace the condenser (in my opinion, that's the problem). Also make sure the condenser is well grounded.

The new spark plug can only help. Make sure it is gapped properly; .035 for battery ignition, .025 for magneto ignition. 

Once you know the ignition system is right, you can move on to the fuel system.

Edited May 9, 2018 by oldredrider

[Achto 26,440]

My 1076 would not run good past 1/2 throttle. I chased the fuel system all over the place with no results. Changed the condenser and solved the problem.

[ottsm 23]

Thanks all, I'll start with the ignition first.

[cafoose 3,135]

3 hours ago, ottsm said:

I spraying starter fluid in the carburetor and it did absolutely nothing.

Most often that indicates an ignition problem

[953 nut 51,382]

I agree that an ignition tune up may be needed. Also the fuel system could probably benefit from some servicing especially if ethanol gas has been used. To find non-ethanol gas near you go to this site, https://www.pure-gas.org/

[ottsm 23]

Like the map that shows all the ethanol free gas, didn't know we could even get such gas anymore. 

[rmaynard 14,851]

1 hour ago, 953 nut said:

To find non-ethanol gas near you go to this site, https://www.pure-gas.org/

I've always had to drive 20+ miles to get ethanol-free gas, so I checked this list and it said that my local Kubota dealer was now selling it. I remember when this location was a Buick dealer, and he had gas pumps in back of the dealership, so I figured he was selling bulk fuel. He's only 3 miles away.

So off I went only to find his ethanol-free gas is sold in 1 quart cans for $7.50.

 

Point is, check first before you drive and find out if they only sell the small cans or if they actually pump it.

 

[peter lena 8,031]

11 hours ago, ottsm said:

When I started my Wheel Horse tracker up this year I noticed it was missing sometimes, I went ahead and went through two mowings and gradually it got slightly worse.  I checked the normal things, oil level, adjusted the jets on the carb., etc. but nothing seemed to improve things.  Then yesterday it got really bad with missing and wanting to stall out.  Finally had to stop and start trying things out.  I spraying starter fluid in the carburetor and it did absolutely nothing.  I set the jets back to the suggested starting positions, that did nothing.  At low idle the engine runs like it should but missing just a bit, when it gets past half throttle things start to sputter and misses more to the point that it backfires (I removed the muffler so the points cover could be removed).  Next I pulled the spark plug, I had actually pulled it before and it was cleaner than what it is now, currently black carbon is all over the spark plug.  I disconnected the spark plug and ran it then pulled it right away, no signs of wet gas on the plug.  Next I checked it for spark by pulling the spark plug and grounding the base and cranked the engine, spark was OK.  I checked the gap on the points, points do need replaced and the condenser is probably bad as the points where arcing but still had spark at plug so I don't think that is the main problem.  Next I disconnected the fuel line right at the carb., gas started coming out right away.  Also loosened the bottom bowl on the carb and gas started coming out.  Appears I'm getting fuel to that point, I did not pull bottom off completely because of all the dirt around the engine so I couldn't check if the float was stuck.  I didn't check the timing either because the strobe light is at another location at the moment.  I did put a drop of oil on the points push rod, this did nothing and the push rod seems OK while rotating the engine by hand.  

 

I noticed that I can by a new carb for about $25 bucks, I thinking of getting one.  I'm going to also get a new spark plug, condenser and points.

 

Anyone else have any ideas?

 

 

[peter lena 8,031]

have experience with those carbs, they are NOT built to a us standard, kind of a combination of metric and something else. that gives you the problem issues in trying to tune it, the reaction is not there . if you can, make sure that the carb you buy has US standard jetting in it , you will pay extra  for it , but its worth it. I had a trouble with mine , went after every detail, would not react properly to any setting or adjustment. after giving it a serious talk, I said to myself, self why not try an old main jet  from the old carb? yup that did it. I agree that the point setting is vital, when ever I have an issue , especially  wiring , or carb work  I take the time to detail it, and that usually gives me long term use. Pete

[richmondred01 2,202]

Some people seem to like the 25.00 Chinese carbs. I think they’re trash. When I rebuild engines I never reuse rods, pistons, rings, gaskets they all go into the trash. Same with the Chinese carbs. I’ve thrown 5-6 of these carbs into my scrap metal pile. 

 

[incabman 16]

My vote is also for a bad condenser. Those buggers can simulate all kinds of electrical and seemingly fuel problems. They have given me fits more than once while chasing down issues with the K engines. I have been adding MMO to the fuel I use in my small engines for the last 15 or so years and virtually eliminated any fuel systems problems. Whatever is in the stuff works. No varnish buildup or fuel going bad on me even when left in the tank over winter.

[ottsm 23]

Ordered new spark plug, condenser & points yesterday.  Should come in before the weekend so I'll know soon enough if it the ignition system.  Guess I'll try the rebuild kit for the carb given the comments above.  The current carb is the original with the adjustable jets versus the fixed. 

Edited May 10, 2018 by ottsm

[WHX?? 46,633]

I'll beg to differ with Richmond on the cheap carbs... I have used a few with great success. Sure ....would have liked to use the OEM if it was serviceable but in a pinch for the money?? Sure ..I'm not gonna rebuild one but if you get a year or three out of it it owes you nothing, yeah then is the scrap pile. Let us know if the ignition work solved the problem. 

[953 nut 51,382]

I will second what Jim said, the one I bought is great. The one thing you need to check out is the choke hook up. If I my computer rather than this IPad I could send you a link.

[ottsm 23]

Update, got parts today.  Of course I didn't take the time to change one piece at a time since I figured they all needed changed.  Put it simply the problem is fixed so it was the ignition.  I did test the condenser afterward, I used a good old fashioned capacitor tester (one of the ones with the green eye) that has a leakage tester.  I'm not sure what value I'm suppose to get but I was reading 0.2 uF and at 50VDC it passed the leakage test.  What I did notice about the condenser was when I went to take off the old one, the mounting screw was loose.  Also when I went to put the new one on, the screw is turning on the inside captive nut and cannot be tightened fully.  The contacts are badly pitted from the fact that the condenser was probably out of the circuit from the loose screw, I hadn't noticed it when I was troubleshooting and it may have been shaking from the vibration of the engine.  I still need to take off the sheet metal fan shroud and fix the nut that holds the coil and the bracket for the negative side of the condenser.  For now it appears tight enough to show that the problem is fixed.  I might stick the old spark plug back in just to see but for now it's fixed and I'm happy again.

[953 nut 51,382]

29 minutes ago, ottsm said:

it's fixed and I'm happy again.

                                                

[oldredrider 2,547]

As you found out, a poorly grounded condenser acts just like a bad condenser. Glad you fixed the problem and followed up with the results. Should help others in the future.