K321 missing under load

[Stike 204]

I am currently working on a 1979 k321 that hasn't been started in many years and now have it running but having issues that I haven't been able to figure out, runs okay under no load other than driving with a slight miss but with mower deck engaged it loses power and starts missing no backfire just not smooth and lacks power, I've set the govenor arm replaced and set the points, condenser, coil, fuel pump, fuel lines, coil wire, spark plug and cleaned the carb twice all with the same result,   still thinking it may be carb related but at my wits end (not a long journey it seems anymore) any thoughts would be much appreciated.

[Stepney 2,354]

Did you set the points by gap, or by the timing hole behind the starter? Had a few that were particularly touchy. Is the float height correct, providing tweaking the carb doesn't help?
On a trivial note, tried another plug or two? Is the exhaust plugged?

[953 nut 59,799]

1 hour ago, Stepney said:

Is the exhaust plugged?

That was my first thought. Setting the points with a timing light or Static timing would bee good too.

[oliver2-44 10,691]

Have you checked for air leakage at the carb to block and at the throttle shaft?  With it running spray some carb cleaner in those areas and see if it speeds up.   

The attached thread has the Kohler manual and timing info in case you don't have it.  Your K321 has the ACR cam, so don't pay ant attention to this threads discussion of the smaller engines.  

 

[Ed Kennell 41,802]

All good advice above.

Just be aware, new parts do not always function properly.     I like to switch parts from a good running engine.

Do you have a good spark at the plug?

Do you have a good spurting fuel supply from the fuel pump when you remove the line to the carb and crank the engine.

[Tuneup 1,452]

Go to manual control - does the engine respond under that deck load when you manually increase throttle on the carb top? If so, your governor needs attention. If it hesitates at all, ignition first and then the carb or fuel pump.

[gwest_ca-(File Mod) 11,451]

I have a theory that the valve stems could use some lubrication on older engines especially at idle speeds. Marvel Mystery oil in the fuel does the trick. Have used a shot of 2-stroke oil with the same results.

 

Garry

[Rob R 973]

My two cents once you verify good spark at the plug...... fuel delivery or carb issue(s) you need to go from the tank to the carb (change ALL the lines, filter etc.) then do the same with the carb disassemble soak, take complete apart clean the jets and atomizer then do it again then put it back together....  

[ebinmaine 72,443]

@Stike

Couple things just came to mind.

 

I see it says you've CLEANED the carburetor. Have you SOAKED it in anyting?

 

Maybe the other guys could answer this. I'm not sure if it is a thing..... Is your throttle shaft loose in the body of the carb? Excessive outside air sneaking by?

 

[Stike 204]

Thank you everyone for all the replies this is why I love this site all the helpful and friendly people here. To break down the questions, I set the points by gap (my timing light and several other tools were stolen in a break in to my work shop a while back) float height is correct, tried several plugs, exhaust is clear, no air leaks at carb, all parts were used proven good, has good spark, good fuel flow from pump, have sea foam in fuel for lubrication and cleaning, all new fuel lines and filter, throttle shaft has no slop, manually moving the govenor arm at full throttle does not improve running or power, I have not soaked the carb but think that is my next step, any recommended solution for soaking and for how long? Again thanks so much for the help just want this old girl out working again.

Mike

[ebinmaine 72,443]

Boy it sure does sound like you're headed the right direction. Lots of bases covered.

 

There are quite a few different things you can use as a carb soak. I can't search for well on this phone but there was a thread recently that maybe somebody else could point out.

 

I've been using a Gunk brand gallon can soaking kit for a couple years and I've had good success with it.

Disassemble. Soak for 2 days. Compressed air clean it out. Repeat. Then put it back together. Seems to work okay.

Berryman's is another great brand.

 

Other folks use several other things and also have great success.

 

 

[953 nut 59,799]

   There are some very small passages in these carburetors and unless they are open it will not perform properly.

[Stike 204]

Thank you again for the fast replies, I'll see what my local napa has for carb soak tomorrow, I've brought several of these K series engines back to life after years of neglect and abuse but this one has been a real challenge, but with all your help I'm confident I'll have plenty of seat time for years to come. The best thing is learning new things, like I've always told my kids your memories, friendships and intelligence are the only things that are truly yours.

[moe1965 753]

Keep us informed on what happens.  I'm interested to find out what happens.  I'm not much for voodoo solutions but I had to carb issues cured by marvels mystery oil.  Took about two tank fills but had positive results

[Tuneup 1,452]

You have the know-how so you'll get there. I've had to fiddle with old Japanese motorcycle carbs so it's a matter of patience and repeat cleanings. Have you tried the beer approach yet? Sit and stare at it and go through 1 or 3. Makes things more tolerable. Sorry to hear about the theft. Theft of a man's tools is especially evil.

[ebinmaine 72,443]

3 hours ago, Tuneup said:

Have you tried the beer approach yet? Sit and stare at it and go through 1 or 3. Makes things more tolerable.

 

 

I got to remember that one

[Stike 204]

I'll definitely keep everyone informed on what happens and how, going to pull the carb for another cleaning and soak in the morning although a voodoo cure would be ok at this point, I may have to use the beer approach on this one as just sitting and staring without a beer hasn't been working so far.

[Stike 204]

Wasn't able to get back on this project till today but pulled the carb and cleaned it again and decided to try the pine sol soak after seeing the new carb dip doesn't seem to work like it used to and 32oz pine sol was $4.00 so we'll  see how it goes, I'll post the results to hopefully help someone in the future.