Jump to content

Garden Tractors and Parts on eBay



Photo
- - - - -

'76 has me baffeled


  • Please log in to reply
11 replies to this topic

#1 todapuckett OFFLINE  

todapuckett
  • Member
  • Member No: 83303
  • 16 Thanks
  • 32 posts
  • Location: rougemont nc

Posted April 28, 2017 - 07:18 PM

So, last June I posted about my 76 PK losing power and you guys gave me some great advice and I got her running pretty well by the end of the mowing season and she did well over the winter.  HOWEVER, we are back in mowing season again and I am having issues again.

 

She starts running rough, sputtering and losing power when the fuel tank gets down about 2 inches from full.  I can limp it back to the fuel can and fill it up and she runs fine.  I make a few laps around the pasture and the same thing.  I don't cut it off, so I don't think it is heat, It is pretty amazing, as I fill the tank it smoothes right out.  

 

2 thoughts as I write this.  1) Fuel pump (which I rebult last year) is out/weak and the fuel is gravity feeding until it hits carb level but I think the tank sits higher than that.  I will look at that in the morning   2) The flow through hole in the bottom of the side baffel in the fuel tank is clogged and fuel isn't flowing well once it drops below the top hole.  I cleaned the tank last year, but there is no way to see inside that area.

 

This is the same thing that plagued me all last summer.  Since I was constantly working on it, I never filled the tank because I got tired of draining it.   I have: Replaced the fuel cap, replaced the fuel lines, cleaned the tank and filter, wrapped the fuel lines in aluminum foil to keep from vapor locking, rebuilt the fuel pump, rebuilt the carb, cleaned the cooling fins, adjusted the valves, replaced the head gasket and cleaned the piston, replaced the spark plug and ignition wire, and adjusted the carb many times.

 

When the tank is full she runs like a scalded dog.  Any ideas?


  • classic said thank you

#2 propane1 ONLINE  

propane1
  • Senior Member
  • Member No: 54307
  • 7,858 Thanks
  • 3,825 posts
  • Location: Charlottetown, Prince Edward Island, Canada

Posted April 28, 2017 - 08:10 PM

Try another or different gas tank cap. Sounds like it's slowly starving for air, that gets into the tank to allow fuel to run to carb. Maybe run it wirh fuel cap loose a little bit and see if it changes.
Just a guess,

Noel
  • CRFarnsworth, 637Yeoman and todapuckett have said thanks

#3 secondtry ONLINE  

secondtry
  • Senior Member
  • Member No: 83632
  • 1,183 Thanks
  • 985 posts
  • Location: Washington State

Posted April 28, 2017 - 08:54 PM

If possible remove the fuel line from the carb and run it into a container. then crank the engine to see if the pump will supply a decent amount of fuel to the container. Don       


  • todapuckett said thank you

#4 MNGB ONLINE  

MNGB
  • Senior Member
  • Member No: 62466
  • 1,657 Thanks
  • 1,180 posts
  • Location: Minnesota

Posted April 28, 2017 - 08:56 PM

Hi most tanks have either a sediment bowl with shut off or a brass fitting shutoff that has a finger screen if yours have one or the other have you removed them and cleaned them completely, this could be the problem


  • todapuckett said thank you

#5 chieffan ONLINE  

chieffan
  • Senior Member
  • Contributor
  • Member No: 62695
  • 8,634 Thanks
  • 5,939 posts
  • Location: SW Iowa

Posted April 28, 2017 - 09:08 PM

Had the same situation on a Wisconsin 10 hp  a couple years ago.  Found it was the old paper seal that was in the gas cap that would swell with the gas splashing on it and close off the vent hole.  Cut the hole out larger and never had a problem after.


  • Alc and todapuckett have said thanks

#6 todapuckett OFFLINE  

todapuckett
  • Member
  • Member No: 83303
  • 16 Thanks
  • 32 posts
  • Location: rougemont nc

Posted April 28, 2017 - 09:12 PM

Will try another gas cap, it acts like that may be it although it doesn't smooth out when I take the cap off, just when I actually add fuel to the tank


  • propane1 said thank you

#7 GardnMastr OFFLINE  

GardnMastr
  • Senior Member
  • Member No: 85758
  • 319 Thanks
  • 157 posts
  • Location: Heart of Indiana

Posted April 29, 2017 - 08:18 AM

I always try to cut my problems in two, divide and conquer. Temporarily mount a different tank on your machine, a little higher than the old one. If it has no effect, then it was not the problem. Look for the problem after the tank. If it does have a positive effect, then the problem is related to the tank. At the least you cut what your looking at in half. Best of luck.


  • todapuckett said thank you

#8 lrhredjb ONLINE  

lrhredjb

    Member

  • Senior Member
  • Contributor
  • Member No: 3984
  • 513 Thanks
  • 446 posts
  • Location: Noblesville,IN

Posted April 29, 2017 - 09:39 AM

Are you actually adding fuel to the tank with the engine running? If so I hope that tank is a long way from the hot engine/exhaust/spark plug. That could be a dangerous practice.



#9 todapuckett OFFLINE  

todapuckett
  • Member
  • Member No: 83303
  • 16 Thanks
  • 32 posts
  • Location: rougemont nc

Posted May 07, 2017 - 09:09 PM

So, I mowed again today and had no problems at all.  Didn't sputter once, and the only time I stopped was to check and make sure I wasn't going to run out of gas.  Happy to say I can do the whole pasture on less than a tank of gas.

 

It was conciderably cooler than the past times I have mowed (low 60's versus high 80's/90) so the issue may be vapor lock from fuel boiling in the line,  but I still don't know why topping the tank off would fix that.  I will add a little more aluminum foil around the line to help dissapate heat and see how she does when it gets hot again.  Thanks for all of the input, I will keep updating if things change again.



#10 classic ONLINE  

classic
  • Senior Member
  • Member No: 52970
  • 4,756 Thanks
  • 2,090 posts
  • Location: New York

Posted May 07, 2017 - 09:40 PM

Have you removed the tin covers and cleaned out the cooling fins on the block and head? Air cooled engines can overheat badly if the cooling fins are blocked. You would be surprised at how much oil, dirt, grass clippings, mouse nests, etc. can accumulate in an engine. Remember, the flywheel acts like a giant vacuum cleaner and whatever gets sucked in can get caught up in the cooling fins.
  • Alc, MNGB and todapuckett have said thanks

#11 todapuckett OFFLINE  

todapuckett
  • Member
  • Member No: 83303
  • 16 Thanks
  • 32 posts
  • Location: rougemont nc

Posted May 08, 2017 - 09:46 PM

Classic:  Yes, I did that last summer when I first got her, and again over the winter.  I am in North Carolina, and it does get hot here.  No doubt that is part of my problem, but the amount of time it takes to top off the tank isn't enough to cool down the engine.  Plus, I have purposely kept her idling to eliminate that as well.

 

You are correct about how much gunk gets into those cooling fins though, and I highly recommend everyone keep them cleaned.


  • classic said thank you

#12 todapuckett OFFLINE  

todapuckett
  • Member
  • Member No: 83303
  • 16 Thanks
  • 32 posts
  • Location: rougemont nc

Posted June 02, 2017 - 08:19 PM

Still running fine, even on hotter days.  I am pretty sure the fuel cap wasn't venting.






Top