K181 Fuel Pump

[Simplecity 22]

Good Day All

  My recently rebuilt K181 in a 857 tractor sputtered and died. Would start and run (sort of ) with full choke, but it wouldn't run long.

  Troubleshooting led me to fuel, so I rebuilt the carb. Reinstalled started right up but sputtered and died repeatedly. Removed the fuel pump and to my surprise, there was no actuating arm. Apparently it is now resided in the crankcase. Keep a spare (metal) pump for the K301 (Raider 12) . Bolted it up, cranked it over, no fuel being discharged. 

  Goggled the pumps and apparently the actuating arms are different. All I see out there are the composite plastic pumps. Anyone have a metal bodied pump that needs a new home? I have no problem rebuilding one if it needs it.

  Thanks for your time

     Simplecity

[wallfish 18,242]

If that arm disappeared --- it went into the crank case. Better get it out before trying to start it again or you'll be rebuilding it again. 

I'm assuming you rebuilt the engine and would have seen / noticed if it was actually a manual pump with an arm on it or vacuum pulse pump, which does not have an arm. A vacuum pulse pump can be rebuilt with a new diaphragm if that's the case

[squonk 43,939]

Vacuum pump. No arm like John said.

[ri702bill 9,533]

Or, you could go the low pressure electric fuel pump route.... Metal body OE pumps are getting scarce and tend to hoarded... All too many of the cheap plastic body units are garbage.

[953 nut 60,348]

10 hours ago, Simplecity said:

My recently rebuilt K181 in a 857 tractor sputtered and died. Would start and run (sort of ) with full choke, but it wouldn't run long.

  Troubleshooting led me to fuel, so I rebuilt the carb. Reinstalled started right up but sputtered and died repeatedly. Removed the fuel pump and to my surprise, there was no actuating arm.

Please don't jump in replacing parts that may not be the problem, that can be a waste of time and money.

When troubleshooting you need to begin at the source (the fule tank in this case) and find out what you have and what you don't have.

With the fuel line removed from the tank do you have flow when the valve is opened?

Is the rubber hose from the tank to the fuel pump in good condition?

Is the fule filter in good condition?

With the tank valve open is there good flow to the fuel pump?

With the outlet line from the fuel pumt to carb. disconnected is fuel flowing without the engine being turned over? Could be a bad valve in the pump.

When the engine is being started is there strong fuel flow from the fuel pump?

IF the fuel pump needs to be rebuilt a kit can be purchased from Then and Now. Call them so you can tell therm what fuel pump you have and get the correct kit.  https://www.then-now-auto.com/kohler-fuel-pumps-2/

 

[Simplecity 22]

13 hours ago, wallfish said:

If that arm disappeared --- it went into the crank case. Better get it out before trying to start it again or you'll be rebuilding it again. 

I'm assuming you rebuilt the engine and would have seen / noticed if it was actually a manual pump with an arm on it or vacuum pulse pump, which does not have an arm. A vacuum pulse pump can be rebuilt with a new diaphragm if that's the case

 I was not the rebuilder unfortunately. Looking at the pump, I do not see any evidence of an arm being there. I ASSUMED there was as that is how my 301 pump works. Again, Im ASSUMING that  the pump works off of crankcase pressure/vacuum.   

[rjg854 12,249]

My Commando 8 and 854, both have vacuum fuel pumps, in other words no arm. Like John and Mike posted, neither does yours, most likely.

[Gasaholic 304]

5 hours ago, Simplecity said:

 I was not the rebuilder unfortunately. Looking at the pump, I do not see any evidence of an arm being there. I ASSUMED there was as that is how my 301 pump works. Again, Im ASSUMING that  the pump works off of crankcase pressure/vacuum.   

1) the vacuum type pulse pumps (look identical to the mechanical pumps outside, but do not have the "hinge pin" for the pump arm) - they do indeed work off crankcase pulses (caused by the piston moving up and down, regulated by the crankcase breather) 

2) If you put a 10-12-14 HP fuel pump on that and hoped it would work , then you may want to avoid trying it any further - The mechanical arms of the pumps are different between the 8 HP and the bigger engines (the 8 HP and smaller have an offset arm) so a) count yourself lucky if you didn't damage the working mechanical pump (any luck and it just rode the camshaft where there's no cam for the pump) and b) with any luck, installing and bolting down the working pump into that 8 HP didn't hurt the 8 HP Camshaft (if your luck is like mine, you may have cracked the camshaft and if that happens, and cam has enough end play or eventual wear, your valve timing goes off kilter because it'd have broken in between the intake and exhaust lobes...)  We had an engine once into the shop I worked at where that happened - owner tried to DIY his own fuel pump fix an didn't get the pump installed correctly. He eventually confessed that he did hear something go "snap" when he tightened down the fuel pump bolts.  Had to tear down & rebuild the engine and replace that broken camshaft... (and his original problem was not even the fuel pump to begin with - he simply forgot to turn the fuel shutoff back on!)

 

Edited August 1 by Gasaholic

[wallfish 18,242]

6 hours ago, Simplecity said:

 I was not the rebuilder unfortunately. Looking at the pump, I do not see any evidence of an arm being there. I ASSUMED there was as that is how my 301 pump works. Again, Im ASSUMING that  the pump works off of crankcase pressure/vacuum.   

Not a big deal as we all assume stuff and that's how we get started on what to fix. So most likely no arm lost inside. That's good. 

Open that pump. Cleaning the check valves inside and a new diaphragm should fix that old metal pump. If the old diaphragm is stiff it will have trouble flexing enough from the vacuum pulse to pump fuel.

In the meantime you could gravity feed fuel directly to the carb just to verify it's running properly. An 856 tank is higher than the carb so you could run it that way but it would starve for fuel going up a hill. Go backwards up the hill and will stay running.