Petrol pump on 1978 Wheelhorse tractor Model C 121 8 speed

[keith-durston]

I have owned my Wheelhorse for 15 years and use it for the purpose it was designed for rather than taking it to shows. It has been serviced by the same outfit for all this time but the mechanic at the company has recently changed and my tractor has come back not working with the suggestion that it is only good for breaking. I disagree with this and want to keep it going. They have tried to fit a new petrol pump which is different to the original one previously fitted and apart from plumbing it in the wrong way round I don’t think they fitted it correctly to be driven by the “blade” on the underside of the big end. It may not even be the correct pump. I have attached a photo of the pump and wondered if anybody can identify if it is correct. My engine is a Kohler 12hp 301 AS.
Hope somebody cann advise me please.
Keith

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[urbanalfa]

This looks like one of the plastic Chinese fuel pumps available on a well known auction site. I can’t advise which fuel pump is correct for your engine, but it should be possible to test if the pump is working by manually using the lever while it’s not fitted to your machine.

If possible, I’d recommend getting the original fuel pump back from the mechanic and taking it apart swapping the new diaphragm into the old fuel pump body. It’s usually the diaphragm that fails and the diaphragm in the new pump should fit into the old pump.

[keith-durston]

Thanks urbanalfa. I know the new pump works out of the engine which is how I identified that it was plumbed in the wrong way round but I am not sure if the blade on the underside of the big end cap is reaching the drive arm and unless I take the engine out and take the sump off I can’t see. That is why I hope someone who knows the engine might be able to identify if my new pump is the right one. I have asked the company if I can have my old pump back but I fear it might have been junked already.
Keith

[charlie]

Having the manufacturers service and parts manual may help. I have found a link to the service manual for the K301 and the Kohler website lists parts lists for the many applications these engines were used for. You will need engine number by the look of it.

[davidbliss]

Unless its worn out every where else its worth repairing, the pump would not be worked by the big end dibber, would have thought off the camshaft, I get really cheesed off with peoples attitude nowadays, many new things you take them out of the packaging use a few times and they’re scrap. Yesterday helping my daughter took my three chain saws all old thirty – forty years old plus but good quality all had been scrapped because of minor carburettor issues and other things fixed and never had one give trouble since, after taking down a large Chestnut tree in November that was easy, I chickened out for one smaller rotten overhanging one with bad knees and having to work part off a ladder got the professionals that soon had it down, like me they had chainsaws from small to large but not as old, talking to them about the chain saws they said had two fairly new saws all dead with issues because of electronics controlling fuelling, WHY as a good quality carb will give years of trouble free use. Today to be green engines seem to be made to use more fuel and fail with electronic issues, for over a year had issues with a new V twin Briggs & Stratton, supposedly emission complaint it drinks petrol, soots one plug and burns the other white and has now gone back twice, Idiots says it runs within Parameters? so I have been having same issues with inability of people to fix a simple thing. Going west got feed back to say with the coils having auto advance electronic advance one coil must have had a fault.

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[keith-durston]

Thanks Charlie. I already have the manuals but sadly the info on the fuel pump is limited and no good diagrams that I can find.
Thanks also David. I am with you on this issue. The old girl should outlive me if it is properly maintained. I still have my first car on the road which I bought in 1964 and that is now 94 years old. My last two modern cars had to be “thrown away” despite being in good mechanical order and both looked pretty much brand new but they both had minor electronic issues which could not be solved! My newest car is now 24 years old and precedes the era of electronics controlling the car but the electronics just advise. Even with that the other day my dashboard lit up saying “stop the car” because of low oil pressure. There was absolutely nothing wrong apart from a faulty electronic sensor.
Still hoping someone might recognise my fuel pump.
Keith

[alan]

Images and details of the K-series engine fuel pump, also as a PDF:

Usually, to make the images bigger, left-click on the thumbnail as normal then right-click on the opened image and choose ‘Open image in New Tab’ or similar and it’ll open it in a new tab for larger viewing.

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[alan]

The info says to make sure that the fuel pump lever is positioned above the camshaft, and that the correct gasket is used if changing from a metal-bodied to a plastic-bodied pump.

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[keith-durston]

Thanks Alan. That is very helpful. I cannot see the cam through the small aperture that the pump fits into. I assume that it is out of sight below the aperture. If so I don’t understand the fitting instruction to ensure the pump lever is positioned above the camshaft. The new pump I have would not allow the lever to drop down that far out of sight. Is it likely that the driving cam could be so worn that it will no longer drive the pump?
Keith

[alan]

I would assume it means to place the pump horizontally onto the engine rather than in at an angle and then trying to straighten it up. I’ve rebuilt many Kohler engines for our tractors and made sure the pump is square-on when replacing.

I’ve taken two photos of a pump that I replaced. The first photo is a side view showing the lever angle, the second photo shows a shiny spot where the lever has been in contact with the cam.

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[keith-durston]

Thank you Alan. That is really helpful. The cam must be above, not below, the aperture and I now understand the fitting instruction. My new plastic pump has a bent steel U channel type arm and I thought that what I could see through the hole was the blade below the big end cap which would fit into the U of the arm. Your wear witness mark has explained all. I’ll look upwards to find the cam and make sure that I tilt the pump upwards when I re-fit it.
Thanks again.
Keith
P.S. I wish that my tractor looked as good as the photo of yours but now with your help I can at least get mine back to work. 🙂

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