Fuel Pump ?

[SteveH 3]

Hello Wheel Horse Fans:

 

  I am new to the group and just started working on an 856.  It has the old style fuel pump and there is no output.  I took it all apart.  The diaphragm is pretty stiff but no holes in it.  I am assuming it must be pliable. Would anyone know of a source fora new diaphragm or rebuild kit?  I have not been able to find the right one.

B232380 3A

 

Thanks a Bundle

Steve Hecht

 

 

 

 

 

[ri702bill 8,965]

Then and Now Automotive in Massachusetts has them. There was also a Member here on RS selling new ones.

A common problem is the check valves and seats are gummed up - may require cleaning...

A ruptured pump  diaphragm is a big issue - raw gas enters the engine and dilutes the oil. Pull the dipstick and see if it smell like oil - or gas.

Edited March 24 by ri702bill

[ebinmaine 70,704]

43 minutes ago, ri702bill said:

There was also a Member here on RS selling new ones.

 

 

@buckrancher

 Brian.  

 

Send him a PM.  

 

[Achto 28,764]

Here are some other sources for rebuild kits.

 

https://isavetractors.com/fuel-pump-diaphragm-kit-for-kohler-k-m-series-metal-body-mechanical-fuel-pumps/

 

https://www.then-now-auto.com/product-category/fuel-pump-kits/kohler-fuel-pump-kits/

 

One other option is to switch to a low pressure electric fuel pump.

https://www.amazon.com/Universal-Electric-HEP-02A-Motorcycle-Carburetor/dp/B0C4XB1232/ref=sr_1_1_sspa?crid=3RVSWYUNI0L5G&dib=eyJ2IjoiMSJ9.VMLtK14F6KSLxamAkynnX6FYEX5-bYXkB2UhYdeLVVuauBUJevtqNsTVBs5Ic2OmG_6tlp9bptNWjsO0TmazGOL6NFzyNzlKEuAMebJXEzr0zx960o4vESK_ZmhFhGyxYTFfBJtGowNQS8TriUNTYpXDjUZn3riYEt9870JBSRIJjFZGj0wqYAwqpghNRyIusHBaR2JYHac-wDC8VZGqNi1vU7-6VpS63SLluV3zQPk.VjI7ycmB3D3jf6nFgUyk0KBibd-MJHQ2JzRbP8jVDfA&dib_tag=se&keywords=low+pressure+electric+fuel+pump+12v+for+carburetor&qid=1742494436&sprefix=low+pressure+electric+fuel%2Caps%2C104&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

Edited March 20 by Achto

[Handy Don 13,340]

When installing the new diaphragm, remember that its job is to flex but not to stretch. It’ll seem too big when properly positioned on the holes for closing the two halves of the pump but the edges will “scrunch down” and seal allowing the “slack” in the middle to move up and down easily with the plunger. 

Edited March 20 by Handy Don

[kpinnc 13,720]

2 hours ago, ri702bill said:

A ruptured pump  diaphragm is a big issue - raw gas enters the engine and dilutes the oil. Pull the dipstick and see if it smell like oil - or gas.

 

When in doubt, just change the oil. Better safe than sorry. 

[rjg854 11,879]

You'll definitely know if you have gas in the crankcase all you have to do is check the oil level. I've been there 😂   I always check the oil level before starting an engine.

[WHX?? 50,702]

It has not been mentioned here yet but there are the cheap plastic replacements. It's been hit n miss tho if you get one that works and stays working . 

[SteveH 3]

Thanks to all those that responded to my request.  I am looking forward to getting the ole WH running again.  It was gummy in the two seat dept. probably from old gas.  

[ebinmaine 70,704]

24 minutes ago, SteveH said:

gas

 

Do your best to get NON ethanol.  

[Handy Don 13,340]

4 hours ago, ebinmaine said:

 

Do your best to get NON ethanol.  

“Non” can lessen the headaches of “carb pebbles” but if pump gas isn’t allowed to sit long enough to attract moisture (i.e. use it up or get it out!), it’s fine. 

[WHX?? 50,702]

Might be worth mentioning before you put it back together glass the halves the same way one would glass a head. 

They can get distorted and leak.  Don't overtighten the screws. I think it was either @Handy Don or @ri702bill said one can distort a diaphragm by overtightening. 

I'll buy that I've had  my fair share of leakers.  

[Wheelhorse#1 1,761]

11 hours ago, ebinmaine said:

 

Do your best to get NON ethanol.  

I just started using it on all my small engines.

Five gallons for around $15 bucks.Maybe it’s just me but every thing seems to run better too.

[WHX?? 50,702]

5 minutes ago, Wheelhorse#1 said:

Five gallons for around $15 bucks

That's a great price. 

[Handy Don 13,340]

On 3/21/2025 at 9:10 PM, Wheelhorse#1 said:

I just started using it on all my small engines.

Five gallons for around $15 bucks.Maybe it’s just me but every thing seems to run better too.

Non-ethanol at this end of the country is usually 91 octane which, if our little “L” head engines ran at high compression, would help out! 

But the main benefit is that pure gas has more energy content than gas with ethanol in it. If you use it in your car/truck you’ll notice slightly higher miles per gallon. 

[ebinmaine 70,704]

44 minutes ago, Handy Don said:

Non-ethanol at this end of the country is usually 91 octane which, if our little “L” head engines ran at high compression, would help out! 

But the main benefit is that pure gas has more energy content than gas with ethanol in it. If you use it in your car/truck you’ll notice slightly higher miles per gallon. 

 

 

There's another thing that shouldn't really exist at this point but still does.

 

As far as I know, all of the new fuel pump and carburetor rebuild kits and fuel lines should be ethanol resistant. I have heard of several instances where something gets rebuilt or replaced and in a very short time there is little bits of rubber in the bowl.

[ET160 30]

I did mine the other day (B-80) with the isavetractors part. 

 

It was gummy and dirty inside. It was good to refresh.

 

I was wondering about the little flying-saucer valves inside.  Is there a source for those?

[ebinmaine 70,704]

5 minutes ago, ET160 said:

I did mine the other day (B-80) with the isavetractors part. 

 

It was gummy and dirty inside. It was good to refresh.

 

I was wondering about the little flying-saucer valves inside.  Is there a source for those?

 

 

The only possibility I'm personally aware of might be

Then and Now Automotive in Massachusetts

[HyperPete 486]

I saw, elsewhere, something about a block-off plate when switching to an electric pump. 

Is this necessary, or just for aesthetics?

[pfrederi 18,324]

2 minutes ago, HyperPete said:

I saw, elsewhere, something about a block-off plate when switching to an electric pump. 

Is this necessary, or just for aesthetics?

I have just left old pump on tape over the inlet/outlet...no problem.  Also made a cover plate not hard and you can buy them from Kohler.

[HyperPete 486]

1 minute ago, pfrederi said:

I have just left old pump on tape over the inlet/outlet...no problem.  Also made a cover plate not hard and you can buy them from Kohler.

I have steel & aluminum.  I can make a plate, but I figured doing what you did should be fine.  I just wanted to confirm that the diaphragm wouldn't rupture and allow oil to leak without gas to cool it.

[pfrederi 18,324]

Just now, HyperPete said:

I have steel & aluminum.  I can make a plate, but I figured doing what you did should be fine.  I just wanted to confirm that the diaphragm wouldn't rupture and allow oil to leak without gas to cool it.

The oil that may splash up against the ruptured diaphragm isn't really going to go very far will just drain back down

[HyperPete 486]

Ok, I found the mechanical fuel pump was not working.  I took it apart and the diaphragm looked good. I decided to go with an electric fuel pump, and got the the cheap chineseium pump that was discussed earlier and or elsewhere. 

https://a.co/d/dRdu7SM

 

I mounted it directly below the carb, where the mechanical fuel pump was, modified to fit the bolts from the old fuel pump, and atop a blockoff plate I made.

 

The engine started right up, but then gas started pouring out of the carb. Since I had removed the needle clip earlier, I put that back, and I confirmed that with the float down I could blow through the intake. With the float up, nothing would flow.

 

I'm not sure why this is occurring; is it possible that mounting the fuel pump so close to the carb could have any impact? Should it be mounted back by the fuel tank? It is obviously overpowering the needle valve.

 

This isn't my first carburetor rodeo, so I'm a little confused.

Edited April 11 by HyperPete

[ebinmaine 70,704]

Might be too powerful or have a poorly regulated regulation regulator. 

 

 

[HyperPete 486]

Shoot!

The threads I read said 3# is a good target pressure. This is supposed to be 2.5 to 4.

Is there such a thing as a passive fuel pressure regulator, such as a small restrictive fitting?

 

I hate to keep throwing money at this thing without a rototiller.  If I can't find one, it's pretty much useless to me. 🥺

 

I could always put it on the 1-0440, but I believe that if it ain't broke, don't fix it!