Fuel pump

[markseven 85]

Mine fuel  pump is  leaking around the gasket  it original .

Tried tighten the screws still leaks .

Do not want to buy an aftermarket one.

Are they rebuildable and where to get the parts?

[ri702bill 10,982]

What engine exactly?? Different engines, different options.

[Achto 30,490]

https://www.amazon.com/Ciuouient-230675-Diaphragm-Rebuild-Compatible/dp/B0F1XYDS4B/ref=sr_1_4

[markseven 85]

Its a kohler k301 12 hp

It always starts and runs good 

But it always takes some time cranking it over before it fires.

I ordered the kit hoping it helps. 

Thank you. 

[Achto 30,490]

8 hours ago, markseven said:

I ordered the kit hoping it helps. 

 

If this does not fix your issue, then you might consider switching to an electric pump. They usually render faster cold starts.

 

https://www.amazon.com/Electric-Universal-Pressure-Transfer-Carburetor/dp/B08PY7V2MM/ref=sr_1_4_pp

[WHX?? 53,765]

12 hours ago, markseven said:

ordered the kit

For the short money they are I keep one on the shelf. If the pump isn't too gunked up and check valves are good no need to buy a pricier then & now kit. 

 

I like to glass the pump halves as they can warp from over tightening. That said don't over tighten on a rebuild.   

[kpinnc 16,634]

23 hours ago, WHX?? said:

like to glass the pump halves as they can warp from over tightening. That said don't over tighten on a rebuild.   

 

Just did the same on mine. Prolly gonna be next week before I order a kit. Complicated for what they are...

 

 

[markseven 85]

It starts insanity now with the new 

Diaphragm. 

Only problem is it still leaks .

 

 

 

[markseven 85]

On 1/4/2026 at 9:44 PM, WHX?? said:

For the short money they are I keep one on the shelf. If the pump isn't too gunked up and check valves are good no need to buy a pricier then & now kit. 

 

I like to glass the pump halves as they can warp from over tightening. That said don't over tighten on a rebuild.   

Still leaks the diaphragm i ordered

Wasn't exactly the right one.

I had to slightly oblong the holes in 

The gasket in order for the four 

Bolts to go thru.

Maybe this is causing the leak.

What to you mean by glassing the two

Halves?.

[pfrederi 19,501]

Fine emery cloth  or wet dry sandpaper on a sheet of glass.  Rub the pump mating surface on it

[sqrlgtr 1,798]

Just according to where you get the diaphragm from, some are pretty thin. The last one I done leaked so I made a gasket that goes between diaphragm and pump body, took care of leak so far. Used the rubberized gasket making material. The diaphragms isavetrctors used to sell were superior to others I've had and did not require a second gasket. I wish I knew where he sourced them from.

[Handy Don 15,650]

57 minutes ago, markseven said:

I had to slightly oblong the holes in 

The gasket in order for the four 

Bolts to go thru.

The holes were correct originally. The correct install “scrunches” the diaphragm to provide slack for the pumping action. This is done by manually holding the pump actuator lever so that it is pulling the diaphragm. While holding, successively adding tightness (i.e. not all at once on each screw) squeezes the seemingly excess material evenly.

A taut diaphragm install causes poor pumping and early diaphragm failure. 

 

Glassing as noted above. 

Edited Saturday at 07:12 PM by Handy Don

[sqrlgtr 1,798]

9 minutes ago, Handy Don said:

This is done by manually holding the pump actuator lever so that it is pulling the diaphragm.

Glad you mentioned that. I really dont see how one would get pump back together without doing that way .

[Retired Wrencher 6,271]

Lots of good info on this post. Good knowledge to know.

[squonk 45,086]

Electric and don't look back. HAPPY MOTORING!! 

[WHX?? 53,765]

3 hours ago, squonk said:

Electric and don't look back. HAPPY MOTORING!! 

Not that I am admitting The Squonky is right but ... yeah some so us are as pure of tractor as we are of mind ... 

 

On 1/10/2026 at 12:14 PM, markseven said:

What to you mean by glassing the two

Halves?.

 

It's a procedure where you have a piece of plate glass with a sheet of say 400 grit or better wet /dry emery paper taped to it. It provides a surface that you can sand the halves flat . Note KP's pic where the half is slightly warped. Glassing removes them. I prefer to do it wet as it floats away particles. 

Same procedure for glassing a head & plenty of you tubes on doing it. 

If you overtighten the the screws it will squeeze the diaphragm too much at the corners leaving a gap where those warped areas are. 

Extreme overtightening can even warp the halves further. 

 

On doing a head  ... same principle 

headgasket.pdf

Edited 11 hours ago by WHX??

[pfrederi 19,501]

I like Electric pumps but I thought I might fix one of the old metal pumps I have.  But then I went to Then and Now and found the kit was $32.50, a bit stiff bit OK  then went to check out....Shipping showed up as $15.25 Priority Mail Flat rate and then another $4.00 for Handling.    I know USPS isn't cheap but on their website Small Flat rate box $12.60 and commercial customers (I would assume that this outfit is big enough to qualify) is $8.75.  

 

Sorry I do not like that  ... back to electric a bit more money for a Posi flo but Carbole which a lot of people here use is only about $25 shipped

[kpinnc 16,634]

I'm a huge fan of electric pumps, so long as they aren't the junk versions. I have several (Facet and Carbole), and they have worked very well. I will use more in the future I'm sure. 

 

My only interest in this mechanical pump is for use on my 701. I'm trying to preserve as much on this single machine as I can. 

 

Nothing else I have is this close to original. 

[WHX?? 53,765]

6 hours ago, pfrederi said:

hen and Now and found the kit was $32.50, a bit stiff bit OK  then went to check out....Shipping showed up as $15.25 Priority Mail Flat rate and then another $4.00 for Handling.

Same here Paul when I only needed the diaphragm so I used Dan's .

I kinda hoard them after all the issues with the plastic ones. 

1 hour ago, kpinnc said:

aren't the junk versions.

Guy has to believe the one in post 6 is junk KP but I pi$$ed a Hamilton away in worst ways  soooo ... so far so good. 

[kpinnc 16,634]

41 minutes ago, WHX?? said:

so far so good. 

 

I gotta get a kit for mine too. It was probably the nastiest fuel pump I've ever seen!

 

We will see how it goes!