Kohler Engine Fuel Pump

[bdoss2006 1]

I have an 8hp kohler engine (K181 I think?) on a wheelhorse. I have had trouble with the fuel pump leaking multiple times for years. It appears to have the original fuel pump. Before the latest repair, it was literally spraying gas from where the two halves come together with every stroke. I bought this rebuild kit 

 

https://isavetractors.com/fuel-pump-diaphragm-kit-for-kohler-k-m-series-metal-body-mechanical-fuel-pumps/?gad_source=1&gclid=CjwKCAiAi6uvBhADEiwAWiyRdrPpBDyVjw2MVaZWiG7wUBpNckt6YYYBU0E2MktdS9x0A81LOP-EFBoCY9MQAvD_BwE

 

from Isavetractors, and installed it tonight. The leaking is slower but it sorta oozing as the engine runs. I dont know why it is still leaking. I made sure both sides were clean, and even sanded them slightly with 600 sand paper. Any ideas on what the deal is or how to fix it?

[953 nut 55,813]

When you install the diaphragm in a fuel pump the arm of the pump needs to be pulling on the diaphragm whiler the screws are being tightened to prevent tearing it.

[Handy Don 12,467]

13 hours ago, bdoss2006 said:

... leaking is slower but it sorta oozing as the engine runs. I dont know why it is still leaking. I made sure both sides were clean, and even sanded them slightly with 600 sand paper. Any ideas on what the deal is or how to fix it?

The pump housings are relatively soft metal and all of the three I’ve touched were warped (how? I have no idea).

I discovered this by placing each mating face on a good flat surface and noting that there were gaps that would prevent a tight seal when it was together.

I used @ebinmaine’s head flattening advice to carefully and slowly flatten both faces before cleaning and reassembling.

 

Also, similar to @953 nut’s comment, the diaphragm is NOT intended to stretch to pump fuel. that would wear it out very quickly. During installation, the diaphragm should “pucker” inside the central cavity. You may be concerned about wrinkles at the edges where it seals but these will flatten out as you tighten the halves together. Lastly, make sure to use a criss-cross pattern when tightening each screw a little at time until it's together.

Edited March 9 by Handy Don

[WHX?? 49,171]

Are you familiar with glassing heads? Fuel pump halves need the same treatment. It takes quite abit using 400 grit wet. They distort due to overtightening. Tighten halves just enough. 

Note between the screw holes. Glass until this spots are about gone. 

I've tried extra gaskets, sealer, filing  but this is the only thing that works.  

 

Edited March 9 by WHX??

[pfrederi 17,885]

My solution for leaky mechanical pumps easier and faster...and close in price to a rebuild kit. lasts and lasts no danger of future gas in the crankcase...

 

 

[Marv 943]

27 minutes ago, pfrederi said:

My solution for leaky mechanical pumps easier and faster...and close in price to a rebuild kit. lasts and lasts no danger of future gas in the crankcase...

 

 

  I use the Facet pumps as well. They work well for me. I prefer them to the original pumps

  Marv

[oldlineman 1,482]

I'm also a fan, those e pumps are the way to go in my humble opinion.

[23 Reo 229]

What model posi-flo do you use?

[oldlineman 1,482]

Same as Pfrederi and Marv, a little more money but no problems with them. Bob 

[squonk 41,345]

Napa 610-1051