Kohler K Fuel Pump

[23 Reo 229]

If I remove a bad check valve from my fuel pump will it work if I install an in line check valve?

[Ed Kennell 38,158]

Interesting question.         If the bad valve is on the inlet side of the pump and the new check valve is installed very close to the pump inlet and the diaphram and the pump outlet valve are good, it may just work if you never allow the pump to lose its prime.     Let us know after you try it.      Or just rebuild the pump.

[Achto 27,570]

The only known source for a complete rebuild kit for metal body Kohler fuel pumps.

 

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

[23 Reo 229]

I was curious. I'll give it a try. 

[rmaynard 15,436]

The main thing that I am seeing other than bad diaphragms is that the brass seats are deteriorating. Even with new check-valve discs, they don't seal due to the bad seat. Haven't found a way to fix that issue. Back in the good old days, before ceramic seals in faucets, when they would leak, your plumber would have a valve seat reamer that would resurface the seat. I guess if you have a machine shop you could make something to do the same thing.

[wallfish 16,994]

14 hours ago, 23 Reo said:

If I remove a bad check valve from my fuel pump will it work if I install an in line check valve?

Yes.

The fuel pump requires 2 (good) check valves in order to pump. They need to keep the fuel flow flowing in only one direction.

It'll work even if you don't remove the old one

[squonk 41,079]

I tried 2 of those inline check valves in 2 other applications. Didn't work worth a 

[wallfish 16,994]

 

5 hours ago, squonk said:

in 2 other applications.

What hill were those applications used on? Think you were probably trying to use them to seal a gravity feed of fuel from leaking back down the line. They don't seal well enough for that.

There's nothing spectacular or special about the check valves in a fuel pump. In fact, they don't really always seal all that tight to begin with. Ever see those little springs? BUT, since the pump is creating fuel pressure by the movement of the diaphragm, the valve seal on the inlet side gets pushed closed by the pressure going out and the forward valve opens. When the diaphragm sucks fuel in, it's the opposite and the inlet side opens flow and the forward one gets sucked closed. The pressure created by the diaphragm closes and seals the check valves better than if it was simply sitting there without any of that pressure. Hence the fuel leaks by them and down the fuel line with the engine off.

They do leak a little (like every pump out there does) but the pump will still pump fuel. Some volume of fuel is lost through the leaks but it's still plenty of volume enough going through to run an engine with some to spare.

Moving the check valves from internal to external will still utilize that same effect of the pressure it has on sealing the check valves.

When the leaks get too big the fuel will just move back and forth in the fuel line much more and so less volume and pressure out.

[squonk 41,079]

I used  ( tried) those inline check valves on a 953 and my Power King.

[D_Mac 8,610]

21 hours ago, Achto said:

The only known source for a complete rebuild kit for metal body Kohler fuel pumps.

 

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

Seems you have to take them apart to find out what kit you need? I have the one with the primer lever on it. Like to have the kit before taking it apart. 

[WHX?? 48,815]

You need to take it apart to see if it has the T style diaphragm to lever connection. Most if not all of ours have it. Lever doesn’t matter. 

[WHX?? 48,815]

Not too here but it was suggested to utilize a cheap jungle check valve on 520s or Onans to help keep gas in the carb. Didn't really help. Still have to crank to get gas up except for the converted electric pumps. 

[Ed Kennell 38,158]

1 hour ago, wallfish said:

When the leaks get too big the fuel will just move back and forth in the fuel line much more and so less volume and pressure out.

Yep, same problem with this 80 yo pump in my chest.        All diaphragm  pumps are pretty simple......a couple check valves and a squeeze chamber.