Help for you and me - Kohler fuel pump

[birddog]

A month or so ago I picked up a couple JD 212’s, a 78 and a 83. (for those not familiar with JD’s they have K series Kohler 12 HP engines) Thanks to gas tanks with nothing but water in them, both fuel pumps are bad. (see pic. 1) Being a cheap skate I’m not about to give Deere something in the range of $140 or Kohler about $80 and not even e-bay $30 for new one’s.

So I decided to try a rebuild myself. With both of these pumps, other then clean up, only the check valves were no good. In pic. 2, I show, and more or less explain what I did.

Where I need help is, I need a glue that will not be dissolved by gas. At this time the last washers (part 5) are not quite tight enough of a fit to stay in place. I did put a couple stake punches in the inlet one which probably would be enough to hold it. But on the outlet side staking it was enough to keep the seal from sealing. There was enough room to put a staked second washer though and that may hold. I don’t feel though that they are tight enough of a fit once the engine is up and running, so possibly the need for glue there. I do have an idea to use the outer part of the original check valves though which would probably eliminate the need for glue there. But I would still need glue to fasten the springs to the seals. I’m not sure that they need to be fastened together but on the original check valves the springs are held captive by the metal cage. So I think it probably would be best to do so also.

I have tried the pump by hand, using silicone to hold the parts together and I think it works every bit as good as the original. Of course that could change when installed.

I did think that when compared to the original check valves that the holes in the fender washers may be to small and reduce the flow. So I did some measuring, The washer hole is equal to a loose fit # 22 drill, (.159 dia.) the hose nipples are equal to a loose fit #21 drill, (.157 dia.) so no problem.

Right now I'm waiting for the gas to eat up the silicone so I can experiment with my other idea using more of the original check valve. Hopefully someone can clue me in on some gas proof glue.

(edit; I also posted this on my other favorite site wfmachines.com)

[Eugene]

Your local auto parts store sells fuel pump kits for Kohler engines, including the K301. Also fuel pumps for Kohler engines.

[birddog]

Your local auto parts store sells fuel pump kits for Kohler engines, including the K301. Also fuel pumps for Kohler engines.

I don't think they sell them for less then a dollars worth of parts.

[Jim Becker]

Where I need help is, I need a glue that will not be dissolved by gas.

My first thought was JB Weld. About any epoxy would probably be OK.

[birddog]

Thanks Jim. I had thought about JB weld but it seems to me I tried it once before (I think to seal a gas tank) and it softened up. I suppose though maybe it was mixed wrong or wasn't cured enough when the gas came into contact with it.

[Bob McCarty]

Mark, Several years ago I made a quarter sized wafer of JB that was left over. After letting it harden overnight, I put it in a jar with gasoline that sat on the workbench for most of a year. I would periodically check it and could see no observable change in the surface. I wouldn't hesitate to use JB in a gas environment.

Bob

[birddog]

Thanks Bob.

[birddog]

First an update on pump #1. I decided to try to get by without any kind of glue. What I have done is added a couple more stake punches in the washers. Now they seem to be holding pretty good. The only thing is I tried it with just the single staked washer on the outlet side and the valve seal just doesn't seem to seal tight enough. It pumps good once there's gas in it, but I had to put my finger over the outlet to get it started. I think what I'm going to do is pull it apart and go back to two washers on the outlet side. Also I think I'm going to get two new washers and put them in place and mark them for the stake punches so I can get better placement. I think I'm going to go with four on each side of the washer just to get a little more hold. I also installed another o-ring in each valve, just a bit bigger ID then the spring OD. I think that should help keep the spring centered on the seal, seeing that I'm not using any glue to keep them together.

Here's a picture of the assembled top of the pump. (before my final changes)

[birddog]

Now on to pump #2.
What I did here was repair two original check valve cages. (between the two pumps I had two cages in repairable condition) I started by using a Dremal tool to remove most of the pot metal or whatever was in there that wasn't part of the stamped cage. Then I soldered a #8 x 19/32 OD washer too the cage. (after installing the spring and seal) I had to make two new gaskets also for the check valves too seal against. (pump one didn't need any because of the o-rings) I filed down the solder on the inlet valve, so it would seal against the gasket. It pumps real nice by hand.

[Rudi]

Mark:

Excellent. I got a couple Kohlers as well... so this will eventually be helpful. I like to fix things instead of replacing them so if I can do that, that would be the first thing that I try. Keep us posted.

[indy61]

Today's fuel might not be compatible with some of the materials used in the old pumps.
I was thinking about buying a nos USA made fuel pump for my Kohler KT17 but was told it wouldn't last long.

http://www.ebay.com/itm/141944185181?_t ... EBIDX%3AIT

[danovercash]

I know this is different, but when I got tired of the wheel horse not using all of the tank capacity after the original pump warped and rebuild parts NLA. Went tot local commercial mower emporium an purchased a crank ase pressure driven pump for Kawasaki engine on x-mark mower. Problem solved! About $18.00

[Stanton]

I've gone through (2) Stens fuel pumps for my KT-17 since owning it. They want to leak gas into the crankcase or not pump enough fuel into the carb to keep up with demand.

Thanks for your thread. Informative!

[birddog]

I've had it up and running now and it runs at full throttle with no problem. I haven't had a load on it yet though, so I still can't say it's a 100% success.

The first time I started it I did have to put my finger over the outlet side to get it to start pumping. (the outlet check valve doesn't quite seal 100% - the spring and seal I used were both a little deformed) I put less then a gallon of gas in it and the hose from the tank was already on the pump. I'm thinking if I had let the gas start to flow through the hose before connecting it, it may have pumped rite away.