875/K181s original fuel pump question

[Ponyboy 64]

My 875 is bypassing the fuel pump, just working off gravity. I have the glass sediment bowl right below the gas tank and an in-line fuel filter  before the fuel line gets to the carb. I’m still working on getting it running, but I’ve noticed (and the PO mentioned this as well) that it doesn’t like the gas tank below half, as that’s the same level as the fuel inlet on the carb.

 

I’m wondering, would it be worth my time to connect to the pump? I’m still working on getting her running regularly (carb rebuild next on the list), but I’m curious to know if these things are easy to get up and running and reliable, or if I should consider an aftermarket option (would like to go longer than a half tank).

 

here’s some pics of the dormant pump.

 

 

[oliver2-44 9,748]

Any idea while the PO disconnect the fuel pump?

When the gas level in the tank is at the carb level you have no gravity to feed gas to the carb. 

Those metal pumps can be disassembled and gently cleaned. 

Rebuild kits are available from "Then and Now Automotive".. google their name.

Electric fuel pumps are also a simple option. 

 

 

[Ponyboy 64]

I never spoke to the PO, but my wife did. He told her of the gravity-fed issue and that it would work better if there were a pump, so I’m not sure if the pump doesn’t work and he knowingly bypassed it or if he didn’t know that was a pump and never tried it.

[Handy Don 12,217]

1 hour ago, Ponyboy said:

I never spoke to the PO, but my wife did. He told her of the gravity-fed issue and that it would work better if there were a pump, so I’m not sure if the pump doesn’t work and he knowingly bypassed it or if he didn’t know that was a pump and never tried it.

Likely bypassed without understanding the implications or options for repair.

Not long ago I rebuilt one of these with a jungle-sourced diaphragm and new gasket and it's doing fine. I did have to gently flatten the faces on the two halves of the pump body as there were a couple of high spots that would have led to leakage. Depending on age, the two one-way valves might be peened in or removable. They can be gently cleaned in place so I'd skip removing unless necessary. The "then and now" kit includes new valves, if you need them.

[Ponyboy 64]

Thanks, everyone! In the top pic, the out/right side has a brass fitting screwed in, with external threads on it and a much smaller-diameter hole on the inside that appears to reduce the volume of gas. The diagram provided in the Kohler manual is different than what I have, it shows two 90 degree barbed fittings coming out of the 'in' and 'out'. Do I need that 'flow reduction' fitting on the out-side only (with a barbed connector threaded onto that so I can connect my gas line)? I'm new to small engines and so trying to figure this all out.  

[stevasaurus 22,738]

There is a detent ball on each side of the pump.  If a horse has been sitting for a while, those balls can become sticky.  You also need the right gasket.  It is a pump gasket.  If the gasket is OK, some carb spray can loosen the detent balls.  Looking at the front of the engine...the ball on the left lets gas enter the pump.  The ball on the right stops the gas from draining back down from the carb.  
   Carb spray usually loosens these ball up, but you need a good gasket.  I think @buckrancher makes these gaskets.  If you take off the copper tubing from the pump and crank the engine.  You should see pulsing gas through the right end...it is working then.  

[Handy Don 12,217]

2 hours ago, stevasaurus said:

Looking at the front of the engine...the ball on the left lets gas enter the pump.  The ball on the right stops the gas from draining back down from the carb.  

Definitely this orientation on my K181 but I've seen the opposite on some engines, Steve, I guess because it made routing the fuel line easier when the carb fuel input is on the tractor's right side instead of left.  Since it wasn't connected when you got it, @Ponyboy, I'd say its a good idea to test if you're not sure.

 

A lot of K181's I've seen have a "U" of copper tube between the pump and the carb and use the "straight in" threaded connectors at the ends. Mine has barbed 90º nipples and plastic tube.

 

There is no need of a "flow restriction" and you can use whatever fittings make sense for your fuel routing. The pump moves very little fuel, really, and the carb's needle valve takes care of metering the fuel into the bowl at the low pressure that pump delivers.

[Handy Don 12,217]

@stevasaurus

FYI, example of the "other way" on a fuel pump from a post today