Fuel pump question

[ekincaid]

So quick question,the 1250 I picked up as I mentioned had a blown motor...I got a sweet deal on a k301aqs engine out of a John Deere after some minor “engineering” its in and fits fine but that motor has a mechanical fuel pump on it should I remove the pump or can I run the engine with the gravity feed system with the pump drawing fuel from the tank in the proper location for the quiet lines.Im just concerned that the pump in action with the gravity feed might “overwhelm” the carb bowl,am I over thinking this??

 

[dschwandt]

Yup!!

 

[ekincaid]

Yup to the over thinking,or yup to my concern or both LOL

 

[kashaver]

The carburetors Kohler used in that time frame did not care if their fuel was delivered by pump or gravity. The supply pressure the pump develops is only about 4 psi. max. (Actually, the highest I have ever seen on a gauge was 2 psi.) On a 1250 with the tank above the carb. you can also bypass the pump and just let it seal the hole in the block, hook the fuel line directly from the tank to the carb. and it won't hurt anything.

There were some Briggs and some Honda carburetors that were fuel pump only. They had smaller inlet passages above the fuel needle in the seat so the pump pressure would not push the needle off the seat. It really can drive the mechanic nuts with a fuel-starvation issue if one of them is installed on a gravity feed system. As far as I know, these were made year 2000 and after.

 

[ekincaid]

So if I read this right if I wanted to plumb the pump to feed the carb on this engine I really wouldn’t be a problem

 

[danderson]

Plumb it tank to carb

 

[kashaver]

Yes.

You can run from tank to fuel pump to carburetor. Or (if the tank is above the carburetor) You can run from the tank directly to the carburetor.

On that engine either way will work.

 

[ekincaid]

Got my 1250 running today and it runs great with the mechanical fuel pump in place thanks fellas

 

[buck]

if for any reason, on any mechanical pump system, if you bypass the pump, you will want to put some fuel in the hose discharge from the pump and plumb it back to the suction side of the pump, , you want some fluid going thru the pump, this is because you do not want a pump diaphragm running dry air thru the pump, it will damage and eventually fail the dry diaghram, they need to be wetted, buck