fuel pump questions

Mini Bike & Go-Kart Parts

#2
I guess I will find out myself, so far it wont pump fuel over 9'' high the way it sits. I'm under the impression these pumps do better at pulling rather than pushing, and that's why most are mounted on the engine or close to the carb. This is a bit off topic, but I'm working on an old 1979 Wheel Horse lawn tractor with a 12 HP Kohler cast iron engine. The original fuel pump was mechanical and took a dump. A replacement is about $150.00. I robbed a pulse pump from a 11 hp Kuboto vertical shaft mower, and pulsed it from the dipstick tube on the Kohler. The pump is mounted on the firewall, which is about halfway between the tank and the carb. The gas tank is in the rear, and the bottom of the petcock is 13" below the fuel inlet on the carb. There is about 30" of fuel line on both sides of the pump.
Once I get it primed to the carb it will fire right up. The problem is when under a load, the fuel pressure isn't sufficient enough. It's like it has enough pressure to keep a siphon going until the fuel rate exceeds it.
I'm going to try mounting the pump closer to the carb. Presently it is trying to push fuel over 30" of line and up 13".
 
#3
I guess I will find out myself, so far it wont pump fuel over 9'' high the way it sits. I'm under the impression these pumps do better at pulling rather than pushing, and that's why most are mounted on the engine or close to the carb. This is a bit off topic, but I'm working on an old 1979 Wheel Horse lawn tractor with a 12 HP Kohler cast iron engine. The original fuel pump was mechanical and took a dump. A replacement is about $150.00. I robbed a pulse pump from a 11 hp Kuboto vertical shaft mower, and pulsed it from the dipstick tube on the Kohler. The pump is mounted on the firewall, which is about halfway between the tank and the carb. The gas tank is in the rear, and the bottom of the petcock is 13" below the fuel inlet on the carb. There is about 30" of fuel line on both sides of the pump.
Once I get it primed to the carb it will fire right up. The problem is when under a load, the fuel pressure isn't sufficient enough. It's like it has enough pressure to keep a siphon going until the fuel rate exceeds it.
I'm going to try mounting the pump closer to the carb. Presently it is trying to push fuel over 30" of line and up 13".
Pap I think you would get a better pulse from the intake. Especially under load. I have a Club Car Carryall that is gas and the pump on it is mounted on the back of the seat. It is about 15 inches above the bottom of the fuel tank with about 24 inches from the pick up to the pump and about 30 inches from the pump to the carb which is about at the middle of the tank height wise. It is just a small square pump like any other, nothing special. But maybe it will give you a reference. Mine works good but I wouldn't call it great. If it sits all winter you do have to pressurize the tank to prime the system, which I would say is typical but if you use it regularly it is always ready...

Doug
 
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#4
This is probably the same pump you have, it's about 2" square. It was mounted and pulsed from the crankcase of the Kuboto, with about 4" of of pulse line. I can't really pulse it from the intake as it has no manifold, the carb bolts directly to the block.
When I tested it before I mounted it, it seemed to pump real good into a can, with the can being held about 8" below the fuel inlet. Right now I have a filter about 4" below the fuel inlet, and it gets there pretty quick, but the last 4" it really struggles. Do you think maybe I should put the filter before the pump?
 

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