Fuel pumps mounted vertically or horizontally?

Overly Cleaning Service

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I have a 20hp kohler command powered custom made truck mount. If it runs for a while and then gets shut off it doesn't like to start back up until it cools down.. Im guessing this is due to a vapor lock issue.
The fuel pump was mounted horizontally on the truck mount frame when I purchased it. I thought i had read that if you didnt have your fuel pump mounted vertically then you would run in to vapor lock issues. So, i mounted it vertically and am having vapor lock issues. I have never run the unit for an extended amount of time with the fuel pump horizontally so i cant say how the vapor lock reacts to that mounting position.
Does it matter if the fuel pump is mounted vertically or horizontally? Maybe the pump is getting too hot and i need to keep it cooler?
 

wuznmee

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Guessing can get expensive. Hook up a fuel pressure gauge to it and actually verify the pressure. You can get a cheap fuel pressure gauge at any auto parts store.
Most TM's with lawn mower engines do mount vertically, with the inlet at the top.
If you do need to install a new pump, read the directions for how the manufacturer wants it mounted. And... I agree with Kevin, get it out of the van, it's dangerous in there.
 

Overly Cleaning Service

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I have pulled the gas line off the motor and activated the fuel pump to make sure its getting fuel when it did not start. The fuel pump was pushing gas out not sure of the fuel pressure though.
The fuel pump is mounted vertically with the inlet sucking the gas out of the tank and the out to the motor is on the top. Is that the proper way?
I could try and mount the pump horizontally like it was originally and see how it likes that as an experiment.
 
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Overly Cleaning Service

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Fuel pump directions say to mount it vertically with the outlet above the inlet. Mounting horizontally does not effect the pumps performance so the directions say.
Maybe the pump is getting too hot if its mounted correctly. I read some post on the forum saying the heat will cause the pump to vapor lock.
I also need a in line fuel filter. It currently is without filter. Any suggestions on a fuel filter? I tried a plastic Fram filter from walmart and the pump didnt want to push gas through it.
 

wandwizard

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I have serious doubts that your fuel pump is the problem, but it could be especially if it's the wrong kind. It would be worth your while to get one of those pressure gauges to see if it's giving you the correct pressure. B & S engines I think can have no more than 3 psi. I don't know what it is on Kohler, but doubt it's any more than that. My pump states it puts out 2 to 3 psi. I use a simple metal fuel filter you can get anywhere placed before the fuel pump coming from my gas tank. I don't even bother with those little plastic filters. I would mount the thing under your van. Just safer all the way around. You can get a simple fuel pressure gauge that can be permanently mounted inline if you like.

Here is my fuel pump and filter although I usually just buy my filter at Auto Zone. http://https://shop.truckmountforums.com/fuel-pump.html
http://https://shop.truckmountforums.com/ea-filter1-4fuel.html
They also sell this filter for Kohler that states it should be placed inside near the engine.
http://https://shop.truckmountforums.com/fuel-filter-kohler.html
I honestly don't know if it makes a difference, but doubt it. I've gotten by just fine with the metal filter.

On a side note there could be something else causing the machine to shut down. Really depends on the machine. You said it was custom made so you may need to contact the manufacturer. Did it even come with a manual with a trouble shooting guide? Very well could be something else causing your problem. On my machine something as simple as a clogged orifice causes the exact same problem. An oil pressure sensor could possibly cause it too. Just throwing out some ideas. I'm not a mechanic, but have to fend more myself most of the time when I have a problem with my machine so take this for what it's worth. Just trying to help.
 
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wuznmee

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I have pulled the gas line off the motor and activated the fuel pump to make sure its getting fuel when it did not start. The fuel pump was pushing gas out not sure of the fuel pressure though.
The fuel pump is mounted vertically with the inlet sucking the gas out of the tank and the out to the motor is on the top. Is that the proper way?
I could try and mount the pump horizontally like it was originally and see how it likes that as an experiment.
Fuel flow and fuel pressure are two different things. A bad pump may flow freely... until you put it under pressure and, turn the pump over so the discharge side is down.
 

Overly Cleaning Service

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Have you checked for spark when it shut down?
You may have a coil going bad.
The motor never actually shuts off by itself. For example..I shut it off after cleaning for a hour on a job because i had to move my trailer for the moving truck. When i got back in to position it didn't want to start back up. Eventually it did start after i checked the spark, fuel, and the waste tank full switch to make sure all were working. Then ran fine for the rest of the job.

I have serious doubts that your fuel pump is the problem, but it could be especially if it's the wrong kind. It would be worth your while to get one of those pressure gauges to see if it's giving you the correct pressure. B & S engines I think can have no more than 3 psi. I don't know what it is on Kohler, but doubt it's any more than that. My pump states it puts out 2 to 3 psi. I use a simple metal fuel filter you can get anywhere placed before the fuel pump coming from my gas tank. I don't even bother with those little plastic filters. I would mount the thing under your van. Just safer all the way around. You can get a simple fuel pressure gauge that can be permanently mounted inline if you like.

Here is my fuel pump and filter although I usually just buy my filter at Auto Zone. http://https://shop.truckmountforums.com/fuel-pump.html
http://https://shop.truckmountforums.com/ea-filter1-4fuel.html
They also sell this filter for Kohler that states it should be placed inside near the engine.
http://https://shop.truckmountforums.com/fuel-filter-kohler.html
I honestly don't know if it makes a difference, but doubt it. I've gotten by just fine with the metal filter.

On a side note there could be something else causing the machine to shut down. Really depends on the machine. You said it was custom made so you may need to contact the manufacturer. Did it even come with a manual with a trouble shooting guide? Very well could be something else causing your problem. On my machine something as simple as a clogged orifice causes the exact same problem. An oil pressure sensor could possibly cause it too. Just throwing out some ideas. I'm not a mechanic, but have to fend more myself most of the time when I have a problem with my machine so take this for what it's worth. Just trying to help.

Thanks for the filter advice! I purchased the unit a few owners down. It has no owners manuals or markings to determine original manufacturer. It looks like someone built it themselves.
 

Kevin Dumas

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The motor never actually shuts off by itself. For example..I shut it off after cleaning for a hour on a job because i had to move my trailer for the moving truck. When i got back in to position it didn't want to start back up. Eventually it did start after i checked the spark, fuel, and the waste tank full switch to make sure all were working. Then ran fine for the rest of the job.

I have heard quite a few people have had restart problems with Kohler engines after they shut them down when hot.
My 38hp does it till I open the throttle wide open and sometimes have to hit the choke a bit.
 

Todd the Cleaner

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I have heard quite a few people have had restart problems with Kohler engines after they shut them down when hot.
My 38hp does it till I open the throttle wide open and sometimes have to hit the choke a bit.
My 40 horse Kohler is a PITA to start if the engine is hot. It will fire right up first thing in the morning and will start just fine if it cools off for a half hour between jobs but if I shut it off and try to restart it the carb will flood out every time.