Vacuum pulse system questions

[ebinmaine 67,397]

3 things....

 

I have a Mikuni vacuum pulse fuel pump that's off of a Briggs 11 HP engine. 

 

I'd like to use it for the OHV160 on the Tecumsehorse C160-8. 

 

The bottom of the fuel tank is above the carb at level ground. I won't need a super strong pump. Just enough to feed on uphills if at all.  

 

What I'm wondering is,

1. How long can the Vacuum line be? Or, should I make some of it out of metal?

 

2. Is there an issue with running the fuel line  -  metal or rubber  -  under the engine?

 

3. If using a metal fuel line how close to the muffler can it be?

 

[953 nut 55,163]

2 minutes ago, ebinmaine said:

1. How long can the Vacuum line be? Or, should I make some of it out of metal?   Rubber fuel hose should be fine. Keep it under 100 feet and you'll be OK   

 

2. Is there an issue with running the fuel line  -  metal or rubber  -  under the engine? If you run a metal line be sure to put a loop in the engine end of the line to absorb vibration.

 

3. If using a metal fuel line how close to the muffler can it be?  I would run it on the other side under the flywheel cover.   

 

[Ed Kennell 38,114]

19 minutes ago, ebinmaine said:

how close to the muffler can it be?

 My Honda powered P-UP died on a hard pull.    I had the exhaust pipe too close to the fuel line causing vapor lock. 

[ebinmaine 67,397]

24 minutes ago, Ed Kennell said:

 My Honda powered P-UP died on a hard pull.    I had the exhaust pipe too close to the fuel line causing vapor lock. 

 

That's my concern. Likely I'll play it safe and keep them well separated but I'm curious what the safe distance is.  

[Pullstart 62,831]

Remember that gravity is the same, whether there is a drop or not.  You still have to pull the fuel up the difference between the tank and the carb.

[ebinmaine 67,397]

6 hours ago, Pullstart said:

Remember that gravity is the same, whether there is a drop or not.  You still have to pull the fuel up the difference between the tank and the carb.

 

Yessir. UP is the only reason I even need a fuel pump on this. 

 

 

 

[ebinmaine 67,397]

@953 nut 

 To elaborate on my questions and your answers...

The reason this comes to mind is that the fuel pump inlet and pulse feed point the wrong way for this application. 

I'm trying to figure out if I should put a sharp bend in the flow tube or run the main feed a different direction.  🤔 

 

I'd much rather follow the flywheel cover but that'll require a 180⁰  turn somewhere in the feed.  

 

 

[953 nut 55,163]

          I see no reason that the fuel pump couldn't be mounted remotely from the engine as long as it is below the tank outlet providing net-positive suction head.

NPSH (Net Positive Suction Head) is a measure of the pressure experienced by a fluid on the suction side of a pump. 

[Wild Bill 633 845]

@ebinmaineBe sure to add a fuel shut with a pulse pump. If the diaphragm fails gas can run from the inlet to pulse line into the crankcase.

[ebinmaine 67,397]

5 hours ago, Wild Bill 633 said:

@ebinmaineBe sure to add a fuel shut with a pulse pump. If the diaphragm fails gas can run from the inlet to pulse line into the crankcase.

 

Appreciate that Bill. Where exactly what I put the shut off? I have them on every tractor at the bottom of the tank but to be honest, never use them. I can change habits because Red Green said so.

[Bill D 1,916]

What did you decide to do?  Pictures?  I'm a big fan vacuum pulse pumps.

[ebinmaine 67,397]

7 hours ago, Bill D said:

What did you decide to do?  Pictures?  I'm a big fan vacuum pulse pumps.

 

For this particular application I decided to keep using the Facet electric fuel pump that was already in there... for now.  

The main reason is not wanting to run fuel and vacuum lines in sharp bends or odd places until I get more familiar with this engine, and the tractor's purpose. 

 

I still have 2 of the above mentioned pulse pumps on the shelf for future usage.