12 replies to this topic

[leeave96]

I've been working with one of my mighty fine 520H tractors trying to get it running and as with my other Wheelhorse tractors, after they have set for a long time it seems like it's a chore to get gas up from the rear tank to the engine carb. Once the engine fires, no problem, the fuel pump takes over. So I find myself either giving the tractors a shot of ether or sucking fuel up the fuel line by mouth to prime the upper end of the fuel line and filter. I don't like doing either.

What I'm thinking about doing is putting an inline fuel primer bulb on and giving that a try - not unlike one used on a boat.

What do you think?

Thanks!
Bill

[can whlvr]

i asked this question a while back too,so it will be interesting if any one has done it,if no one does i might put one on and try it

[TT-(Moderator)]

Close the fuel valve as soon as you park the tractor - but remember to open it before you use it the next time.

To make that task even easier, install a 1/4 turn B&S 493960 (or equivalent) shut-off in the line somewhere close to the fuel pump.

[CRE1992]

Are you looking for a primer for a K series or Magnum kohlers? If so I know where you can find them, of course you have to modify your carb a little though. Nothing too challenging.

[leeave96]

CRE1992, on 28 January 2012 - 01:46 AM, said:

Are you looking for a primer for a K series or Magnum kohlers? If so I know where you can find them, of course you have to modify your carb a little though. Nothing too challenging.

The Kohler I have is a Magmun the rest are Onan.

Thanks,
Bill

[amcrules00]

Normally after use, I shut off the fuel valve and let the engine run out of fuel.
I wonder if there are particulates in the bottom of your tank obstructing the flow of fuel to the carb, making the pump work harder? Could be old fuel line collapsing on start up too, might need replacing?

[TT-(Moderator)]

This happens because a weak or leaky "check valve" or diaphragm in the pump allows the gas to run back to the tank and the pump loses prime. As the pump gets older, it takes longer to pick the fuel up again. If the shut-off is closed, the gas can't drain back.
Lightly pressurizing the tank is the easiest way I have found to prime the system. I use the air compressor - if it's not empty (air nozzle wrapped with a rag and inserted in the filler opening) or I just use my lungs.

Perhaps an inline check valve installed immediately after the shut-off valve would be a solution.

[CRE1992]

Here, about 3/4 of the way down the page.... http://gardentractor....com/a1carb.htm

[leeave96]

Update: I got the 520H going. The problem was the entrance to the carb was clogged - most likely by varnish. I disconnected the fuel line from the fuel filter at the top of the engine and filled it with carb cleaner and let a collumn of that stuff set there for a week. Today, I gave it a little puff of air with my mouth (bleeekk!!!) and it cleared. I then primed the carb from the same fuel line, hooked everything up and after a couple of cranks, the tractor fired up.

I bought a primer bulb, NAPA P/N 188002EPN and it was about $25. If you can find the older version which is non-EPA, it is about $10. The only difference in part numbers is the older version does not have the "EPN" at the end. I haven't installed the bulb yet. I blew through it and found a bit of resistance. Not sure the fuel pump can overcome this. If I do install, it will be at the rear of the tractor, pointing down such that gravity can fill it and not tax the fuel pump when running.

Thanks!
The other Bill

[amcrules00]

Good to hear you got it sorted out.

[Rollerman-(Super Mod)]

I've had a few hard starting Onans on account of crud in the tank blocking the outlet, crud in the fuel pump holding the reed like valves open inside or crud in the carb.
All can be cleaned with a little time and effort.
Take a little time sorting through everything & save the primer bulb for the boat.

[can whlvr]

on my tractors that do this are very clean,i think tt is correct as my 1975 16hp takes alot of cranking,definatly weaker fuel pump as it looks to be orig,and it propally has a weak check valve,because when shes warm or been working recently it fires up much quicker,i guess the fuel hasnt drained back,thats why i thought of a primer too like bill thought,im goint to try the shutoff,i have an old fuel cap,might have to build a cap tyhat i can put a little in inwith the compressor,just i little though,dont want to blow up the tank

[specialwheelhorse]

After talking with an old wheel horse dealer I know, he told me he never left a horse
leave the shop without installing one of those quarter turn fuel shutoffs in line
also helps occasional gas in sump problems on older tractors.
JIM