redruff

Member
arrghhh.

'58 641....
same dang problem!


new shutoff valve, new gas line, line rubber gasket on sediment bowl, rebuilt carb.

last week I shut the gas off and ran the tractor until it died. let it sit for a week, still!! about a 1/8 of a cup of gas ran out of the carb when I took the air hose off!

How is it getting in there! was it just what was left in the has line or something! Fuel poltergeist?
 
"I shut the gas off..." Likely just though that you did. Some valves are not any good. Remove line or sediment bowl, put cup under it, valve off & check cup for gas after an hour.
 
(reply to post at 22:14:14 09/22/13)
well I'm leaning towards that! its a pretty simple gravity feed system! if there is gas getting tohe carb, its gotta be going through t he valve.
 
When you get tired of beating your head against the
tire, go to Red Rock and consider the electronic
shutoff valve. I put one in about 5 years ago and it
works great for me.
 
Probably a crappy sed. bowl unit. I put a SS ball valve between the bowl and the carb on my 60, works as it should.
 
Should have mentioned that I had just changed the oil and filter a week before discovering the crankcase 1/2 full of gas and the gas tank empty--what a waste ! P.S. I don't care what it looks like or if original--it's freakin' bullet (leak) proof. HTH
 
There are actually two shutoffs here, the one on the tank
and the needle valve and seat in the carb.
Neither one appears to be working or the leak would stop.
I've put two new tank valves on my 960 and they both leaked.
Cheap (not inexpensive) junk.
The one I took off first was not original either.
I finally got one of them to mostly seal and with a working
needle/seat it no longer leaks into the throat.
 
between the quality of todays new parts :(
and the
'OMG, which genius engineer thought up THIS design'
on 60x-80x tractors, :shock:
I also add a hardware store ball valve to the line
as close as I can get it to the tank valve.
If the tank valve doesn't leak externally, I leave it on
as touching it will guarantee a leak sooner or later,
and just use the ball valve to shut off fuel.

on tractors with a tank sediment bowl, I leave it in place as it has a needed function.
I just add a shutoff to the bowls exit threads, or to the line very close to it.
 
Try putting a new o ring in the original valve next time.Open the valve just two turns.I can plow and bale hay on 2 turns open.Opening more turns wears the O ring.The original valves were made by Bendix and a new O ring will fix them.Electric valves are not a cure all.If a bit of dirt gets caught in them they will leak.Model A Ford taught me to shut the gas off when I parked it.
 
Those tractors have the worst gas valve ever made.

I use an in line needle valve like used on an ice maker supply line. Better than those cheap ball valves sold for lawn mowers etc. Some of those work and some don't.

Zane
 


new shut off valve, o ring, new gas line, new sediment bowl screen and rubber gasket. rebuilt carb with new seat and needle, the rubber tipped one. tapped it a couple times to seat it. checked float for leaks, checked for proper clearance of float.

that's why I'm beating my head against the tire! lol...

but as I said....if there's gas in there after shuting off the valve, no if ands or butts...the valve has to be leaking....no way around it!

one thing I've never mentioned, the gas always has a little brown tinge, which I attribute to just eating away at the air cleaner hose, and the carberator always looks "sweaty" which I just think is gas saturing the gasket?
 
I would check the float valve seat. They are really hard to get leak free. Took me three tries on my 660.

This is what I did. Took the top off the carb, removed the float and needle, and left the mounting studs on. Placed it upside done in a bench vise with the studs clamped lightly. I then ground an old wood chisel to tightly fit the float seat. I put an adjustable wrench on the chisel and tightened. I got about 3/8 of turn on that puppy. I thought I had it tight before. Good news was no more leaks.

All I can say is that is what worked for me.

BTW, I agree, those hundred series shut off valves are the pits.
 
It seems to me that what you have in your gas line is similar to a drinking straw and a milkshake. If you hold a finger over the top of the straw nothing comes out the bottom, at least for a while. This is cause the top is not vented. Take your finger off the top of the straw and it drains.

The amount of time the engine runs on gas left in the carb is not long enough for the burps that have to happen to drain that line.
 
Try your shut down sequence as before, except crack open the top of the gas line as soon as you shut off the gas. The gas should drain down quickly and keep the engine running till burned off.
 

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