Pet cock leaks when opening it
 

On my 129, I generally keep the gas turned off since there seems to be an occasional leak somewhere at the carb. Today, when I opened the petcock prior to using the tractor, I noticed the shaft seems sort of loose and gas runs down from the top of the petcock. I tried tightening the nut directly above the shaft, but that didn't help. The obvious fix is to just replace the petcock, but thought I'd mention it anyway. Any suggestions other than replacement? Right now I have it open all the way and there is no leak from it - only when turning it. And, at this point, from messing with it, it leaks when all the way closed as well.

Petcock (referred to as "shut-off valve" on the parts website) appears to be part #951-3015 (replaces 751-3015). Looks like it's all one assembly. Price is listed as $21.52. I'll probably shop around and compare.

The packing material is wore out. I used a couple of small o-rings when I had that same problem.

Thanks. I'll just buy one. Hate, though, when a $16 item also has $10 shipping. Found one on eBay for $45🤪 I'll pass on that.

Search eBay for sediment bowl.

Thanks, but it appears those don't have a threaded piece that would screw into the bottom of the tank (?) :bigthink:

On ebay, using the advance search feature and the key words "cub cadet sediment bowl" gets you this

https://www.ebay.com/sch/i.html?_nkw...g=200&_fosrp=1

Jeff

Try to tighten the nut on the petcock, you have to open the valve to get it to tighten.

I tried to tighten this nut but it was bottomed out. To compress the packing under it, I loosened the nut and wrapped it with teflon tape. Then I was able to tighten the nut and stop the leak.

I bought one at my local lawnmower/small engine repair shop for about $11. You could also go with a little red, in-line shut off if you wanted to. Those usually sell for around $3 or so, but then you have to buy the clamps to secure the hose line to both ends of the in-line shut off. If your carb leaks, it sounds like it is time for a rebuild. If funds are available, the rebuild kit is usually $8-$12 for those and it will also help improve the performance of your cub.

Cub Cadet 123

I use this one .

Fuel Shut-Off Valve - Power Equipment Part Number : SME 702351
Fuel Shut-Off Valve - Power Equipment
Part #: SME 702351
Line: NAPA Small Engine Parts
Fuel Shut-Off Valve - Power Equipment
This item is not vehicle specific.
Online Price (USD):
$5.20
/Each

I bought a new shut-off valve and put it in. Are these things tapered? It screwed in fine, and then I checked to see if the amount of exposed threads is about the same as the old one, which it is. So added some gas, checked for leaks, etc. All good. Gradually added more gas, checked for leaks. Hooked up the gas line, checked for flow, filled the tank, THEN noticed that some gas is showing up at the top of the threads. Darn!!! I tightened the valve just a bit more but doing so not only didn't stop the leak but also turns the gas line over too far and so starts to interfere with the throttle. Would it have been better to go around another turn yet (which takes me back to whether it is tapered inside the tank)? It seemed tight enough and as though another full turn might have been a bit too much. The old one certainly backed off without seeming real tight. Possibly some dirt got caught in the threads after removing the old one? No longer a leak down through the stem but now I have the leak between the tank and valve. So.....what? Re-drain the tank and take out the valve again? Plumber's tape? I hate leaks of any kind. :angry: Weird how the leak didn't show up till nearly 20 minutes later. (Figures that it would wait to start till I had all the gas back in the tank!) Did it take the additional pressure of the full tank of gas to start forcing some through wherever it's getting past the threads?

did you use thread sealer? tape or paste is fine. if it needs to point a certain direction use tape so you'll get more turns without over tightening

Didn't use anything on it. Right now I've been turning it a bit tighter very gradually and then rechecking it. I can see where - even though it was lined up at about the same position as the old - I could actually turn it just by moving the gas line around - so obviously it really wasn't tight enough (probably could have been, as you say, with some tape on it - didn't think to do that cause there was nothing on the old (probably original?) one. The angle at this point is a bit off but - if the leak stops - I can always loosen and move the gas tank over just a bit and/or get a longer piece of gas line. It's really too short now as it is. When I first installed an in-line filter, I wound up cutting the one piece a bit too short. Right now I have the gas line passing on the inside of the throttle mechanism - might be able to move it to the outside. Trying to avoid re-draining the tank and taking the new valve back out if possible, but if that's what has to be done, no real problem.

For future reference, tapered threads always need a thread sealer of some sort. You may get it to stop leaking by more tightening but you will probably ruin the threads.

...meaning ruin them inside the tank...? I don't think I'll tighten any further. I'm about 45 degrees from the original position. It's barely leaking anymore - but still some gas evident on the one side of the valve. If it doesn't completely stop I'll have to take it back out. I have plumber's tape. Either way, I imagine retightening it (even if removing it again) will never go back to the original position so I have to get more fuel line.

The threads can be damaged on the tank and the petcock. If you wrap about 4 layers of teflon tape on the petcock you'll be able to rotate it to any position you like.

Still leaking. Going to have to take it back out. Wish I wouldn't have filled the tank. Next time I won't till I'm absolutely sure I can get this to work. Took apart the old one - all that's in there is a rubber o-ring. What is the 'worn packing' that I was told about as being the cause of the problem?

Been researching this and it seems that teflon tape is not suggested. Gas will eat through it eventually. Also, many people say they have never used anything when installing these and never had any problems. Loctite perhaps?

Correct. you need to use thread tape or dope that is meant for gasoline. When applying tape you want to apply enough that it starts to tighten pretty quickly in the threads. starting to thread in at different positions can help in ending up in correct position. It may take a time or 2 to get it tight and in correct rotation.

I use the yellow gas line thread tape for gasoline. It is double the density of the white PTFE. It holds up better to gasoline and other types of liquid and vapor gases.

Coop...I assume you're referring to this stuff..https://www.homedepot.com/p/Oatey-1-...kizec1dU17BzQ0

So you'd suggest that over some sort of loctite / permatex?

Don't take it personally, lots of crappy threaded parts come out of China. Poor attention to tolerances.

All the plumbers I've known always use both dope on the female threads AND tape on the male threads.

The O-ring is the packing material. Sometimes it is cork or string that wraps around the rod. The nut gets tightened just enough to compress the packing around the rod to prevent leaks. If the nut bottoms out (metal to metal) the packing must be replaced or increased. A few weeks ago I had that same problem and wrapped some teflon tape under the nut to get more compression. No more leak.

I would not suggest loctite or permatex on pipe threads.. Pipe dope or tape or combination of the 2. Pipe dope is not the same as peratex or loctite

Yes, the oatey yellow is fine

What my auto parts store had is some cheap yellow tape and so I bought permatex thread sealant. Guess I'll try that first, then if it doesn't work can always run over to Lowes and get the Oatey. I know they have it. The permatex is indicated as ok for fuel lines.

Permatex is a brand name. What product of permatex did you get. Usually when someone says permatex My mind assumes it RTV or silicone. Permatex does have hundreds of products so it does not surprise me if they make a pipe dope product

I used this one Says it is recommended for fuel systems. I took off the tank so as to be able to dry the threads; otherwise the gas just kept dripping down through the hole - figured it might not work to put sealant on threads already coated with gas. I noticed a small pinprick-sized hole right near the small plate that appears to be riveted to the fuel tank as part of the inside and outside fuel valve assy (?) It doesn't seem to go anywhere as far as I can tell and shining a light against it did not reveal any obvious light inside; though, again, no way to really know. I'm suspecting that tiny hole may have been there all along and I never had any leaks before now. I only noticed it wearing strong reading glasses. Guess I'll find out - time for a new tank if that's where the leak is from. I put a dab of sealant against it at any rate. I'll let the tank sit till tomorrow and probably won't add any gas till after the weekend. It says 72 hours for full cure. Only problem with the sealant as opposed to tape is that, once again, I had to tighten it nearly to the same degree and angle as what I tightened the old one to (in an unsuccessful attempt to stop the leak). It's off a direct line (from where it always was) by maybe 20 degrees or so. I'm buying some new fuel line anyway and if need be can make it longer. Problem is to avoid having the line interfere with the throttle mechanism.

Yeah.. thats not the product I would have chosen. Once that sets up it can be a real bear to get it apart again. If you find that the pinhole is leaking there are several different ways to repair it.

See what happens with it. Hoping I won't need to take it off again.

Having never used this particular product before, how long does it generally take to set up? Checked it this evening and at least the stuff on the threads below where it goes into the tank still appears to be nowhere near dry. Guess I'll have to wait the full 72 hours, as suggested, before doing much else.

An anaerobic sealant cures in the absence of oxygen. So, between the metal threads after the specified 72 hours, it should be cured and ready to hold pressure. The exterior exposed sealant will not cure. You may wish to wipe away the exposed sealant. I do not have direct experience with this particular product, but I expect it performs similar to Loctite anaerobic sealants.

I was thinking also that the stuff on the bottom threads might as well be wiped off if it's not going to set up due to exposure to air.

Coop...curious about repairing the pinhole. If need be, what would you suggest? Hopefully, as I said, it doesn't go all the way through the tank. Kind of wish now I would have gone with the Oatey tape, since, at least based on the visible portions of the threads, there appears to be no way to even know if this sealant is setting up.

There are several methods.. One would be to braise weld.. I would not suggest this unless you know the safety procedures in welding a gas tank. Another way is epoxy or patch made for gasoline tanks. JB weld makes a pretty good 2 part epoxy, There is also one called "seal all" that I have used.

Didn't think of JB Weld. I have some of that. Might as well put some on as a precaution. Easiest to do while the tank is off the tractor anyway. Thanks...

It has to be JB weld specifically for gas tanks.