lp gas leaks
- Thread starter grapegro
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Norm,
If you have gas leaking out the vent hole in the top cover, you have a hole in the diaphragm. Replace it. If gas is leaking at the outlet port of the regulator, the needle valve/seat is the problem area. If it is in this location, use a depth mic to check the bored .355" dia. hole depth. It should be .360" deep with a nice flat bottom for the gasket to seal the brass seat assembly. Overall depth of the 7/32" dia hole should be .800". This determines spring tension on the needle. The cavity below the diaphragm should be .140" deep which allows the diaphragm to just rest on the needle pin projection. Verify all depth dimension. They should be very close to what Jerry specified for the regulator to work and seal properly.
Jeff
If you have gas leaking out the vent hole in the top cover, you have a hole in the diaphragm. Replace it. If gas is leaking at the outlet port of the regulator, the needle valve/seat is the problem area. If it is in this location, use a depth mic to check the bored .355" dia. hole depth. It should be .360" deep with a nice flat bottom for the gasket to seal the brass seat assembly. Overall depth of the 7/32" dia hole should be .800". This determines spring tension on the needle. The cavity below the diaphragm should be .140" deep which allows the diaphragm to just rest on the needle pin projection. Verify all depth dimension. They should be very close to what Jerry specified for the regulator to work and seal properly.
Jeff
Hello Jeff,
Checked all those measurements and all seem to be okay. The leak I experience is when the diaphram and cover is off, gas does show leakage around the needle and not around the valve body. I test this leak with detergent water and bubbles show easily. I am trying to use this on my hit and miss Rosebery engine and the leakage is flooding the engine while the engine is "missing" Norm
Checked all those measurements and all seem to be okay. The leak I experience is when the diaphram and cover is off, gas does show leakage around the needle and not around the valve body. I test this leak with detergent water and bubbles show easily. I am trying to use this on my hit and miss Rosebery engine and the leakage is flooding the engine while the engine is "missing" Norm
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Norm,
If the spring is holding the needle against the seat, the seat has to be the problem. I would replace the entire rubber seat assembly.
Jeff
If the spring is holding the needle against the seat, the seat has to be the problem. I would replace the entire rubber seat assembly.
Jeff
Hello Jeff,
This was happening to the first valve assy I had with no use. It is happening to the one I just received as a replacement. Could it be the way the soft seat for the valve is put in, could I be fitting this wrongly? It does seem funny that this is happening to two different valves.I cannot find a source for these Tecumseh parts in Australia, and they become quite costly to get them from the States, so replacing one does present a problem especially if this leak problem is not going to be fixed.
Norm
This was happening to the first valve assy I had with no use. It is happening to the one I just received as a replacement. Could it be the way the soft seat for the valve is put in, could I be fitting this wrongly? It does seem funny that this is happening to two different valves.I cannot find a source for these Tecumseh parts in Australia, and they become quite costly to get them from the States, so replacing one does present a problem especially if this leak problem is not going to be fixed.
Norm
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Norm,
You have narrowed it to the needle assembly. You need to very closely inspect the needle seat and the soft seat for imperfections or damage, then try reversing the soft seat (although it should seat either way). Lastly, make sure the needle spring tension is adequate enough to keep the needle against the seat without the assistance of inlet gas pressure.
I think we have covered all the possibilities. The fix is somewhere in there, you just have to find it. If you don't have any success, send some close up photos.
Jeff
You have narrowed it to the needle assembly. You need to very closely inspect the needle seat and the soft seat for imperfections or damage, then try reversing the soft seat (although it should seat either way). Lastly, make sure the needle spring tension is adequate enough to keep the needle against the seat without the assistance of inlet gas pressure.
I think we have covered all the possibilities. The fix is somewhere in there, you just have to find it. If you don't have any success, send some close up photos.
Jeff
Hello Jeff,
There are no instructions on how the soft seat is fitted into the valve body. You say I should replace the entire rubber seat assy, do you mean the brass valve body too or can the soft seat be purchased on its own?
There are no instructions on how the soft seat is fitted into the valve body. You say I should replace the entire rubber seat assy, do you mean the brass valve body too or can the soft seat be purchased on its own?
canadianhorsepower
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there is a ring or circle on the seat it goes in the bottom
look at the picture
this is the link to get the seat
http://www.ebay.co.uk/itm/TECUMSEH-CARBURETOR-FLOAT-NEEDELVALVE-NEEDLE-SEAT-KIT-632709-/141591710601
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Norm,
Work with the seals you currently have first provided they are not damaged. Gently blow out the soft seal from the brass housing using pressure air. Reverse it and seat it as shown in Canadianhorsepower's illustration. You did not say if your spring is holding the needle against the soft seal. Modest spring tension is needed. A couple photos below might help. The first is the needle seat parts and the second photo showing the assembled demand regulator with the diaphragm removed. Note projection of needle pin above the brass hex. When pressed down, the pin should pop up under spring pressure. Hope this helps.
Jeff
Work with the seals you currently have first provided they are not damaged. Gently blow out the soft seal from the brass housing using pressure air. Reverse it and seat it as shown in Canadianhorsepower's illustration. You did not say if your spring is holding the needle against the soft seal. Modest spring tension is needed. A couple photos below might help. The first is the needle seat parts and the second photo showing the assembled demand regulator with the diaphragm removed. Note projection of needle pin above the brass hex. When pressed down, the pin should pop up under spring pressure. Hope this helps.
Jeff
