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We successfully rebuilt both of our 1971 710M Zenith 36NDIX carburetors.

But we noticed a seep from a metal plug in the top cover when we ran the engine after the rebuild. There are no other leaks.

We had heated both carburetors to 250F for one hour in the oven in order to get the bottom base screws out. We dipped one carb in carburetor cleaner overnight, and the other one for a few hours.

What should we seal this metal plug leak with? JB Weld? Silicone sealant? Gasket sealant? We're taking a 2 week trip in the Pinz in a couple of weeks and need to seal these seeps.

It appears we might also be losing the fuel from the bowl. The few times we started it during the first runs after the rebuild it seemed like we had to pump a lot of fuel in it to get it to run. Is there a weld plug that would allow fuel to drain from the float bowl?

bbolander

The only plugs I am aware at the bottom of the main body are the two valves fo the accelerator pump and thestarter jet.
to the left of the choker assembly is a small M4 screw .

if the metal plug in the top part is leaking through the metal plug i would blame it on the heat you applied.
drill it outhe plug, cut a thread and close the hole with a screw

Hotzenplotz wrote:bbolander

The only plugs I am aware at the bottom of the main body are the two valves fo the accelerator pump and thestarter jet.
to the left of the choker assembly is a small M4 screw .

if the metal plug in the top part is leaking through the metal plug i would blame it on the heat you applied.
drill it outhe plug, cut a thread and close the hole with a screw

We don't know for sure whether it was leaking before the rebuild and heat, but I think like you the heating might have done it. Good solution, but probably won't be able to do that before we take our trip. So still looking for a way to seal the plug even if temporary.

Oops, not thinking correctly. When we heated the carbs in the oven the top cover plate was not on the carbs. It and the internals had been removed. So it couldn't have been the heat applied.

Still looking for a sealing solution.

Is there a missing copper washer here or one that needs to be annealed?
Can't be an NPT fitting then y'd need fuel safe thread sealer.

Loctite 290 (wicking grade, high strength, green) is supposed to seal porosities in metal welds, etc. As the PSI is not more than about 4PSI, it should seal easily and the Loctite specs say it is "chemical resistant, seals oil reservoirs, transmissions" (not a direct quote) so I would expect it to work well for gasoline at this low pressure. Drain out the fuel in that section, apply the wicking Loctite to the seam, and let cure for a day. I suspect it will solve your problem and is quick and easy to try.

Jimm391730 wrote:Loctite 290 (wicking grade, high strength, green) is supposed to seal porosities in metal welds, etc. As the PSI is not more than about 4PSI, it should seal easily and the Loctite specs say it is "chemical resistant, seals oil reservoirs, transmissions" (not a direct quote) so I would expect it to work well for gasoline at this low pressure. Drain out the fuel in that section, apply the wicking Loctite to the seam, and let cure for a day. I suspect it will solve your problem and is quick and easy to try.

Thanks Jimm, we'll give that a try.