My T has a Holley NH that I find has to be really lean for best results. REALLY lean, like with the needle turned all the way down, which I would have thought should cut off fuel flow entirely. I rebuilt the carb myself a couple years ago and it included a brand new needle and all new gaskets. I made sure to hone the point of the new needle as smooth as I could get it too.
So at this point I assume the spray nozzle could use a closer look, does that sound about right?
That would be a place to start. Let us know what you find
Needle too short / Wrong needle / Needle threads bottoming before needle bottoms in nozzle. Spray Nozzle loose in carb body. No spray nozzle gasket. Badly scored needle. Float too high.
Most other tasks are complete on the car so my plan of attack for this weekend (hopefully) is to pull the spray needle to see if the tip is all screwed up, then drop the bowl off the carb and check on the spray nozzle itself. Hopefully it's an easy fix.
Tim -- I wish you luck because the easy fixes are the hard ones.
I went to replace the front brake pads on my Chevy Silverado because they were getting thin.
The easy fix took me two days, 4 rotors, 4 calipers, 4 brake hoses, 2 big containers of brake fluid, a part of a brake line, and I had to replace an impact socket.
Other than that it was an EASY fix!
Fred it's funny how every ten minute job can so easily become a three week ordeal, isn't it?
You might roll the needle on a flat surface to see if it is bent. Just a tiny amount of deviation can result in the tip not staying centered in the spray nozzle as you adjust the richness.
The spray nozzle threads in from the bottom. It is right in the center where the screw holds on the bowl. If it was not tightened down snug or if the gasket was left out, your needle could be loosening it when you screw all the way down. This happened to me on a tour and one of the other members found the problem and fixed it for me. If this is your problem, you can turn off the fuel at the tank and then remove the bowl, tighten up the spray nozzle and re-install the bowl and your problem is solved.
Thanks Norm, thatís the plan for as soon as I get my jungle of a lawn mowed.
The spray nozzle seemed to be in tight, though the rest of the carb was pretty gross inside. Was it the spray nozzle gasket that was best replaced with a lead one?
From the looks of the bowl, I would suspect that some of that rust has gotten into the inner passages of the carburetor. Time for a rebuild and look for another better bowl. Used NH carburetors are pretty common at swap meets. There are even some rebuilt ones there. It is not hard to rebuild one, but you do need some good parts to begin with. You could try bead blasting that bowl and if the gasket surface at the bottom is still good and it is not rusted through you could possibly use it.
The bowl and carb are really in better shape than the pic lets on. I suspect most of what was in that bowl was trash that made it down from the tank before I had it properly cleaned. Itís all cleaned and put back together now, and runs.
Just a little more follow up: I pulled the bowl and spray nozzle off and gave everything a good cleaning. The nozzle seemed to be in tight and with no issues other than a small burr at the edge of the hole. I cleaned the burr off, reassembled with a little bit of sealant this time in case it was the gasket, then reinstalled. Tried the engine and the problem persisted.
Thinking the needle friction nut did some other job, I snugged it down some and found after that I could now lean the engine enough to kill it. That shouldnít have fixed it as far as I can tell, but the carb does seem to work properly again for now. It seems the best setting is around 3/4 turn open.
The lead gasket would be for the float valve. The ones sold in the kits are too hard, some seal some don't. Thanks for the update.