Another who would thunk it

I am disappointed with the NAPA carburetor kit I got for the 961.

I posted a few days ago about issue with needle and seat leaking, put the old ones back in tonight, and works fine.

The kit came with new idle jet screw, well it still ran too rich with idle screw all the way in, I found the old one, and check the lengths. The taper on the new one was shorter than the original, it would bottom on the threads before seating all the way. The original will kill the
engine when screwed all the way in, like it should. I had always assumed that if the tractor did not kill when the screw was all the way in, there was a problem elsewhere, but it can be the wrong geometry on the screw causing this.

As stated, who would have thunk it?

Neighbor has a similar issue with the main jet screw. His carb kit came with a washer he put under the spring on main jet. This prevented the main jet to come in contact with the bottom to kill the engine. Spark plugs would turn black with carbon in minutes, running too rich.

All I had to do is remove the extra washer so we could properly adjust main jet to lean it out the fuel mix.

Sometimes, not saying it's your case, the carb has been changed
and you get the right kit for the "tractor", but not for the current carb.
I always order for the carb model number, not the tractor.
Then you still might have to deal with the land of almost right.

I gave them tag number

In this day and time: it appears to me that some of the parts companys do that "one size fits all " deal. Selling the same kit (or parts) for a variety of applications even though there might be a difference in original parts. Bought a rebuild kit for a Moline "G " (carburetor) . It would run out of fuel under load. Discovered hole in needle value seat was about half the size of original. Running carburetor dry under load.

I've noticed differences in carb kit parts before. Nothing new or specific to any brand kit.

I'm sure the carb kit "assemblers" often put together a hodge-podge of available parts that look "pretty close" to what's supposed to be in there, especially with the slow moving, near obsolete {which covers about all carbs now) models. Not economically feasible for them to have to special order the right screws for something that may sit om the shelf for years. They also like to combine models, put together one kit fits several different carbs.

What do they have to loose? Selling something "close" is better than missing a sale. They know they probably won't get it back, most claim all sales final once open.

Just have to be very careful, take nothing for granted! LOL

I always thought these old tractor kits were all made by the same company. Guess not.

Just put EFI on it and your carb worries are over......Sorry couldn't resist.

The carb kits that I have gotten for my 960 and 961 don't have an "idle jet" screw they have a low speed AIR screw. Out for more air and lean, in for less air, rich.

(quoted from post at 22:30:48 04/23/17) Sometimes, not saying it's your case, the carb has been changed
and you get the right kit for the "tractor", but not for the current carb.
I always order for the carb model number, not the tractor.
Then you still might have to deal with the land of almost right.

Click to expand...

Exactly. Carbs on 50 year old tractors aren't always the ones they came with from the factory.

Another thing to consider. How many carb kits do you suppose they sell, nation wide, in the US per year? Not all that many. And just how many for a particular carb? How about for a carb that they only made a couple of million at most 50, 60 or 70 years ago? What maybe a couple of thousand? At best? If made in the US they would not make a bunch and warehouse them, cost too much as they pay property taxes and know to a penny what each Square inch cost plus for inventory control all items have to be counted. And the cost of setting up to run of a thousand or so kits then switching a line over is high too. So that means taking the manufacturing off shore just to provide those kits to the dwindling market. Now with those kits being available on line the parts store has to compete for the sale. Now despite conventional wisdom you can get well may stuff out of China. But the buyer has to have a contract with a good company with close specifications. Looking for the cheapest supplier and specs go out the window. Then look at the market here. Bunch of old tightwads wanting the cheapest parts available. So many suppliers look for the cheapest route and wind up with junk kits.

Now I don't know if NAPA still markets the Echlin carb kits. Those use to be pretty good. The last time I bought a kit from NAPA it was the same one available from Tractor Supply Co. I was told that NAPA no longer sells a carb kit for a Ford N series tractor under a NAPA name. They had in fact ordered it from the TISCO catalog.

Rick

Read Showcrops post below. On most old tractor carbs the idle screw is out for lean and in for rich. This is just the opposite of most automotive carburetors.

I would disagree, most carburetors are idle screw lets in fuel, IH lets in air.

Not all IH idle screws are air bleeds. The ones where the idle screw is right up on the flange are mixture screws just like most trucks and cars.

I rebuild 50~100 Marvel Schebler carbs per year for Fords from
9N through the prior thousand series. Their idle screws adjust air.