My 8N

This is mostly a curious question. Awhile back a few people did some testing on Ford front distributor points, which ones good, which ones bad. I have another question, these after market carbs, I know rebuilding an OEM carb is the best thing to do but, what exactly is the problem or problems with the aftermarket carbs, besides them maybe being out of adjustment, just being curious, I'm a sponge for information.

What's wrong w/ them is that it's a crap shoot.

Some still work after a year or so and many don't.

Of course, we all hear about the ones that don't work.
75 Tips

I bought a running 8n with loader, and a brand new aftermarket carb( silver turd).Took the loader off, pulled the hood, rigged a temp fuel tank.

Engine started ok. When warmed up, ran ok to about 5/8 ths throttle, 1500 - 1800 rpm, then started missing, or stumbling.it would reach 2200 rpm, but kept missing, or stumbling. These tests were in neutral, in the shop.

Put a known good marvel schebler on it , and it ran perfectly.

Took the silver aftermarket turd apart,it was brand new. Checked the passages and jets with wypo torch wire cleaners. The sizes were compatable to the MS carb. Except the economizer jet was .065 or bigger. Its in the picture, on the wire thats .065. Stock is in the .046 range. All the passages were clear. The bowl halves were flat and true.
I put it back on, it ran the same. Flat spot at 5/8 ths throttle. Pulling the choke didn't fix it. Bet I took it off 4 or 5 times tinkering away with it.

Gave up, found a rebuildable Ms carb in my spare parts bin, and used the turd for parts. The rebuilt Ms ran perfectly with the choke shaft, and float.

Didn't want to try to unscrew a jet out of a good Ms, to experiment on the silver turd.

John

I would solder it shut & re-drill it.

I've found that it is mostly the cheap clones that are junk. The better aftermarket clones seem to be OK. Zenith makes decent product but so many Cheena clones are out there now it, is, as Bruce said, a crap shoot. Zenith is no stranger to Ford -they supplied carbs to earlier vehicles, but know that if it isn't marked as such it isn't a Zenith. The OEM Marvel-Schebler is no longer in business so best bet is to just rebuild them. Parent company Borg-Warner is still around but not the M/S carbs. If a M/S carb isn't marked as such it isn't either. I see many new units on ebay marked as a M/S carb and it isn't, can't be new. ya gotta do your homework and be careful where you buy from.

Tim Daley(MI)