Zenith Carb Adjustments

[jmoylan69]

ok guys, i've looked through all my TM's and i need help. im trying to find the specs and data or a pdf of something for my 1952 OA-331 gasser carb. The books i do have talk about adjusting if it needs it but does not give any specs for the adjustment.

If anyone has this and can pass it forward i'd be indebted!!

and im looking for information like the fuel system ALSO. reason is i've got a carb that fuel is starting to bubble or burble out of the sides etc. like its getting to much fuel. im wondering if I've got a bad return line system or something.

any information would be great

 

[73m819]

sounds like your float is sticking

 

[rcflyer70]

73M819 is correct - I had a similiar issue 18+ years ago when I bought my 1953 Studebaker (gasser). Take the time and rebuild the carb - I was able to get the carb kit locally. As for adjusting, I don't remember ever seeing a detailed description on how to adjust these carbs. I will look through my manuals - will forward anything useful.

 

[73m819]

does not have a RETURN ,idle is one full turn all the way in to start with, after warms up, adjust till it smooths out, total turns should be between 1 to 1 1/2 turns

 

[porkysplace]

You could have a chunk of rust or crud holding the needle valve from closing . Allowing the float bowl to overfill .

 

[JDToumanian]

does not have a RETURN

My OA-331 powered V-18A/MTQ has a fuel return line, and it is shown that way in the manual. The bypass valve and return line is above the primer handle on the fuel pump on the side of the engine, below the distributor. I don't really know what would happen if that line got clogged, but it would be easy enough to check. I do agree it sounds more like the float valve not sealing. These carburetors are very easy to rebuild.

I just noticed the title says Zenith carb... I thought they all used the Holley 885/FF(G). Your carb may not be original.

Jon

 

[73m819]

I gave the zenith idle, my truck motors #10 gives the specs. for these old carbs

 

[Barrman]

Um, I thought all the OA-331 engines had a Holley 885 carb? I know both of mine do. Anyway, here is a manual for the Holley:

Holley 885 / 885FFG carb manual

 

[JasonS]

Um, I thought all the OA-331 engines had a Holley 885 carb? I know both of mine do. Anyway, here is a manual for the Holley:

Holley 885 / 885FFG carb manual

My understanding is that it was an update; similar to the R6602's Zenith upgrade. The best carb is, IMHO, the holley 2bbl economaster.

 

[jmoylan69]

Thanks Jason. btw what do those holleys run now days?

 

[jmoylan69]

it looks like i've got either the zenith Model 28 or 28D but im not sure. anyone know these zeniths? a few mechanics around the area say zeniths are easy and good carbs. any Opines?

 

[jmoylan69]

hey all thanks for the posts. here are some pics. and I WILL check the needle and seat. This is the gasser I bought for 400 bucks. fuel leaks like nobodies business. im just curious if anyone has any print info on these.

 

[JDToumanian]

I have all the manuals for the old gassers. For general maintenance of the whole truck you need TM 9-8022, and it has tune-up info in it. The engine overhaul manual is TM 9-8023-1, there are copies of that on eBay right now. Both of those manuals only mention the Holley carb, for the Zenith carb only, the manual is TM 9-1826C... I just looked, it does cover the 28 series Zenith carbs.

Unfortunately I've never seen any of the good gasser manuals in electronic format, you gotta buy the books.

Jon

 

[jmoylan69]

found the zenith 28D float adjustment, 1.5" for those that may need to know