Jump to content

Help. Tillotson JR1A


Chris Coppi
 Share

Recommended Posts

Ok... bear with me... I'm a novice, but mechanically inclined.  I have this carb on my 1928 Chevy 2 door sedan.  It was leaking out the breather opening a lot.  I had it running on Saturday after a long cranking episode and then it ran out of gas and died.  After that, I could not re-start it.  Yes, the gas was a few years old and probably should have drained and replaced, but I didn't.  So, I took the carb off and was going to take it apart and clean it up, but I can't get the dang top off.  It's hanging up on something and only comes up about 1/8" and then stops.  I pulled the needle valve out of the bottom, but it's still jammed.  I think the big brass upward angled screw on the side needs to be removed and or the brass screw down the channel below that screw, but not sure.  Those are both screwed in super tight with possible lock tight on them. Hoping for some help here.  I'm sure there is some gunk in there.

Also need to know how to properly adjust the needle valve.  any help would be appreciated.  I'm in Covina Calif.

20220523_125432.jpg

20220523_125522.jpg

Link to comment
Share on other sites

To start with, wrong carburetor. If you must use a Tillotson, the JR-3A was the one Tillotson recommended for the 1928 Chevrolet.

 

GUESSING.

 

These units were certainly not the most expensive of the day; and are infamous for the zinc alloy in the pump cylinder (and the rest of the carburetor) warping. It may be that the pump is stuck in the bore, not allowing the carb to come apart. Try disconnecting the pump from the pump arm, which if the pump cylinder is warped, and the pump is stuck; will leave the pump in the bore, and allow the two castings to separate.

 

Second most likely cause would be the venturi (cast into the throttle body) has expanded, and is sticking in the bowl assembly.

 

As to adjustment, it probably doesn't matter; but Tillotson suggested 3/4 turn on the idle and 3 turns on the high speed as initial settings.

 

Jon

  • Like 2
Link to comment
Share on other sites

Thanks for the quick response.  I ended up taking the carb to a famous guy called Karl the carb guy in Duarte.  He will go through it and supposedly re-build/fix it.  Will see how it goes when I get it back.  Interesting that you say it's the wrong carb.  It's been on the vehicle for about 70 + years ever since my dad bought it. It's always ran ok with it, but always a bit of a challenge to start after sitting for some time.  Here's how it's been installed.  I think other parts of the car are from a 29 from what I recall my dad telling me.  I appreciate the heads up.  Maybe I can find a JR-3A some day and see how it works.

image.jpeg

Link to comment
Share on other sites

Chris - if you re-read my post, you will note the JR-3A was if you MUST use a Tillotson, which was an inexpensive aftermarket unit.

 

Would suggest, rather than spend money on another Tillotson, to look for a real carburetor, rather than a J.C. Whitney special.

 

Good luck with it.

 

Jon

  • Like 2
Link to comment
Share on other sites

To answer the question how to get it apart, you must remove that angling brass plug on the side, then there is a jet inside it to unscrew. It is abt 3/4 of an inch long and protrudes into the venturi  which is why it wont come apart. It's a Tillotson thing.

Edited by Oldtech (see edit history)
  • Like 1
Link to comment
Share on other sites

11 hours ago, carbking said:

Chris - if you re-read my post, you will note the JR-3A was if you MUST use a Tillotson, which was an inexpensive aftermarket unit.

 

Would suggest, rather than spend money on another Tillotson, to look for a real carburetor, rather than a J.C. Whitney special.

 

Good luck with it.

 

Jon

Why not make a suggestion of which carb is a must?

Link to comment
Share on other sites

8 hours ago, maok said:

Why not make a suggestion of which carb is a must?

 

There are no MUST carbs; but many, including the original, are better in every respect other than cost than the Tillotson.

 

Criteria before making a suggestion would be: desire (just get it running, drive it, show it), locality (flat like southern Illinois, hilly like Missouri Ozarks, or Pennsylvania mountains), engine modifications, budget.

 

Jon

Edited by carbking (see edit history)
  • Like 1
Link to comment
Share on other sites

Thank you all for your responses.  I ended up having  Carburetor Karl rebuild it for $120.  It was worth it for me since I'm not a specialist in Carbs and wanted to be sure it was done right.  I tried to take that brass screw out, but it was in there super tight and I didn't want to destroy it with the wrong screw driver etc.

This vehicle is not a show vehicle by any means and so I just want it running so that I can drive it around the block or local neighborhood.  I'm not about always having to have the perfect part.  This carb was installed before I was born and probably in circa 1940ish - way before my dad ever bought it.  : ).

 

On another note, I need to have the radiator re-built and I need to have the engine gone through to assure proper lubing etc.  Doesn't look like oil is getting up to the valves and they are rusty looking and the oil in the depression spaces is really black even though the oil on the dip stick is fairly clean.  Spark plugs were really black with lots of carbon build up.  I cleaned them up for now so I can see if I can get it started now at least.

20220521_133018.jpg

  • Like 1
Link to comment
Share on other sites

Hi Chris

thats great news about the carby. 28 Chevs are great cars and yes not slow for the period if they are running right. As for the oil on the rocker gear I’m sorry to say you are the Oiler! The pump does not pump oil up there in fact the pump only pump into troughs in the sump so the dipper on the big ends pick it up/ splash feed. Back to the rocker gear/valve train there should be a large felt under the rocker cover this needs to be kept oiled up. If you don’t already have an oil can get your self one and oil the rocker gear on a regular basis also remember to oil the front bush on the water pump. 
Best of luck with it all.

Cheers Ben

  • Like 3
Link to comment
Share on other sites

I have used a Tillotson carburetor in my 1928 Chevrolet for almost 15 years with good results (I don’t recall the model), until, after a long search, I finally found a good Carter RAKX0 unit to restore.
New kit, float an jets, now the Carter carburetor is working perfectly, exactly as in the original setting. 
I strongly suggest to not give up of the idea of having an original RAKX0 in your car.

My first antique car was a 1928 Chevrolet, Touring body, that I still own, very reliable automobile indeed.

Best, JRA

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...