Stromburg Carb

[Aaron F]

 Hi all, I'm working on  a B2D, all stock, engine was recently rebuilt I didn't do it, and someone put a rebuilt catb on it, it runs very good till you hit the hwy then you need to pukll the choke out about half way, then runs decent, I'm thinking rebuilt carb is junk so i got  akit and right now the carb is soaking in a can of carb cleaner, my question is as some one put a rebuilt varb on did they get the right one or did the rebuilder put the correct main jet in it, does anyone know what size the main jet would be, they are not stamped, or at least this one is not.

 

Thanks

Aaron

[50mech]

Mmm, more likely a fuel supply issue.

[Aaron F]

 I thought of that also, but upon opening the carb it was pretty dirty inside, odd as it was only about a year old and the truck has been down for half of that, the fuel pimp has a screen i it and the glass bowl had some crud in it, the tank is clean as i out a new send in it and looked inside, but one problem at a time the main jet size kinda makes me wonder.

[50mech]

I can get you in the neighborhood.

Two vehicles I found using the bxv-3 or bxvd-3 carbs  (3-100b or 3-97) like yours would have.

The 39 d11 used an .058 main jet on a 218

The d29 ran a 230 and used an .061 jet

Edited August 1, 2020 by 50mech

[Aaron F]

OK thanks, I wish they hadn't put a rebuilt carb on and just left the old one to go thru, it is marked as 3-99, but I'll run a pin mic in this jet and see what it is.

Thanks

Aaron

[Pete]

I've been looking into jet sizes lately. This may or may not help.

 

My 39 Plymouth P8 Carter B&B carb came standard with a .053 main jet. After whatever engine mods by previous owners it seemed to run a bit lean, but close. One of those mods was boring the engine out from 201 to 218.

 

I recently had the engine rebuilt, which included cleaning up the cylinders by .030 and higher compression by further shaving the 1950s Dodge cylinder head. It ran even a bit more lean, so I increased the jet size to .055.

 

After that, the plugs looked better, but not where I would like them, so I'm going to go to .057 and see where I am.

 

Pete

 

[50mech]

3-99 is actually right and correct for the vehicle, idk why I put 3-97.

It's a bxvd-3.

Edited August 2, 2020 by 50mech

[Aaron F]

Ok, that helps, I'll get it back together and see what it does, I've no idea why they replaced it to start with, it could have been for this problem for all I know.

 On Pete's question I had the same problem with a 261 Chevy, plugs didn't look right, I drilled the mains out a little it helped but not a lot, what I'm told is that todays crap gas doesn't read on the plugs like the older gas did.

[Pete]

FYI: I've run only non-ethanol gas since the rebuild, so I think I've good on reading the plugs. As I like to tour I will eventually have to fill up with ethanol gas. Another reason to open it up a bit more.

 

Pete

 

[Aaron F]

Main jet miced at .057, so i reamed it to .061, it runs better but still need slight choke when floored for take off, at speed it runs fine it just seems to stave a little when going thru the gears at a full throttle, I'll check fuel pump volume, and drain and check tank and line and see where that leads me.

[50mech]

Hmm, vacuum power piston?....or power bypass jet....if the main was an .057 perhaps the rebuild kit came with the power bypass jet to match the .057 main?

 

It's supposed to open up when vacuum gets down around 4-6inhg 

And I imagine you already checked to see the accelerator pump works.

Edited August 4, 2020 by 50mech

[Aaron F]

Vacuum power piston on this one, what I wondered about was the Power by pass jet, it has the spring loaded needle in it and that one does not stick up thru the jet like the one on the acc pump does also it has a stamp on it the best I could see was 56, the one under the acc pump looked to be 00, the acc pump works as it does not stumble but I'll check just with it sitting and see that it does squirt, could it be possible that the power jet and the acc pump by pass were mixed up,I put them back the way they came out but that doesn't mean anything.

 

Thanks

Aaron

[50mech]

33 minutes ago, Aaron F said:

Vacuum power piston on this one, what I wondered about was the Power by pass jet, it has the spring loaded needle in it and that one does not stick up thru the jet like the one on the acc pump does also it has a stamp on it the best I could see was 56, the one under the acc pump looked to be 00, the acc pump works as it does not stumble but I'll check just with it sitting and see that it does squirt, could it be possible that the power jet and the acc pump by pass were mixed up,I put them back the way they came out but that doesn't mean anything.

 

Thanks

Aaron

I think you found it. The power by pass jet is supposed to have the valve sticking up through, where the accelerator pump bypass should not. They're mixed up for sure.

 

Actually the accelerator one is supposed to open downward at a certain pressure. While the power bypass opens downward when the piston depresses it.

 

Accelerator pump jet should be no.56

Edited August 4, 2020 by 50mech

[Aaron F]

AHHHH, I wondered about that when i took it apart, but thats the way it came out so i put it back the same, I'll swap those around and see what happens.

 

Thanks

 

AA

[Aaron F]

I didn't check the acc pump by hand when i put it together, it did squirt fuel and did not hesitate on accleration but on the bench it was a poor spit of fuel, after moving the valves around it put out a steady stream and runs like a watch now, I would have chased this glitch for days had you not asked about the power valve.

 

Thank you

 

Aaron

[50mech]

From the description of the behavior I thought that maybe the size was off or piston was stuck for what would be the power valve or step up in what I'm used to.  Never occurred to me they'd be swapped around. Glad you figured it out.

[Aaron F]

Thank you

I was going to put a picture of the truck on here but can't figure out how to resize the pic to get it on here.