Stromberg 2BBL home tuneup tips pls? ’67 Monaco 383

[DJAstral]

Hi there, me again ...
My ‘67 Monaco looks to have its original Bendix Stromberg 3-276 WWC and I was wondering if any of you had any home tuneup, adjustment advice for best performance, mpg, mixture, idle, kickdown operation, & Cold-start.

Nobody does old school stuff like this round here anymore, it’s all ECU stuff these days.

As much as I’d love to upgrade to a modern 4 BBL & intake (Edelbrock 650cfm probably) when funds allow, I just want to try any see if I can sweeten her up as much as possible without rebuilding this 2BBL which seems ok, but probably suffering from 4 years non-use prior to me getting her last year, and needs a tweak to get the best out of her. Have ran carb cleaner through & lubed obvious moving parts so far.

Many thanks once again.
Simon
from the Scottish Borders, UK.

 

[GJS]

Is it doing anything particularly bad? I ask because (to my knowledge) those carbs don't offer or require a lot with regards to tuning. If it's original it may just be time for a rebuild.

So, is your wagon a 67 with a 68 front end or?

 

[DJAstral]

Hi, nothing too bad other than I have a suspicion the mixture isn’t quite right or something. Exhaust fumes smell pretty strong but not at all visible, chrome slotted exhaust tips blacken up after a run. She starts fine when hot but takes about 16 pumps of the gas pedal when cold & stays running after about four tries. Seems a bit uneven at higher speeds & pops a bit on deceleration.

Regarding the front end I think it may be a ‘68 Polara grille someone fitted in the past (with fencing wire!) but I kinda like the look of it even if it’s not original.

 

[GJS]

Hi, nothing too bad other than I have a suspicion the mixture isn’t quite right or something. Exhaust fumes smell pretty strong but not at all visible, chrome slotted exhaust tips blacken up after a run. She starts fine when hot but takes about 16 pumps of the gas pedal when cold & stays running after about four tries. Seems a bit uneven at higher speeds & pops a bit on deceleration.

Regarding the front end I think it may be a ‘68 Polara grille someone fitted in the past (with fencing wire!) but I kinda like the look of it even if it’s not original.

I’ve owned a 67 and a 68... love em both!

With regards to the carb, I’ve basically just rebuilt them when I got cars as a rule especially if they sat for an extended period. There’s a lot of stuff to gum up in there and based on how long it sat and even the pictures of the body, I’d say that could be a rather large part of your issues.

 

[CBODY67]

In general, not a lot to go wrong with those carbs. Set the idle mixture, starting at 1.5 turns outward on the idle mixture screws, with a hot idle rpm of about 600rpm or so, as I recall.

Make sure the base plate nuts are snugged-down nicely.

As far as the cold starting issues, when the engine is cold, make sure the automatic choke flap closes fully, then is pulled open a bit as the engine starts by the choke pull-off diaphragm. With the engine cold and everything at an ambient air temp of 70 degrees F, the choke flap should just close, easily and gently, if it's got more "pressure" than that, then the choke thermostat in the intake manifold probably needs to be backed-off a notch or two. With age, those thermostatic springe tighten-up, so if you set it to factory specs, or it is still at factory specs, it'll not let the choke open soon enough to not over-choke the engine.

Back when the cars were newer and we still had leaded fuels, it was common to see the light gray coloring at the end of the exhaust pipes. Which indicated a normal carb mixture situation. BUT when the lead left, the pipes would color "black" and fluffy, typically. As my '77 Camaro did when it was new. So, what you might perceive is a too-rich mixture, from the rear pipe coloring, might be completely normal for unleaded gasoline (ethanol'd or not).

A better check might be to look at the spark plugs instead.

But do ensure that the hot base idle timing is correct for the car. That the idle mixture is set to specs. That the spark plugs are gapped correctly and reasonably clean, as to accumulation or deposits on the insulator and ground electrode.

Also look for vacuum leaks, including the vacuum advance can.

You can set the accel pump arm in the long slot for a bit longer accel pump shot, but generally, the center slot will work just as well, from my own experiences in seeking a bit more performance on out '66 Newport 383 2bbl when it was new (and I was in high school).

Do the carb "kit" AFTER you've done everything else to make sure things are adjusted right and such. By observation, unless the innards are really gunked-up, the carb "kit" deal gave us more peace-of-mind that all was well, with little improvement in performance, if any at all, back then.

It will not hurt to spray the carb with a good carb cleaner, in the venture area and on the outside. When we'd get the '66 Newport tuned-up at the local Chrysler dealer, back then, the tech would get a can of solvent and splash it around onto and into the carb. "Solvize" is what they termed it. This would easily wash the accumulated varnish and such off of the carb venturis and clean up the choke flap to make sure it was free to move.

DO also make sure those well plugs in the bottom are tight and do not leak. They plug passages which go to the float bowl, so when they leak, it can get "firey" under there. On some, which use a staked-in ball bearing surrounded by a sealing solder, modern ethanol'd fuels degrade the solder and the balls can fall out. Not good! Just spray everything down to get it clean and watch that area, for good measure.

Just some thoughts,
CBODY67

 

[DJAstral]

I’ve owned a 67 and a 68... love em both!

With regards to the carb, I’ve basically just rebuilt them when I got cars as a rule especially if they sat for an extended period. There’s a lot of stuff to gum up in there and based on how long it sat and even the pictures of the body, I’d say that could be a rather large part of your issues.

I’ve owned a 67 and a 68... love em both!

With regards to the carb, I’ve basically just rebuilt them when I got cars as a rule especially if they sat for an extended period. There’s a lot of stuff to gum up in there and based on how long it sat and even the pictures of the body, I’d say that could be a rather large part of your issues.

Yes, there’s something about these old largely overlooked old beasts I love!
I’ve even had a guy shout ‘What the Fffffff*€* is that?’ when I was trying to find a big enough parking space at night once.
I’ve ordered a Hygrade rebuild kit, based on your suggestion as it would certainly be a piece of mind to do this when I’m feeling brave and more knowledgeable than I am now. YouTube hasn’t yielded anything yet as I’d hoped, as I struggle a bit otherwise.

 

[DJAstral]

In general, not a lot to go wrong with those carbs. Set the idle mixture, starting at 1.5 turns outward on the idle mixture screws, with a hot idle rpm of about 600rpm or so, as I recall.

Make sure the base plate nuts are snugged-down nicely.

As far as the cold starting issues, when the engine is cold, make sure the automatic choke flap closes fully, then is pulled open a bit as the engine starts by the choke pull-off diaphragm. With the engine cold and everything at an ambient air temp of 70 degrees F, the choke flap should just close, easily and gently, if it's got more "pressure" than that, then the choke thermostat in the intake manifold probably needs to be backed-off a notch or two. With age, those thermostatic springe tighten-up, so if you set it to factory specs, or it is still at factory specs, it'll not let the choke open soon enough to not over-choke the engine.

Back when the cars were newer and we still had leaded fuels, it was common to see the light gray coloring at the end of the exhaust pipes. Which indicated a normal carb mixture situation. BUT when the lead left, the pipes would color "black" and fluffy, typically. As my '77 Camaro did when it was new. So, what you might perceive is a too-rich mixture, from the rear pipe coloring, might be completely normal for unleaded gasoline (ethanol'd or not).

A better check might be to look at the spark plugs instead.

But do ensure that the hot base idle timing is correct for the car. That the idle mixture is set to specs. That the spark plugs are gapped correctly and reasonably clean, as to accumulation or deposits on the insulator and ground electrode.

Also look for vacuum leaks, including the vacuum advance can.

You can set the accel pump arm in the long slot for a bit longer accel pump shot, but generally, the center slot will work just as well, from my own experiences in seeking a bit more performance on out '66 Newport 383 2bbl when it was new (and I was in high school).

Do the carb "kit" AFTER you've done everything else to make sure things are adjusted right and such. By observation, unless the innards are really gunked-up, the carb "kit" deal gave us more peace-of-mind that all was well, with little improvement in performance, if any at all, back then.

It will not hurt to spray the carb with a good carb cleaner, in the venture area and on the outside. When we'd get the '66 Newport tuned-up at the local Chrysler dealer, back then, the tech would get a can of solvent and splash it around onto and into the carb. "Solvize" is what they termed it. This would easily wash the accumulated varnish and such off of the carb venturis and clean up the choke flap to make sure it was free to move.

DO also make sure those well plugs in the bottom are tight and do not leak. They plug passages which go to the float bowl, so when they leak, it can get "firey" under there. On some, which use a staked-in ball bearing surrounded by a sealing solder, modern ethanol'd fuels degrade the solder and the balls can fall out. Not good! Just spray everything down to get it clean and watch that area, for good measure.

Just some thoughts,
CBODY67

Hi there, really appreciate all that useful advice which gives me bit of focus. Interesting what you say about the modern fuels not colouring the exhausts the same, I always used that as a mixture guideline back in the day when we had real fuel.
I’m going to go through the steps you suggest and have also ordered a rebuild kit as a backup.
I will post any progress, and hopefully won’t make it worse by messing with the screws at the front base of the carb body in the photo I posted above, which I assume are the screws you mentioned?
Thanks again.

 

[GJS]

Yes, there’s something about these old largely overlooked old beasts I love!
I’ve even had a guy shout ‘What the Fffffff*€* is that?’ when I was trying to find a big enough parking space at night once.
I’ve ordered a Hygrade rebuild kit, based on your suggestion as it would certainly be a piece of mind to do this when I’m feeling brave and more knowledgeable than I am now. YouTube hasn’t yielded anything yet as I’d hoped, as I struggle a bit otherwise.

There should be a blow up diagram with the kit, which helps. It’s pretty easy to grab a Factory Service Manual off eBay or for free (if you don’t mind pdf format) here MyMopar - Mopar Forums & Information - Service Manuals
That’ll have all the info you need, for sure.
Good luck! Be gentle with it, get everything real clean and you should have a problem. Those two barrels didn’t have much to em.

 

[69 300 vert]

Cold-start.

16 pumps, sounds like my old Fury. Choke needs to be adjusted. But you'll never get it right if the exhaust crossover in the intake manifold is clogged. No exhaust heat to open the choke, so everybody sets it to open when warm and puts up with hard cold starts. VERY common on mopar V8's even when near new. I'd suggest pulling the manifold and carb, checking and cleaning the manifold and a fresh carb kit for the carburetor.

 

[Gerald Morris]

I have an issue with the carburetion turning to **** when the engine is warmed up. Better do a new thread.

 

[DJAstral]

16 pumps, sounds like my old Fury. Choke needs to be adjusted. But you'll never get it right if the exhaust crossover in the intake manifold is clogged. No exhaust heat to open the choke, so everybody sets it to open when warm and puts up with hard cold starts. VERY common on mopar V8's even when near new. I'd suggest pulling the manifold and carb, checking and cleaning the manifold and a fresh carb kit for the carburetor.

Thanks very much for this - I’ll do these things. Meanwhile, not sure about where the horizontal push slide slotted rod in the foreground should be adjusted to & what it actually does.
Also, where the rod that pushes up through one of the three vertical slots (what do they even do?) in that plate should be set by bending... confused & feeling stoooopid!

 

[Gerald Morris]

Best favor you can do for yourself w a WWC carb is to put it on a MANUAL choke. VERY EASY to do. Then, you can choke it when you want to, not when sundry physical laws operating in old springs and such allow it. You can get a decent manual choke cable and mounting kit for $10-15.

 

[DJAstral]

Thanks Gerald, I assume it's just a good quality universal Manual Choke Kit I need?
Also, are there any pointers/threads/videos you could let me know about how to do this - the car starts up fine if I manually close the flap & releases itself ok but it would be much better to have the manual choke like you suggest, I'm just ignorant of how to do this having only had the car a year.

 

[GJS]

Thanks Gerald, I assume it's just a good quality universal Manual Choke Kit I need?
Also, are there any pointers/threads/videos you could let me know about how to do this - the car starts up fine if I manually close the flap & releases itself ok but it would be much better to have the manual choke like you suggest, I'm just ignorant of how to do this having only had the car a year.

I'd say if it opens up as the car warms up, switching to full manual choke might be overkill? The choke is supposed to close with your initial accelerator pump .. the spring in the manifold is cold so it snaps the linkage and choke closed, as the vacuum comes up, the vac can on the back left of the carb works to pull the choke open against the spring. As the spring warms it gives to the vacuum and the choke slowly opens.... I'm not all that experienced with Strombergs, my cars all came with Carters, but I believe that's the gist of it.

Again, from the looks of the carb, it's gunky and therefore there are a number of places on the external linkages where it could be hanging up. Again also; if the choke is opening on it's own, it's likely that your vac can and spring are all working properly. I still think a rebuild is in order but if you want to convert to manual, the kit you'll need will likely replace that vacuum can on the back left of the carb with a bracket for the cable shield to fasten to then the linkage going to the manifold has to be eliminated. the cable then passes through the firewall and is mounted under the dash somewhere ... be sure you disconnect your battery when passing it through.

Thanks very much for this - I’ll do these things. Meanwhile, not sure about where the horizontal push slide slotted rod in the foreground should be adjusted to & what it actually does.
Also, where the rod that pushes up through one of the three vertical slots (what do they even do?) in that plate should be set by bending... confused & feeling stoooopid!

That is your throttle linkage. It basically tells your engine when and how hard to shift. It also triggers downshift at wide open throttle. You REALLY don't want to mess with that without a factory service manual.... it'll show you how to set it and basically everything else you'd need to do to that thing .... in fact, you REALLY need to get a factory service manual. There's a PDF version for free here:
MyMopar - Mopar Forums & Information - Service Manuals
or you can find em on ebay regualrly.

 

[Gerald Morris]

Thanks Gerald, I assume it's just a good quality universal Manual Choke Kit I need?
Also, are there any pointers/threads/videos you could let me know about how to do this - the car starts up fine if I manually close the flap & releases itself ok but it would be much better to have the manual choke like you suggest, I'm just ignorant of how to do this having only had the car a year.

I recall buying an Edelbrock manual choke kit, though any such consisting of a 6' steel cable with a knob and mounting L bracket on one end, and about a foot of bare steel wire on the other to bend, cut, and attach to your carburetor's auto choke arm will do. I can provide pics for you tonight if you need to look at how I did my job. This might help.

No 2 ways about it; having a manual choke gives you a degree of control over your fuel/air delivery superior to any automated setup and THIS HELPS! It also controls your throttle better, as the "cold engine throttle" likewise is set by the choke, giving you greater control of your starting idle. I run with my curb idle at ~550 rpm and the cold idle ~ 1000 rpm. By having this subject to a little knob under your dash, you can decide precisely when you want your engine idling normally, or if you want the fast bunny idle, for like charging a slightly low battery or such. Best of all, you can turn that fast idle OFF at your whim too, instead of having to "fan" the gas pedal to make that fast idle cam drop out.

Its VERY EASY to put a manual choke on that WWC carb too. The attachment is fully reversible, should you for some reason want to restore the original stove and rod choke Mopar used with some good effect for a decade +. If you need to see a pic or two to help you decide, let me know.

 

[DJAstral]

I recall buying an Edelbrock manual choke kit, though any such consisting of a 6' steel cable with a knob and mounting L bracket on one end, and about a foot of bare steel wire on the other to bend, cut, and attach to your carburetor's auto choke arm will do. I can provide pics for you tonight if you need to look at how I did my job. This might help.

No 2 ways about it; having a manual choke gives you a degree of control over your fuel/air delivery superior to any automated setup and THIS HELPS! It also controls your throttle better, as the "cold engine throttle" likewise is set by the choke, giving you greater control of your starting idle. I run with my curb idle at ~550 rpm and the cold idle ~ 1000 rpm. By having this subject to a little knob under your dash, you can decide precisely when you want your engine idling normally, or if you want the fast bunny idle, for like charging a slightly low battery or such. Best of all, you can turn that fast idle OFF at your whim too, instead of having to "fan" the gas pedal to make that fast idle cam drop out.

Its VERY EASY to put a manual choke on that WWC carb too. The attachment is fully reversible, should you for some reason want to restore the original stove and rod choke Mopar used with some good effect for a decade +. If you need to see a pic or two to help you decide, let me know.

Thank you for that, much appreciated.

 

[DJAstral]

I’ve just had the carb completely cleaned & overhauled with all new Hygrade parts.
However... it’s now not firing on all cylinders & is down on power. Idles fine, it just becomes obvious when you drive it.
Any help would be gratefully appreciated as always.

 

[Gerald Morris]

I’ve just had the carb completely cleaned & overhauled with all new Hygrade parts.
However... it’s now not firing on all cylinders & is down on power. Idles fine, it just becomes obvious when you drive it.
Any help would be gratefully appreciated as always.

Have you checked the timing? How about the vacuum advance? What sort of ignition do you have? Did you set the idle jets as per the FSM? Is the float good? I don't think the Hygrade kit has a new float....

 

[DJAstral]

Hi there, I’m taking it back to the garage first thing this morning here in Scotland, UK. He says he was going to try the fast idle setting first.
We both have no knowledge of this carb unfortunately. I’ll mention vacuum advance, no idea what this is though.
The timing was good & set before the carb rebuild (12 deg BTDC I seem to remember) I have Pertronix Ignitor basic kit fitted.
I’ll mention about the idle jet setting (are they the two screws at the base on the front?)
No float in the kit, but looks ok.
Any pointers would be much appreciated. The setting for the lever that has connects to the three slotted lever that opens that bowl thing at full throttle also is causing confusion - if you know what I mean?
Here in the UK, especially where I live in the country, there is no knowledge of this sort of old car so I’m in a panic as I am hosting my first American Car show this coming weekend in Kelso, Scottish Borders.......... hellllp?!!!

 

[DJAstral]

Well, it’s still exactly the same. No power & very lumpy not firing on all 8... The thick carb base mounting gasket/flange had disintegrated during removal so he just put the thin card ones back & it’s sitting lower & closer to the inlet manifold.... could this be causing it please? My first car show I’ve organised & this weekend & I want to be there with mine - panic setting in now!