Zenith Stromberg Mixture Adjuster

[smcmanus]

Where can I find the special tool for adjusting my Zenith Strombergs? It is a allen wrench type thing with a sleeve around it that is put down through the damper hole to adjust the metering valve needle. Who has one?

Thanks
Steve

 

[tony barnhill]

Moss & VB carry it

 

[DrEntropy]

Steve; in a pinch you can use a long 3mm Allen wrench. But you need to take the air cleaner off to hold the piston motionless when making adjustment or risk twisting (and damaging) the diaphragm. If the little O-ring is not seized in the bore this works quite well. And ~small~ changes in the adjustment go a long way. 1/8 turn can make a BIG difference.

Clockwise viewing from top enrichens the mix.

 

[smcmanus]

I took the tops off the carbs to withdraw the whole assembly. I was able to adjust the metering valve on the front carb but the rear is stuck tight. Any ideas? How does the metering valve come out of the cylindrical doo-hickey?

Thanks
Steve

 

[DrEntropy]

The O-ring in the rear piston is likely stuck in its bore. They tend to age harden and "freeze". The adjuster assembly is held in with a set-screw at the side of the piston. Remove the setscrew and GENTLY tap the assembly out from the top (I like to use a wood dowel rod for this). The assembly then can be disassembled/cleaned by unwinding the adjuster (stuck in your case). The needle is under spring tension in the sleeve the adjuster threads into.

Sounds like you should rebuild those things, Steve. They'll need the little O-rings at the very least, and once you're "into" it you may as well do the whole job. Get a set of rebuild kits from Joe Curto. Most of the "vanilla box" kits are inferior.

 

[smcmanus]

I have "rebuilt" the carbs. I did not remove the metering needles at the time. As a ZS neophyte I do not know what I am doing so I wanted to be sure before I whacked anything. The set screw is out and I have attempted to drive the needle assy out but it won't budge. It is soaking in PB Blaster right now. I will attemp again tomorrow.

Thanks
Steve

 

[smcmanus]

Well I whacked it. Nothing moved, so I beat the crap out of it. Here is the result!! I still don't see how it helps but I'm certain this is not the desired result. Delrin washer? I don't need no stinking delrin washer.

Who has some spare JH ZS carbs?

Have a nice day
Steve

 

[DrEntropy]

ACK!!! The oil tube should be swedged in the piston, the dowel should fit inside the tube to only drive out the needle assembly! I ~assumed~ you had an illustration (VB or Moss catalog at the least) to view, so-as to see the exploded view of the needle assembly -inside- the tube... never gave a THOUGHT to driving the tube out of the piston. <STUNNED!>

You could likely get away with just a piston replacement. Not as critical as SU piston/chamber matching.

And the needle there looks to have enough green fuzz (old gas and moisture!) to render the carb untuneable. How long ago did you "rebuild" 'em?!?

 

[smcmanus]

"ACK!!! The oil tube should be swedged in the piston, the dowel should fit inside the tube to only drive out the needle assembly! I ~assumed~ you had an illustration (VB or Moss catalog at the least) to view, so-as to see the exploded view of the needle assembly -inside- the tube... never gave a THOUGHT to driving the tube out of the piston. <STUNNED!>"


Dr E.

I know it seems unlikely but I was whacking on the needle assembly and I do have pictures. Shortly, I will use the torch and either melt it or get it apart. Yes, it is actually very clean. I suspect it was either super glued or secured with loctite red. When I rebuilt the carbs last week, I could not get the needles out of the vacuum valves.

I wondered why someone would spend so much money on a project only to abandon it. Now I know!

Thanks and have a nice day
Steve

 

[DrEntropy]

WOW! Mebbe it would be beneficial to get another set of carbs. That's kinda indicative of some strange abuse. Almost afraid to ask what else you've found! /bcforum/images/%%GRAEMLIN_URL%%/blush.gif

 

[smcmanus]

Dr E.

It melted and it did not come apart. A fellow in MN has come through with a spare set of carbs. I only need the parts in question but certainly like to have spares. There was a complete car on ebay near here that I completely missed out on; it sold for cheap. I wish I had it here. I found may things wrong, like zero clearance on the valves and every seal and gasket leaking. I have gone through almost everything but I enjoy working on new things. I appreciate the advice.

Have a nice day
Steve

 

[DrEntropy]

I see the evidence of the valve adjust and carb cleaning. Where'd you go for shims?

 

[smcmanus]

I traded with some other folks. I needed thinner shims due to gasket removal (no clearance to begin with!) and they needed thicker because they were going with regrinds. I also ended up buying some and found that Delta had them for $2.25 ea which isn't too bad. The valve adjust on the Lotus 907 is tedious but would take much less time if there was a shim assortment available.

Have a nice day
Steve

 

[DrEntropy]

/bcforum/images/%%GRAEMLIN_URL%%/wink.gif

Delta, Bean, RD Ent... all have most of what you'll want. I have a fairly large collection of 'em. Next time you do it, if you're in a spot and I have the size you need, I'll swap out with you. Too bad the geography is so awkward.