Author Topic: Stromberg Carb and Elevation  (Read 328 times)

67tank

  • Full Member
  • ***
  • Posts: 230
Stromberg Carb and Elevation
« on: December 28, 2021, 10:56:36 AM »
When I brought my halftrack from California (10 feet above sea level) to the mountains of Colorado (7200 feet above sea level) I knew I would have to make some adjustments.  It was running rich and bogging down as I would drive around - to the point that I would have to be in 4-Low to get up minor hills. 

Did the basics - Cleaned the fuel filters, adjusted the timing a few degrees etc but finally decided to rebuild the carb and re-jet.  Frustrating because I had  this done by "Then & Now" during the restoration process only 200 miles previously.  Reached out to Stromberg-97 in England and got the following reply

"I found a sheet for this in an old binder we have and yes it quotes 0.058 as the main jet size, with a number 56 power valve (93 in this diagram) .   Both are BIG jets compared with what we usually see on our 97 range. Your White is probably overfuelling as the air is thinner, so the mixture is off. Ford used to advise 2 jet sizes down for 5K to 10k elevation. Most folks we have feedback from in Colorado are looking at around the same - 2 to 3 smaller than stock on the mains and maybe two numbers smaller on the PV. It might help to adjust the idle screws too - screw them in a little.
A set of main jets would be $10.95 and a power valve is $14.25 plus a little shipping from our warehouse in Kentucky.  On this lower revving application I would try the mains first, but you can decide. You could try say some 56 main jets and a number 58 or 60 PV. "

I ordered jets a size down (56) and two different PV (installed the PV 60 to start)  Had a local carb expert rebuild with the new components - glad that i did.  The needle jets were gunked up, the float was bent, and the adjustments were off -

Everything is back together - just waiting for my hyrdovac to be returned from White Post Restorations out of Virginia - got tired of having to bleed the brakes every 6 months or so - had it sent to theses guys for rebuild/re-sleeve. 

Will let you know how it runs with the new adjustments.   
Pat
1941 M2A1 (under restoration)

67tank

  • Full Member
  • ***
  • Posts: 230
Re: Stromberg Carb and Elevation
« Reply #1 on: December 28, 2021, 10:58:20 AM »
Diagram
Pat
1941 M2A1 (under restoration)

coreyelliott

  • Sr. Member
  • ****
  • Posts: 325
Re: Stromberg Carb and Elevation
« Reply #2 on: December 28, 2021, 09:37:03 PM »
This is great to hear, Pat.  I am really looking forward to hearing your results!  I'm chasing down an issue with running just a bit rich even though we are only around 4000' here.  Did the jet removal tool come with the new jets?

Thanks,

Corey
« Last Edit: December 31, 2021, 06:22:56 PM by coreyelliott »
1941 Autocar M2A1 (M2-13)

67tank

  • Full Member
  • ***
  • Posts: 230
Re: Stromberg Carb and Elevation
« Reply #3 on: December 31, 2021, 02:23:40 PM »
Corey
The tool was $30 from Stromberg - VERY glad that I purchased it. 
Pat
1941 M2A1 (under restoration)