Stromberg OF choke question

Discuss all things Model T related.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules

Topic author
Mark Osterman
Posts: 650
Joined: Mon Jan 07, 2019 10:18 pm
First Name: Mark
Last Name: Osterman
Location: Rochester, NY

Stromberg OF choke question

Post by Mark Osterman » Sun Feb 24, 2019 4:28 pm

I finally got around to installing the Stromberg OF I bought from Bruce Compton at Hershey two years ago. It had been an older restoration by Stan and when he saw a picture of it, offered to update the plugs to how he does them now. So, it’s been around the block.

I did the preliminary adjustments over again since I wasn’t sure if they had been moved from handling. Used a small brass tube with a pipe fitting and silver soldered a 1/4” brass barbed end for gas line tubing to connect it to the steel gas line. Works fine. Steppd on the starter button and in four revolutions it came to life and actually idled very nicely right away. It was warmer here today and I was wondering what I would do if I needed to choke. It does have an arm to the choke wire that comes from the radiator. But what about when sitting in the car. It’s clear that the stock pull knob won’t work the way it’s configured. And then there is that interesting fitting on the back of the OF that allows adjustment of the butterfly through a cable to the steering column, but this appears to be for regulating a rich mixture for driving rather than a momentary choke when starting. What are others out there doing for choke?

So, I did a little fiddling with the idle and high speed adjustments but need to spend some quality time with it on a better day. Also need to do some better fitting of the throttle rod as it’s binding at the highest speed settings. We are expecting 70 mph winds soon and I just wanted to go a couple of times around the neighborhood. Feels pretty good and I see a smoothness in acceleration. Nothing yet on the high end that seems better than the straight through NH I just removed.


MichaelPawelek
Posts: 76
Joined: Sun Jan 06, 2019 2:01 pm
First Name: Michael
Last Name: Pawelek
Location: Brookshire, Texas
Board Member Since: 1999

Re: Stromberg OF choke question

Post by MichaelPawelek » Sun Feb 24, 2019 7:16 pm

Here is the set up I’ve had on my ‘19 for the past 20 years. The vertical rod is just a piece of coat hanger....

Image


Topic author
Mark Osterman
Posts: 650
Joined: Mon Jan 07, 2019 10:18 pm
First Name: Mark
Last Name: Osterman
Location: Rochester, NY

Re: Stromberg OF choke question

Post by Mark Osterman » Sun Feb 24, 2019 8:04 pm

Ohh .. ok, so you are connecting it to the arm meant for a cable. This isn’t made for choking ... but for an adjustment for making a lean mixture for driving. So I guess that adjustment isn’t so important then. Yes, I have the original rod for that bell crank to the old carburetor. Thanks.

User avatar

Mark Gregush
Posts: 1662
Joined: Sat Jan 05, 2019 1:57 pm
First Name: Mark
Last Name: Gregush
Location: Portland Or
Board Member Since: 1999

Re: Stromberg OF choke question

Post by Mark Gregush » Sun Feb 24, 2019 8:33 pm

I know the voices aren't real but damn they have some good ideas! :roll:

1921 Huckster
1925 Cut down pickup


MichaelPawelek
Posts: 76
Joined: Sun Jan 06, 2019 2:01 pm
First Name: Michael
Last Name: Pawelek
Location: Brookshire, Texas
Board Member Since: 1999

Re: Stromberg OF choke question

Post by MichaelPawelek » Sun Feb 24, 2019 8:40 pm

Mark Osterman wrote:
Sun Feb 24, 2019 8:04 pm
Ohh .. ok, so you are connecting it to the arm meant for a cable. This isn’t made for choking ... but for an adjustment for making a lean mixture for driving. So I guess that adjustment isn’t so important then. Yes, I have the original rod for that bell crank to the old carburetor. Thanks.
Yes, both ends of the “y” arm on the carburetor are for the choke plate. Top arm for rod out to the radiator and bottom arm for wire to lever near steering wheel for choking while in the driver’s seat.


Bruce Compton
Posts: 144
Joined: Thu Jan 10, 2019 11:23 am
First Name: Bruce
Last Name: Compton
Location: Kemptville

Re: Stromberg OF choke question

Post by Bruce Compton » Sun Feb 24, 2019 11:54 pm

Mark : Do like Michael says and use the lower lever on the choke control. It's almost the same as the arm on an NH but the Stromberg has no return spring built into the mechanism. If everything is totally free, the choke will usually open by gravity, but I attach a light spring to pull it open. The choke arm has nothing to do with adjusting the mixture for driving (like the mixture control on all the original T carbs). Once the two adjustable jets are set, no more adjustments are required except for maybe idle speed occasionally. Cheers : Bruce

User avatar

Ruxstel24
Posts: 1747
Joined: Sun Jan 06, 2019 11:25 am
First Name: Dave
Last Name: Hanlon
Location: NE Ohio
MTFCA Number: 50191
Board Member Since: 2018

Re: Stromberg OF choke question

Post by Ruxstel24 » Mon Feb 25, 2019 4:34 am

I added a return spring to mine also and used the original choke rod.
The Stromberg likes a little choke till it runs for 20-30 seconds. I also put a piece of vacuum line around the choke rod where it goes through the firewall to hold it in place.


Farmer J
Posts: 27
Joined: Sun Jan 06, 2019 3:20 pm
First Name: Jerry
Last Name: Kramer
Location: Richmond, IN

Re: Stromberg OF choke question

Post by Farmer J » Mon Feb 25, 2019 6:01 pm

Mark, Could you go over the preliminary adjustments you talk about. I am thinking of putting mine on my RPU and don’t know where to begin with the adjustments.


Topic author
Mark Osterman
Posts: 650
Joined: Mon Jan 07, 2019 10:18 pm
First Name: Mark
Last Name: Osterman
Location: Rochester, NY

Re: Stromberg OF choke question

Post by Mark Osterman » Mon Feb 25, 2019 7:12 pm

Screw the lower slotted knob (idle jet) down till is seats and then open 1 complete turn. Screw the upper slotted knob (high speed jet) till it seats and then open 2 1/2 turns. This is an initial setting for starting. Then you work on fine tuning ... that’s where I am right now and haven’t really “arrived.” It’s important to remember that screwing the slotted knobs in gives a rich mixture ... turning them out leans out the mixtures.

User avatar

kelly mt
Posts: 89
Joined: Sun Jan 06, 2019 2:55 pm
First Name: Pat
Last Name: Kelly
Location: Noxon MT

Re: Stromberg OF choke question

Post by kelly mt » Mon Feb 25, 2019 7:17 pm

This is my set up. I used a choke cable with a knob that looks like the original choke control. Also used a spring. Works good.
IMG_1314crop.jpg

User avatar

Mark Gregush
Posts: 1662
Joined: Sat Jan 05, 2019 1:57 pm
First Name: Mark
Last Name: Gregush
Location: Portland Or
Board Member Since: 1999

Re: Stromberg OF choke question

Post by Mark Gregush » Mon Feb 25, 2019 7:28 pm

Or open the link I posted to the instruction booklet.
I know the voices aren't real but damn they have some good ideas! :roll:

1921 Huckster
1925 Cut down pickup

User avatar

Ruxstel24
Posts: 1747
Joined: Sun Jan 06, 2019 11:25 am
First Name: Dave
Last Name: Hanlon
Location: NE Ohio
MTFCA Number: 50191
Board Member Since: 2018

Re: Stromberg OF choke question

Post by Ruxstel24 » Mon Feb 25, 2019 7:59 pm

Mark Osterman wrote:
Mon Feb 25, 2019 7:12 pm
Screw the lower slotted knob (idle jet) down till is seats and then open 1 complete turn. Screw the upper slotted knob (high speed jet) till it seats and then open 2 1/2 turns. This is an initial setting for starting. Then you work on fine tuning ... that’s where I am right now and haven’t really “arrived.” It’s important to remember that screwing the slotted knobs in gives a rich mixture ... turning them out leans out the mixtures.
Mark, that statement is true on the low speed adjustment only. The high speed adjustment, out (counter clockwise) is rich...

Respectfully Dave


Topic author
Mark Osterman
Posts: 650
Joined: Mon Jan 07, 2019 10:18 pm
First Name: Mark
Last Name: Osterman
Location: Rochester, NY

Re: Stromberg OF choke question

Post by Mark Osterman » Mon Feb 25, 2019 10:28 pm

Whoops .... Thanks Dave.


StanHowe
Posts: 500
Joined: Mon Jan 07, 2019 5:42 pm
First Name: Stan
Last Name: Howe
Location: Helena, MT
MTFCA Number: 19133
Board Member Since: 1999

Re: Stromberg OF choke question

Post by StanHowe » Mon Feb 25, 2019 10:55 pm

Mark, did you not get a book with yours?
The idle feed is a fixed .028 jet, the adjustment knob is an air bleed. Turning ccw adds more air. The high speed adjustment is ccw for more fuel.


Topic author
Mark Osterman
Posts: 650
Joined: Mon Jan 07, 2019 10:18 pm
First Name: Mark
Last Name: Osterman
Location: Rochester, NY

Re: Stromberg OF choke question

Post by Mark Osterman » Tue Feb 26, 2019 6:40 pm

Hey Stan,

Don’t ask me questions ... get back to that U &J rebuild of mine. LOL .. Just kidding. Here’s the thing, I actually have a vintage copy of the Stromberg OF booklet but for the life of me I can’t find the damned thing. So, I’ll keep digging. I like to do my own adjustments so that I understand what’s up. So even though you sent it to me properly adjusted I did the initial adjustments again as I posted .. and the carburetor came to life easily. The idle was actually pretty good. I do need to spend some more time on the high speed adjustments but my garage is unheated and it’s really cold here right now in upstate New York. Anxious for a 50 degree day sometime soon. I want to feel the difference that this OF can do.

Yes, that was a mistake what I posted about the lean / rich adjustments of the two slotted screws. A dyslexic moment. Thanks to those who pointed that out.

Post Reply Previous topicNext topic