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Hot Rods Need help adjusting my stromberg

Discussion in 'The Hokey Ass Message Board' started by jjjmm56, Mar 26, 2019.

  1. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 464

    28 Ford PU
    Member
    from Upstate NY

    Secondary throttle plates are a bunch of crap from the guy in Vero, FL. Stock plate were designed many years ago to work in these carbs by engineers not some beach bum.

    Make sure the detent/1/2 moons are facing down. The edges are angled and must be facing down to fit the bore.


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  2. jjjmm56
    Joined: Feb 7, 2009
    Posts: 531

    jjjmm56
    Member
    from FL.

    I want to thank everyone for the help I’ve learned plenty. I’m going to pul the carbs off tomorrow and check the plates. I never thought they’d be different. When I rebuilt I pulled all the tubes and soaked them a ultrasonic cleaner and high pressure thru all the passages. I got all my parts from max. I also replaced shafts and bushings.


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  3. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 464

    28 Ford PU
    Member
    from Upstate NY

    If you got your parts from Max I suggest you call him with your concerns. Max is the Stromberg wizard plus a nice guy if he can’t help nobody can.


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  4. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,681

    Bruce Lancaster
    Member Emeritus

    "you should be making adjustments with air cleaners on, as they will cause a richer mixture when installed"
    This worries me! A good answer is going to be hard to find.
    If aircleaners affect mixture significantly, especially at idle when air flow is small, you obviously have air cleaners that restrict air flow. You will have this I think with all the hotrod small cleaners, which seem about right for a lawnmower...
    Getting mixture right with jet changes is probably not going to correct things in all the different metering areas forom idle up to the higher RPMS when gas is going through the jets, either. The idle and off-idle circuits remain important through about 2,000.
    The solution is not clear...basically you have a choice between dysfunctional but pretty air cleaners and huge, ugly 1960's-1970's Detroit filters that will show NO restriction on most engines but look like crap...
    In the meantime, do all your tuning with NO airclener...you are not going to wreck your engine quickly that way. THEN put on the cleaners, and if they change anything you need to do some work.
    TWO big problems...change when your cleaners go on means you have AIRFLOW RESTRICTION. Free airflow is where power comes from and there is no way around that. How well do you run with a cork in a nostril?
    If you don't care about losing power...You ARE a hotrodder, right?...there is a WORSE problem. Restriction is the same thing as pulling out your choke knob...you LOWER air flow and power while RAISING flow of gasoline. An engine running this way can wear out its piston rings in a few hundred miles!
    I too like the look of three absurdly tiny chrome cleaners...
    Probably a real solution would be a home made oval plate with airhorn connections from three discarded aftermarket cleaners attached. There are good charts of filter shapes and dimensions in catalogs online...you could likely start with a 406 Ford triple filter element!

    Throttle plates: As noted above, the plates must be able to fit their bores, and it must be possible to fully or greatly block the bores depending on whether progressive or not. If you can get the thing running well without progressive, meaning better mixture control overall, you have to be able to achieve very small gaps.



    S0...remove the throttle bodies, close throttle at lever, and look through the bores with good light. You will most likely see lots of light!
    Loosen the two screws through each blade on all of them...looen as little as possible to allow them to move. Shake, jiggle, poke and, and swear at the things until gaps are closed...if no go, start swapping between carbs as noted by people above. Tighten firmly when you finally get somewhere!

    A 303, with displacement nearly at the outer limits for a useable flathead, should in my opinion be able to pull a full-time triple and so have full normal mixture control. But, whatever, put the bases on your engine fully close, hook a spring on each so nothing tries to open while you are working, and go to it.
    With aftermarket throttle arms on the left side as on nearly all setups, install said arms at typically 45 degrees measured from engine deck. Assemble and adjust your linkage so the attachments that will connect to your 3 arms
    are the same distance apart as your 3 carbs' throttle shafts.
    Linkage should be able to drop into place with the carbs shut. If full service, put it on with all three held closed. If progressive...adjust center carb to guessstimated idle setting. From here, adjust for idle with engine idling...this would be TINY openings all around as a starting place.
     
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  5. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    that 303 should be running all 3 three carbs straight linkage. no reason to run it progressive. and please don't block off the outer carbs. no way 150cfm is enough for that motor. check the plates if you have to, but I would make sure the the jets are the correct size, the float levels are correct and put the choke plates back in. stromberg designed the venture to use them to direct the air properly.

    start at 1.5 turns on all three carbs idle mixture screws.
    setup the intake with no linkage attached and back off all the idle stop screws until the they don't touch. then screw them in until they just make contact. fire up the motor and bump them a 1/4 turn at a time or so until the idle is about where you want it. pull out the unisyn and check all the carbs. adjust the idle stops as needed. when they are all the same hook up the linkage and verify they are still the same.

    at this point you can start playing with the idle mixture screws again. you will probably end up with them lower than 1.5 turns.
     
  6. jjjmm56
    Joined: Feb 7, 2009
    Posts: 531

    jjjmm56
    Member
    from FL.

    I’m going o remove the two outer carbs and block the manifold and fuel lines. I need to put a few miles on the engine because I don’t want to keep fiddling with the carbs without having the motor broken in more. I’m going to drill four 1” holes in the air cleaner cover for better flow for now. I want to see if I can get the mixture right on one carb first. This engine only had a 2 barrel carb it start with. I’m going to get with Max on Monday and get his input. I’ll order whatever I need at that point. I also ordered a uni - syn from speedway. As I stated earlier the engine starts right up and no problem idling. I’ve run it for about 1/2 to 3/4 of an hour at different rpms to break in the he cam already.


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  7. prpmmp
    Joined: Dec 12, 2011
    Posts: 1,129

    prpmmp
    Member

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