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OER/Weber 45 DCOE clone

Last post 04-09-2010, 1:20 PM by lcjutila. 14 replies.
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  •  10-18-2006, 7:20 PM 1381

    OER/Weber 45 DCOE clone

    Having a problem on starting the card when cold. There is no choke, but it takes numerous pumps(25) of the throttle to get it started.

    It feels like there's no gas getting to the carb. Funny, car runs good once it starts. Could this have something to do with the float level?

    This carb has an external adjustment for the float. I'm assuming turning clockwise would raise, and counter clockwise would lower?

    Supposedly the float should be set at 29mm or 1.14 inches. Looks like I may have to remove top cover. I'll report back with my findings.


    Cheers, N 


  •  10-19-2006, 10:49 AM 1417 in reply to 1381

    Re: OER/Weber 45 DCOE clone


    Tell me more about this carb. Is it a Weber or not? Weber DCOE carburetters have no external adjustment for the float. Also, a cold start valve device can be added to most DCOEs. give me more info about this carburetter!!

    From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon
  •  10-19-2006, 11:01 AM 1419 in reply to 1417

    Re: OER/Weber 45 DCOE clone

    It's supposedly the old SK carburetor made by OER out of Japan. It takes all weber jetting except for the accelerator pump jets. It has an external float mechanism to adjust the float. You can also adjust the duration of accelerator pump jets. Here's some more information:


    I would have bought a Weber, but at the time they were hard to come by and $$. Looks like I'll be taking the cover of it this afternoon. I'll repor back on my findings.



  •  10-19-2006, 1:34 PM 1429 in reply to 1381

    Re: OER/Weber 45 DCOE clone


    How does the carb work on hard acceleration? Does it fall flat on it's face?

    I'm wondering if the pump circuit may be plugged. A couple of pumps should be enough fuel to start, not 25. I'm not that familiar with the guts of the SK, but I know it is pretty similar to the DCOE with a pump piston and pump jets. If the piston assembly is damaged or the pump jets clogged starting would be a problem, but also the engine would bog when you try to accelerate.

    I've had similar problems with a DCOE when the pump piston sticks in the pump bore from disuse. The car will accelerate slowly, but if you punch it the engine will almost die.


    Kelvin Dodd
    Global Sourcing Engineer
    Moss Motors, Ltd.
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    Disclaimer: Working on automobiles is inherently dangerous. Moss Motors, Ltd. is not liable for injury or damage due to incorrect installation or use of their products. All products are sold with the understanding that the safe and proper installation and use of the products is the customer’s responsibility. Follow factory workshop manual procedures and instructions, but use current shop safety standards and common sense. Some tasks will require professional advice or services which Moss Motors cannot provide.
  •  10-19-2006, 4:05 PM 1434 in reply to 1429

    Re: OER/Weber 45 DCOE clone

    I've verified the problem. The accelerator pump does not work at all. The car runs ok, but on hard acceleration it will ping. I'm assuming this is due to a lean mixture. This would also explain how you can pump the pedal 25 times and the car still won't start. I do not know what I'm going to do at this point. I may just buy an authentic 45 DCOE. I'm not overly impressed with the OER as you can tell.



  •  10-22-2006, 8:08 AM 1540 in reply to 1434

    Re: OER/Weber 45 DCOE clone

    Here's a look inside one of the (three) Webers on my Healey. 

    I'd think now that you know the pump circuit isn't working, that you could go after it and find out why...

    57 Healey 100/6 BN6L-942
    61 McCulloch R1 go kart
    99 M Roadster (supercharged)
    01 M Roadster
    11 BMW X5 35i
  •  10-22-2006, 9:01 AM 1541 in reply to 1540

    Re: OER/Weber 45 DCOE clone

    I saw these pics on another post somewhere. I emailed one of them to some friends.

     Here's what a happened. The accelerator pump rod broke. The rod has a hook at the bottom which connects to the piston. The hook was broken inside the piston, so the piston would never return. This carburetor is nearly identical to the Weber 45 DCOE, but the OER uses mickey mouse steel for the accelerator rod. It's nowhere near the quality of the weber. My mechanic friend luckily had several old DCOE's lying around his shop. He cut the hook off one and had the welder next door weld it to mine. My car now starts almost immediately and runs like a raped ape. I no longer have pinking and the car really hauls ***. Thanks for everyone's replies.

  •  04-03-2010, 10:22 AM 23291 in reply to 1540

    Re: OER/Weber 45 DCOE clone



    Just seen an old reply of yours after searching for solutions to my Healey 3 45dcoe conversion. First had serious vacum leaks as kit was incomplete and rubbish. Having got that sorted put in new Mallory dual point dist: and basically now runs idle good little on the rich side. On accerlator pumps with car static good but around 3000rpm starts to pop through the carbs. Timing set at 15BTDC on idle. Changed main jets from 145 as supplied to 155's. better but not great. Racked timing to around 35BTDC and will run through 3000rpm fine with just occasional pop. Road test  and will handle low rpms good under load but will ping when stressed under acceleration. Really head scrathing, can you advise, i am in Florida





  •  04-03-2010, 2:38 PM 23295 in reply to 23291

    Re: OER/Weber 45 DCOE clone


    What size main chokes (not the cold start device, Weber refers to the restrictor that determines the smallest diameter of the throat a choke, just as on a shotgun) do you have? they are marked in MM. We find that many of these carbs, especially on triple setups, have way too big a choke installed. Some pop and pink on initial accelleration, or just plain drop dead. The reason is that at low vacuum the velocity of the "signaling" air passing over the jet venturris drops and won't provide good atomization, and sometimes, fuel.

    The thing to remember about Weber DCOEs is that, as on most all Webers, the idle circuit actually makes up not just not the idle fuel delivery, but half to two thirds of the rest of the running range. It occurs to me that your problem might just be during the transition from the idle jet circuit to the main circuit. My thought is that you may have too big an air corector jet, or too small a main jet. Or, it could be a somewhat plugged main circuit. As far as choke diameter goes, I wouldn't venture much bigger than around twenty eight MM. We had a TR6 here that wouldn't run worth a nickel until we installed TWENTY SIX MM chokes. At that point it idled smoothly, and ran like a missle. The more throats you use, the smaller the restriction must be to get an equivalent result in gas velocity. Just something to think on.

    By the way, Haynes puts out a pretty darned good book on Webers, with theory, exploded views, tuning reccomendations, and overhaul procedures.

    Another by the way. It seems to me that you have too much ignition timing for this engine. That's far more likely the cause of the pinking you hear on accelleration. Start with it at absolutely factory stock, then mess with the carburetters. Advance it only as far as not to pink AFTER the fuel problems are solved 


    From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon
  •  04-04-2010, 3:41 PM 23309 in reply to 23295

    Re: OER/Weber 45 DCOE clone


    Condenser/points will also give you that popping through the carbs and I am inclined to that area more than the Webers.

    Around 3,000 rpms is when it changes from idle to main jetting. To find out exactly the crossover rpms, loosen or remove the main jet assembly and accelerate until the engine dies. That is the crossover point. If that coincides with the popping then you could need to adjust your jetting.


  •  04-05-2010, 10:08 AM 23316 in reply to 23309

    Re: OER/Weber 45 DCOE clone


    I like your elegant diagnosis technique but would make an observation. The different fuel systems overlap in operation. There is a short period of transition time where the idle circuit is diminishing and the main circuit is coming on. So I think the crossover rpm may be slightly below where the engine dies.  


  •  04-05-2010, 1:28 PM 23318 in reply to 23316

    Re: OER/Weber 45 DCOE clone

    You are correct, with this method, when it dies is when you are on the high end of the idle circuit. 

    I left the main jets assembly loose one day and just stumbled on that "technique".



  •  04-06-2010, 1:19 PM 23325 in reply to 23295

    Re: OER/Weber 45 DCOE clone

    Thanks for all the replies and interest, it seems a subject that many have had in slightly different circumstances.

    Took the beast for a road test today, backed off timing as i agree way to far advanced fot this motor, probably just ahead of stock setting, pinging not evident, however popping now occurs around 2500. Now the funny bit, cruise at 2500 with slight popping on random carbs, pull choke out fully, goes like stink and remained fully drivable even when slowing down and reaccelerating. I am now leaning, escuse the pun, towards incorrect jetting as idle is smooth even at 600rpm. I am told these webers should have 900 min and timing at 3000rpm 36btdc. The internals are all new and stock with the exception of main jets which i have upped tp 155 already with little effect. Here are the stock settings

    Main Venturi 36

    Aux vent 4.5

    Air corrector 155

    Emul tube F16

    Main Jets 145  now 155

    Idle 55F8

    Pump Jet 45

    Exhaust Valve 40

    Needle 2.0

    Feels like i am getting so close, really appreciate all the advise and will certainly look out for a Haynes manual on my return to the UK.


    As an aside i also run in Florida a 1962 TR4 and a 1962 Silvercloud, best is British!

  •  04-07-2010, 3:51 PM 23339 in reply to 23325

    Re: OER/Weber 45 DCOE clone


    If pulling out the choke solves the problem you are most likely way to lean. In a lean condition you can get  very close to the correct mixture and the car does not respond. When you do go that small bit richer all of a sudden you notice a big difference. This also results in a sudden jump in gas mileage because the engine starts making proper power and burns the fuel more efficiently. Just went through this exercise on my Mustang. It only took a 4% jet size increase to make the big difference. Gas mileage increased 10%.

    By the way, the car was still jetted on  the economy end of the mixture/lean so you could probably go richer still to make more power.


  •  04-09-2010, 1:20 PM 23351 in reply to 23339

    Re: OER/Weber 45 DCOE clone


    The "Book" says:

    Choke Size/Main Venturi= 36

    Auxilliary Venturi= 4.5

    Main Jet = 1.65

    Emulsion Tube= F16

    Air Corrector Jet =1.50

    Idle Jet=0.55F8

    Accelerator Pump Jet=0.45

    Accelerator pump Inlet Valve w/ Exhaust Orifice= closed

     Needle Valve = 2.00

    So you are a little too lean, but very close. If you have unlimited funds it may be worthwhile as per Motorbill to try 32mm or 34mm main venturis. They will make the throttle response snappier and help emulsify the fuel better by increasing the signal to the main booster/auxiliary venturi. You will lose a slight amount of horsepower on the top end but most of us spend very little time with the car red-lined and completely floored and a lot of time at part throttle.  

    Good Luck!