Thread: Stromberg CD carby - mixture adjustment screw??

Where the oil damper is... if you remove that there is a special tool that you put down there that allows you to adjust the mixture. Its a shame you're in Perth as I have one downstairs

bugger I was hoping I wouldn't have to go hunting for that "Special Tool".
Oh well, is this "Special Tool" expensive?
Are they readily available of order part only?

There are two LR dealers near me I'll try them both tomorrow.

Steve

Howdy: In the absence of the LR tool, (Which I doubt you'll be able to find from the LR stealers ) a long nose allen key will suffice. However, to use this, you have to take the needle /float assembly out. The LR tool holds the float from twisting and damaging the rubber diaphram, whilst the allen key raises or lowers the needle assembly. Be carefull with the needle - the screw in the side of the float which holds the needle in the adjustable assembly can break if you use the wrong size screwdriver, or previous owners can permenantly fix it in position by soldering. It may be that your mixture is off because of excessive blow by being sucked up into the carb from the PCV system-go for a heavier oil. Or the carb is fouled up in the side galleries by a build up of gunk - take the PCV, and aircleaner off and give a good dose of carby cleaner whilst revving the engine a little. If that still dosen't make a difference, try to balance the two carbs - the idle adjustment near the link on the drivers side carb, and at the front of the passenger side carb. Make sure the link is the proper length.

Langy

Originally posted by langy
Howdy: In the absence of the LR tool, (Which I doubt you'll be able to find from the LR stealers ) a long nose allen key will suffice. However, to use this, you have to take the needle /float assembly out. The LR tool holds the float from twisting and damaging the rubber diaphram, whilst the allen key raises or lowers the needle assembly. Be carefull with the needle - the screw in the side of the float which holds the needle in the adjustable assembly can break if you use the wrong size screwdriver, or previous owners can permenantly fix it in position by soldering. It may be that your mixture is off because of excessive blow by being sucked up into the carb from the PCV system-go for a heavier oil. Or the carb is fouled up in the side galleries by a build up of gunk - take the PCV, and aircleaner off and give a good dose of carby cleaner whilst revving the engine a little. If that still dosen't make a difference, try to balance the two carbs - the idle adjustment near the link on the drivers side carb, and at the front of the passenger side carb. Make sure the link is the proper length.

Langy

Good post... spot on. One thing to add though... I've found that the adjustment on these things isn't really very effective. It's really only a minor adjustment. It is possible that the needles are already all the way up (full rich), or even if they are currently ful lean, that winding them all the way up may not make enough difference for you. I guess what I'm trying to say is that you may find you have to order new needles if you wish to make large adjustments.

As langy said though, check the basics before doing this... is that the float height is right and that there are no tears in the diaphragm. I have a tool called a "colour tune" that you put in the sparplug hole in place of the spark plug. It enables you to see the colour of the flame and make adjustments accordingly. It's very good. Maybe you can borrow one from somewhere ?

Hi

Thanks for the advice glad to know I can use an allen key in lew of this special tool.

I'll check the other things tha you mentioned, I've never messed with the balance though , should be fun


thanks
Steve

Remove twins and fit single carb - no more probs !

Yer, I have thought about that loads of times, it just comes down to cash and convenience.

I could replace it with a used single carb but then there is no guarantee that the used cab will be in good order.

If I could get a good one and fit it myself, I think I would need to change the manifold as well? Then it would be a good Idea.

I did hear, (somewhere?) that single carbs tend to have a hard time on very steep inclines uphill, or it that a load of cr@p, also would a single carb deliver as much petrol and twins ie would the engine suffer a power loss loosing one carb?

Don't worry about balancing them... it's easy. Just get a couple of feet of plastic tube. Start engine, and then place one end of tube in ear. Place other end of tube right near carby intake. If one is louder than the other adjust accordingly... SIMPLE. Do not let any jokers apply full throttle while you're doing this delicate operation or you may need a change of underwear 8O