I have my twin Stroms back on, after a rebuild, starts ok, seem to be ideling at 3000 rpm, so how do I get that idel screw down and how do I snycro the cargs ??? Any quick tips ?
First two things I would check are that the butterflies (throttle plates) are closing at idle and that neither carb piston is hanging up. These are both simple visual checks you can make looking down the throats with the plenum removed. You can check both with the engine off, maybe use a bamboo skewer or chop stick to lift the piston and watch it drop. While it is lifted look at the butterfly and see if it is fully closed.
John
As simple as these carbs are there are no quick tips. I say simple because even I can adjust them. Idle is set by adjusting throttle stop screw on each carb. This screw just limits linkage movement, no magic here just a stop screw. As Geo stated pistons need to travel equally and drop down all the way. What parts were replaced in “rebuild”? Did you or a pro do rebuild?
To sync carbs you need an air flow gauge (uni-syn) or a rubber hose with a good ear to detect equal air flow. Adjustments are made at linkage clamps between carbs. Long learning curve if you have not done this before. There are just a few adjustments on these carbs. Needle and float height the major ones, and temp comp. and bypass valve. You need a repair manual to refer to.
Glenn
Thanks have the air gauge tool carb’s rebuilt by a pro installed by me, ill give it go…cheers!
John,
Hope this helps…
How new is the engine? If it’s not new start by closing the air bleed screws located on the RH side of each carb. The fuel temp compensator wont be in use during start and warm up so assuming whoever put the carbs back together knew what they were doing, they should be ok.
First, just disconnect the link that joins the throttle shafts to the pedal linkage. You wont be needing it for setting the carbs up and you can reinstall it when that’s done.
Next, loosen the coupling that joins the two carbs together so that each throttle can move independently of the other…this will mean the pedal will only work on one carb but you WONT want to use the pedal for anything right now.
Next, loosen each of the slow running screws until there’s a gap between the bottom of each screw and the throttle lever. Then wind down each screw separately until they JUST touch said lever and then give each of them one full turn.
Next, if not done already, remove the air plenum so you can see down the throat of each carb.
Next check for free movement of each piston by inserting a long screwdriver and with steady pressure, move the piston up to it’s full lift. You should feel a steady but firm resistance when doing this for each carb. Then let it drop under it’s own weight and it should slowly descend and you should hear a slight click as it bottoms out. If you feel almost zero resistance moving the piston(s) up then you have no oil in the dashpot. Remove the damper and lift the piston to the top so you can see the chamber where the oil goes and using engine oil, fill to 1/4" below the top of the chamber. When that’s done, let the piston go and then reinstall the damper.
So you should now have…throttles disconnected from the pedal…throttle shafts disconnected from each other…throttles set just off fully closed…pistons with the right amount of oil and pistons rising and falling as they should. If any of this is NOT the case then go back and fix that before continuing.
Assuming the aforementioned is all OK, operate the chokes and start the car. Allow the car to get warm enough to run without chokes. Using the air guage check each carb and carefully note where on the guage each carb is reading. Using the idle stop screws on each carb adjust one or both such that each carb reads exactly the same. The aforementioned should be done with the RPM around 750. Then STOP the car.
Next, carefully tighten the coupling between the carbs being careful not to move either of the shafts. You should now have both carbs in sync as far as airflow goes.
If you have the original standard system, that does NOT have the adjustable jets, you’re pretty much done and all there is left to do is reset the pedal linkage to the carbs.
I think that’s it, apologies if I missed anything but feel free to ask questions.
Good luck!
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Thanks almost done, much appreciated info, what’s the standard idle for the E 10-1200 ? rpm
There should be a label on your air cleaner. For a 1970 it should be like this:
-David
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As David said but if you don’t have a label you could probably use 750rpm…might even be 800. Is your car an auto?
Les,
When you say “start by closing the air bleed screws on the RH side of each carb…” is that the “idle trimming screw” you are referring to? and do the screws remain closed after set up?
4 speed manual
I set the idle a wee bit higher than spec. Maybe it’s due to modern fuel or maybe something else but that’s where things seem happiest.
750 should do it. How’s the car running now?
Purring like a big cat should, thanks all… for the great info guys., the blower gaguge tool is the key. Im not clear on the lean/rich settings, seems ok now, what are the signs of too rich or too lean ??