My TR6 is running really rich. So bad it is leaving soot on the back of the car, and it runs really, really under temperature (cool), hardly registering on the temperature gauge, which is a bad thing for engines. I bought the Zenith Stromberg adjusting tool from TRF, and tried to adjust the carbs. Really, really hard to turn the adjuster. A friend suggested that my o rings were old and crusty, causing the problem, and as you will see he was right. I’ve rebuilt SU carbs before, and messed with the temperature compensator on a Stromberg before, but never changed the o rings. the best site I found explaining the procedure is here http://www.vtr.org/maintain/zs-tech-tips.shtml and I found the pictures here helpful as well as the initial setting and tuning info here http://www.buckeyetriumphs.org/technical/Carbs/CarbsII/CarbsII.htm
So I did the following (see better instructions and diagrams on sites above, I’m just documenting the stuff I learned in addition)
- removed the top of the carb, pulled the piston, drained oil.
- turned the adjuster counterclockwise maybe 20 turns. Really hard to turn at first, was concerned I was stripping it. Later I discovered it only needs to be turned about 4 turns and then you are just spinning it, it has come free from the threads, but the retaining clip made of spring steel is still keeping it from falling out
- loosened the retaining screw
- removed the needle and carrier
- turned the piston upside down on a piece of wood
- gently drove the retaining clip and needle adjusting screw out with a piece of 5/16 dia x 10 inch dowel through the center, being careful not to loose the retaining clip
- carefully cut the o ring off the adjusting screw
- oiled the o ring with dashpot oil, installed it, oiled it with dashpot oil again
- put the needle back in, carrier flush with the piston
- tightened the retaining screw, not too tight
- put the adjusting screw back in, and with about 3 and a half turns it stops. Turned it counter clockwise 1 turn from tight for the starting position
- be careful to put the piston back into the carb body in the right orientation, with the two holes in the bottom of the piston towards the intake manifold Also, there is a tab on the diaphragm that must align correctly with the slot in the piston if you removed the diaphragm from the piston. I didn’t.
- Be careful that the diaphragm fits in the groove on the carb body, that you don’t damage it by tightening it down not in the groove. I started to do this but caught it in time.
- reassembled the rest, and it started right up.
Tomorrow I’ll mess with the mixture. For now I am just happy that it adjusts easily. Interestingly enough, I was not losing dashpot oil, which is a normal symptom of messed up o rings. Just really hard to turn the adjustment screw