pilot screw 0-ring blues

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May 4, 2006
morning, evening to all across the water.....i am having trouble with my pilot screw 0-rings being to big and slipping off their groove and not going in right. i had this problem with the re-build kit rings and ordered more from a differnt source (all britts) i have managed but don't like the way they went in. do they need some type of lube? thanks, jerome oh yeah, i have amal 932's and ordered with part # in my parts manual.
pilot screw O rings

I also found that these O rings tend to grab and pluck slightly even though the carbs were scrupulously clean etc. However, the merest touch with a faintly oily finger and the screws and O rings entered the carbs without any problems.
The O rings are probably nitrile rubber and unlikely to be adversely affected whatever oil you use.
I think that the O rings are Viton and they are much cheaper from a bearing supplier. Take your screw along to make sure you get a good fit in the groove.

I always put a smear of silicone gasket goo on the rings. It acts as a lubricant during assembly and helps ensure that no air finds it's way past to cause erratic running. Silicone is not petrol resistant but it shouldn't come into contact with any on the air and tickover adjusters.

An air leak here makes it impossible to set an even tickover.
You can smear a bit of soapy water on the O rings to help fit them or for long term lubrication you can buy some rubber grease.
thanks again mates! i will try the lube method. sychronizing the thottle cables has seemed to really help with smoother accelleration. i still suspect some leakage from the o-rings for the idle(tickover) is still a bit eratic. will remedy that tomorrow. the new needles and jets have made a big difference in the richness, in fact i may be abit lean. will test again when i am sure no air leaks. cheers, jerome
pilot jet O rings

Erratic idle can also be caused by worn slides. They tend to wear most in the small throttle opening positions, which affect idle and just off idle postions.
Test them by opening the throttle by 1/8 to 1/4 and see how much forward and backward movement is evident. You can get chrome plated slides, which wear more slowly. The carb bodies also wear but are more expensive to fix.
It is also worth removing the carbs and checking that the flange faces between carbs and manifolds are flat. They tend to bow with age and cause a potential source of air leakage, made somewhat inconsistent by engine vibration. Patient filing will usually get these back to true.
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