Technical Throttle stop screw keeps working it’s way out.

[Sbf500]

Hi everyone, as per the title really. Recently my throttle stop screw keeps working its way out. Recently on a long run it worked its way completely out. Luckily I had a spare in another carb body. However today I lost the second one which is always fun when you pull to a stop and the car cuts out as the idle is so low.

Both of them had the springs so I was surprised it happened again. I haven’t noticed any vibration coming from the engine, well no more than normal, so not sure exactly what is causing it. Main question though is what size is the screw and anyone know what spring I should get as I couldn’t find any on the web in any of the usual places.

Thanks
Al

 

[Toshi 975]

I can tell you that the screw size is M4 x 16. Is it possible that the thread in the carb is worn?

 

[Sbf500]

I can tell you that the screw size is M4 x 16. Is it possible that the thread in the carb is worn?

Thanks Toshi, that is definitely a possibility, seems to be plenty of extra room around the hole so and increase in size shouldn’t be to much of a problem if it is.

 

[Toshi 975]

Thanks Toshi, that is definitely a possibility, seems to be plenty of extra room around the hole so and increase in size shouldn’t be to much of a problem if it is.

If it is a standard 26IMB carb you are running I might have a spare arm in my spares box. Also have M4 and M5 hex head screws.