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Recondition cold start valve

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Just in case anybody is facing the same problem.

I realised my cold start valve was stuck after not being used in 35 years... this is what I did:


measured the resistance, was around 5 Ohm. Tried pulsing with a lab power source at 9V (current limited to 0.5A) -> nothing


increased current to 1.5A max --> nothing


Ultrasonic treatment (Bandelin high power source) immersed in 2-Propanol  (Iso)  for 5 minutes  -> nothing


injected ISO straight through the nozzle end into the mechanism (around 80µl) and used US again -> nothing (but might have helped the next step. be VERY careful not to touch the needle. If you have, a small transparent Eppendorf tip works great with a 10µl syringe ;)  )


then moved to the lab source and tried braking in free. It cracked open at 16V  1.5A and is now working perfectly at 9V 0.5A


it is paramount to only TAP it very shortly above 12V or so, at 16V 1.5A it was producing sparks but broke free at the first tap. DO NOT attatch both wires and increase the voltage, go in 1v increments and tap. A lab source is great, especially if it shows when you max out your current.


next step will be  syringe-feed carb cleaner while pulsing the valve submersed in more carb cleaner.



total work time, around 30 minutes if you cut out the first try. (Its blocked and ISO won´t reach the place its needed to be...)

Edited by Villeman

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