Club 80-90 Forums

Hi, i have my engine out at the moment and have just noticed that if you manually operate the carbs, the butterfly at the top only opens about half way, its the same on both sides, is this normal operation, i would of thought that they would open to almost a vertical position?

I have no real symptoms as such, apart from no real power up hill. Its an 81 with a CJ engine.

Thanks.

When you say 'manually operate' do you mean you've powered them from a battery? The only way to get the chokes to open fully is to apply 12V to the the choke* and wait a while, (time dependent on temperature), until the choke operating coil is sufficiently hot, only then will the choke plate be vertical.

When you open the throttle fully but the chokes are still cold, the choke plate will open part way, as you've found. This is due the linkage from the choke pushing the butterfly open slightly in order to prevent excessive richness at larger throttle openings when the engine is cold, similarly there is a vacuum operated choke override that backs the choke off when you lift off when cold, this is to prevent excessive richness at high vacuum with the choke on.

*Positive to the spade on the choke, negative to the body of the carb/choke unit.

Thanks, i was just operating the throttle - DIY mechanic

As i said no major symptoms, so fingers crossed they are all ok then?