1997 f50 carb adjustment sync

[Knox1988]

I have a 1997 F50 and im trying to sync all 4 carbs and I have the top three of the vacuum guages balanced at 20inches but I cant figure out how to adjust the bottom carb with out changing the idle.

 

[jeffersondodson561]

Re: 1997 f50 carb adjustment sync

I am looking at the F50 service manual for that year. What you need to do is keep the bottom carb, #4's idle at 1000 rpms during the whole test. #3 carb's vacuum should be (-).4inhg from #4 carbs vacuum, #2 carb's vacuum should be (-).8 from the #4 carbs vacuum and #1 carb's vacuum should be (-)1.2 from #4 carbs vacuum. Once this is obtained, then reduce #4 idle down to 750+/- 50 rpms in gear.