rochester 2 barrel adjustment

[joseph1980]

Hi guys,

i recently got a rochester 2 barrel to replace the mercarb that was on my 2000 reinell 3.0. are the tuning/adjustment procedures any different than they were with the mercarb?

 

[Juniinc]

Re: rochester 2 barrel adjustment

I think Mercarb has only one idle mixture screw.
Rochester Carb has two idle mixture screws at least some older model did,,,

 

[joseph1980]

Re: rochester 2 barrel adjustment

yea it has two, just wondering how to adjust it correctly

 

[Juniinc]

Re: rochester 2 barrel adjustment

2 screws must turn in same sequence.
I usually do 1 full turn each time.
when its all the way in, take it easy,,, U do not want to damage em.

 

[cr2k]

Re: rochester 2 barrel adjustment

Yes it tunes basically the same, but one at a time and not more than a 1/2 turn at a time and be sure to balance them after you get it idling smooth.

Balancing= if one screw is 2.5 turns out and the other is 1.5 turns see if it will run with both at 2. Just take it a little slower and listen for changes closer.
Not all carbs will be correct with both needles at exactly the same settings due to slight differences in needles and seats. You will have to adjust your idle speed a few times along the way too. Then you want to get a good re-start.
should re-start with no throttle and then idle down to right idle speed.

 

[joseph1980]

Re: rochester 2 barrel adjustment

so in other words do one needle until it runs rich, then lean and find the spot in between. and then perform the same procedure on the other needle?

 

[cr2k]

Re: rochester 2 barrel adjustment

Kinda like that. first start by turning one in all the way GENTLY so as not to damage the needle or the seat. If you end up with the engine still idling and BOTH needles all the way in you need to rebuild the carb.