Rochester idle mixture screws?

[berke99]

I have an 88 Lund Tyee 5.5 with 3.0 ltr. engine with a rochester 2bbl. carb. The rear idle mixture screw has no effect on the engine while trying to adjust the carb. Is there an easy fix for this or does it need a rebuild? Thanks for any tips and ideas.

[boatfixer]

You can try removing the mixture screw and spray carb cleaner in hope that the blockage is there, but more than likely you will need to disassemble and rebuild the carb, it's probably deeper into the passages.

Just out of curiosity, what is the carb tag number?

[berke99]

The only number that I can find on the carb is 61714227. Is that the number you were asking about? Out of curiousity why were you wondering? Thanks- Greg.

[boatfixer]

Mercruiser used 2 carburators in that time era. The rochester which has 2 idle mixture screws and the Mercarb, which is nearly identical, but has only 1 idle mixture screw. Almost every 4 cylinder that I've seen with 3.0 as the model, as opposed to 140 hp as the model, has had a Mercarb on it. After doing a little digging I found both were used on the 181 cubic inch engine in that time. I asked mostly for future reference. Thanks