B&S carb mixture screw.

Hey guys, I am working on getting a 18hp opposed twin briggs (horizontal shaft) running. I took off the carb, disassembled it, cleaned it and during the process of reassembling it I realized I had no idea how many turns I should put the mixture screw in. I took it apart without counting the turns, and now I'm dead in the water. Does anybody know the stock settings? I have no idea what the model number is, I couldn't find one. Is there any way to find out? Any help is appreciated. Thanks.

put them all the way in, then back them back out a turn and a half.... start there and adjust as needed

x2 on lawren. generally, if that wont start it, i back it out 1/4 turn at a time until it starts, and go from there

Regarding the model number- yes and no. The Type and Code numbers are pretty much anybody's guess, but the actual model number is sweet and easy. The format will resemble 421707. First two digits are displacement in cubic inches, the rest describe engine features. Have a look here- http://www.briggsandstratton.com/us/en/~/media/Frequently%20Asked%20Questions/Engine/Numerical%20Designation%20System.pdf

So in my example above (421707) the engine would be a 42 cubic inch Thus, 18hp or variant of same), Vertical crank, Plain bearing, splash lube, electric start with alternator.

Now, i believe your TYPE would be above 1100, because i see by your intake manifold that you have a second generation twin, but an earlier second gen because of the adjustable high speed needle on the carb.

What the others said, but generally its 2 whole turns to run, 2 1/2 is running good but, some times 3 whole turns works better, it all depends on your elevation and climate.
This is spaciicly on the fuel mixture screw.

Thanks for the advice guys, I hope I didn't cock myself over because the thing has been sitting for years, but it ran when put away so there is hope.

nah, it'll run, just a matter of caressing it right. give it proper fuel, give it proper air, and it will run

Good to hear.

The book calls for 2 1/2 turns out from all the way in. When your screwing it in be sure to NOT forcefully screw it. Do it slowly until it gently stops.

Start at 2 1/2 turns out run it to operating temp ( 10 minutes ) then let it idle and adjust it slowly outwards and if the RPM's drop, go inwards until you find the spot where it idles the highest then once you find it, back it out 1/4 turn so its not too lean.

The idle mixture isn't as critical as the main jet mixture. One stupid thing about these carbs is that it uses a set main jet. Meaning it cant be adjusted. So depending your altitude it might not even run right.

Hope all goes well!   

Good news, I got it running, 2 turns out seemed to work fen

beg my pard, I meant to say fine