All-Terrain Lawn Tractor Forum
Would you like to react to this message? Create an account in a few clicks or log in to continue.

All-Terrain Lawn Tractor Forum

Like riding lawn tractors through mud, woods, rocks, and snow? Then this is the place for you! Share your ideas, Post your projects and more!
 
PortalHomeSite RulesEventsFAQSearchRegisterLog inBuild-Off

 

 B&S carb mixture screw.

Go down 
+2
Lawren Wimberly
TokyoDrift99
6 posters
AuthorMessage
TokyoDrift99
Member
TokyoDrift99
Member


Age : 24
Join date : 2014-03-28
Points : 3990
Posts : 111
Location : Vermont

B&S carb mixture screw. Empty
PostSubject: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 3rd 2014, 4:12 pm

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.
B&S carb mixture screw. Ul6Jai0
Back to top Go down
Lawren Wimberly
Established Member
Lawren Wimberly
Established Member

500+ Posts
500+ Posts
2014 Build-Off Entrant
2014 Build-Off Entrant

Age : 57
Join date : 2013-12-21
Points : 4761
Posts : 744
Location : Salem Illinois

B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 3rd 2014, 4:22 pm

put them all the way in, then back them back out a turn and a half.... start there and adjust as needed
Back to top Go down
willis923
Veteran Member
willis923
Veteran Member

1000+ Posts
1000+ Posts!

Age : 28
Join date : 2013-04-10
Points : 5717
Posts : 1408
Location : Galway NY

B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 3rd 2014, 5:53 pm

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
Back to top Go down
Doc Sprocket
Site VIP
Doc Sprocket
Site VIP

2500+ Posts
2500+ Posts!
2018 Build-Off Entrant
2018 Build-Off Entrant
2021 Winner of Winners
2021 Winner of Winners
1st Place Build-Off 2016
1st Place Build-Off Winner 2016

Age : 51
Join date : 2013-04-21
Points : 7274
Posts : 2914
Location : Ontario Canada

B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 3rd 2014, 6:54 pm

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.
Back to top Go down
Ariens YT11
Established Member
Ariens YT11
Established Member

500+ Posts
500+ Posts
2014 Build-Off Entrant
2014 Build-Off Entrant
2015 Build-Off Entrant
2015 Build-Off Entrant

Age : 27
Join date : 2012-10-31
Points : 5120
Posts : 745
Location : The Wyo-Braska Panhandle

B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 3rd 2014, 6:57 pm

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.
Back to top Go down
TokyoDrift99
Member
TokyoDrift99
Member


Age : 24
Join date : 2014-03-28
Points : 3990
Posts : 111
Location : Vermont

B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 4th 2014, 12:00 am

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.
Back to top Go down
willis923
Veteran Member
willis923
Veteran Member

1000+ Posts
1000+ Posts!

Age : 28
Join date : 2013-04-10
Points : 5717
Posts : 1408
Location : Galway NY

B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 4th 2014, 8:50 am

nah, it'll run, just a matter of caressing it right. give it proper fuel, give it proper air, and it will run
Back to top Go down
TokyoDrift99
Member
TokyoDrift99
Member


Age : 24
Join date : 2014-03-28
Points : 3990
Posts : 111
Location : Vermont

B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 4th 2014, 3:42 pm

Good to hear.
Back to top Go down
the54
Member
the54
Member


Age : 30
Join date : 2014-01-12
Points : 3982
Posts : 51
Location : Ontario Canada

B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 4th 2014, 9:39 pm

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!  Very Happy 
Back to top Go down
TokyoDrift99
Member
TokyoDrift99
Member


Age : 24
Join date : 2014-03-28
Points : 3990
Posts : 111
Location : Vermont

B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 11th 2014, 9:39 am

Good news, I got it running, 2 turns out seemed to work fen
Back to top Go down
TokyoDrift99
Member
TokyoDrift99
Member


Age : 24
Join date : 2014-03-28
Points : 3990
Posts : 111
Location : Vermont

B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitimeApril 11th 2014, 9:40 am

beg my pard, I meant to say fine
Back to top Go down
Sponsored content





B&S carb mixture screw. Empty
PostSubject: Re: B&S carb mixture screw.   B&S carb mixture screw. Icon_minitime

Back to top Go down
 
B&S carb mixture screw.
Back to top 
Page 1 of 1
 Similar topics
-
» Briggs 12.5 I/C Carb Mixture Screw
» CARB KIT HELP !!!
» Tecumseh hh100 carb
» Help! opened screw on transmission
» Getting rid of a carb solenoid.

Permissions in this forum:You cannot reply to topics in this forum
All-Terrain Lawn Tractor Forum :: Technical Forum :: Engine Tech :: Briggs and Stratton-
Jump to: