Carb adjustment

[Winkster 12]

Hi folks;

Recently got the answer from you guys and replaced condenser and spark plug. 1977 C120 12hp Kohler.

Started right up but began backfiring after awhile..  Wet long grass and some hills.  I'm thinking carb adjustment

but unsure how many turns if I screw both all the way in.  Thanks yet again.

Winkster

[Daddy Don 893]

I had the same problem with mine thought it was the carb did what your doing and it did not fix the problem. Replace the spark plug and it took car of the problem. Hope this might help you out.  

[Ed Kennell 35,867]

9 hours ago, Winkster said:

 

but unsure how many turns if I screw both all the way in.

If you back them out 1.5 turns it should run.   Then make fine adjustments to get best performance.

[953 nut 51,797]

11 hours ago, Daddy Don said:

Replace the spark plug and it took car of the problem. Hope this might help you out.

Did you  replace the spark plug with a new Champion H-10?

Here is a chart with the proper adjustments for carburetors

.

 

[Handy Don 10,642]

2 hours ago, 953 nut said:

 

Just a word of warning. This applies to original and OEM carbs. Aftermarket and 3rd party carbs may have different thread pitches on the needle valves--typically more coarse threading.

 

So far, every aftermarket carb I’ve installed came ready to run and I’m glad I did not mess with the needle valves before trying to start it. I only discovered the difference when I went to clean one a year or so later. 

 

Also, when getting ready to remove a needle valve, ALWAYS gently screw it in to the stop and write down the number of turns so you can put it back the way it was on reassembly!

[Daddy Don 893]

I will look and make sure what the plug number is.

[953 nut 51,797]

21 hours ago, Handy Don said:

o far, every aftermarket carb I’ve installed came ready to run 

I've only bought two Chinese carbs and they were both junk. One was a 26 mm throttle bore (ten to twelve horsepower) but was jetted for a fourteen to sixteen horsepower engine and couldn't be adjusted properly. I replaced the main jet seat and needle with ones from the old carb and it ran OK but nothing worth bragging about.

The second one (I bought both at the same time to save on shipping) had a  throttle plate that wouldn't close all the way, it went into the circular file!   

[Sailman 1,134]

8 minutes ago, 953 nut said:

I've only bought two Chinese carbs and they were both junk.

 

I bought a small used Yamaha 50cc motorcycle for my grand kids to learn how to ride. Had trouble keeping it running and no matter how much I adjusted the after market carb, nothing changed. Disassembled it and found both low speed and high speed adjustments.....were not even functional! Just for show.  Replaced the chinese junk with an OEM.

Edited October 4, 2023 by Sailman

[Handy Don 10,642]

So clearly I’ve been lucky with the three carbs I’ve gotten (snowblower, tractor, chain saw)

Do I quit while ahead or keep going? 

[Daddy Don 893]

18 hours ago, Daddy Don said:

I will look and make sure what the plug number is.

Plug # is BPR7HS

NGK R

[pfrederi 17,148]

1 hour ago, Daddy Don said:

Plug # is BPR7HS

NGK R

 

 

H10 c  or Autolite 216 or NGK B-6L

[Daddy Don 893]

Did you get your WH working okay?

[Jon Paulsen 282]

I'ma gunna pass on this deal:
 

https://www.sparkplug-crossreference.com › convert › NGK_PN › BPR7HS

NGK BPR7HS - Alternative spark plugs - Spark plug cross reference

NGK BPR7HS - Alternative spark plugs. There are 60 replacement spark plugs for NGK BPR7HS . The cross references are for general reference only, please check for correct specifications and measurements for your application. Specifications for NGK BPR7HS. Thread diameter: 14mm. Thread reach: 12.7mm. Seat type: flat. Hex size: 21mm.