Initial Carb Settings ?

[Digger 66 3,488]

I just finished rebuilding my carb on my Raider 10 ( '72 ) .

The guy I got the kit from said to lightly seat A & C , then adjust out 1 & 1/2 turns & it should be good to roll .

I did as he said, but it doesn't seem to want to throttle - up quickly from idle ? is this normal ? 

B is obviously the Idle speed adj . 

Would I be correct in assuming that C is the fuel/air & A is the main ? 

Or if anyone has any additional suggestions I'd be grateful .

If need be , I can pop a video up .

Thanks guys .

-Gene 

 

Here's the # stamped into the carb's spigot , if it matters :

 

[Digger 66 3,488]

Let me try to better describe.

Cold start : fires up with half choke & runs OK . As it warms & you start backing off the choke , it starts to pop& wants to die. These 1&1/2 turn out seem too lean to me.

Which screw do I begin messing with (A or C ) ? To achieve optimum results?

Let me also add : the carb is now spotless , new fuel lines & filter , the tank was removed & flushed clean as well & the fuel pump appears in good condition.

It was running OK until the new settings were incorporated.

Edited August 14, 2013 by Digger 66

[Kelly 1,030]

I turn them out 2.5 turns each and warm engine and adjust from there. 

[rmaynard 15,932]

Don't know how deep you went into the rebuild process, but if it spits and sputters when you unchoke it, that sounds like you have a worn throttle shaft/bushing. Also, did you clean all the little holes in the shaft of "A", and make sure that the inside of "A" tube is clear and free of debris? The brass pointed tube with the little holes is hollow and must be clean.

[Digger 66 3,488]

Yes ^ the throttle shaft bushing is worn , good call .
Are these available online ?
The kit did not come with one
& yes , all the passages in the items you mentioned are clean . Sprayed with carb cleaner till it ran clean then blew with compressed air.

 

 

 

Edited August 14, 2013 by Digger 66

[Kelly 1,030]

your never going to get it to run correct with that much play in the shaft, I'll see if I can find the bushings I use and post a link. 

[Jeff-C175 7,203]

Wow... that's REALLY worn!

 

I didn't see where this got a direct answer:

 

 

Would I be correct in assuming that C is the fuel/air & A is the main ?

 

A is the main (hi-speed) jet adjustment, C is the idle mixture adjustment.  (yes, B is the idle speed)

 

After you get that bushing problem ironed out,  for adjusting... the way I usually approach it is to get it running well at idle first.  So adjusting the idle mixture is the first thing.

 

Then, run it up at full throttle and adjust the hi-speed mixture.

 

Back to idle... readjust if necessary.  Run the idle needle in until the engine slows a bit, then back out about a half turn.

 

Same for the hi-speed, in until it slows a bit, then back out about a half.

 

I might go a little on the rich side on the hi-speed because when a load is on the engine as in actually travelling and mowing, if you set it with no load, you might end up a tad lean when operating under load.

Edited August 14, 2013 by Jeffpicks

[Digger 66 3,488]

your never going to get it to run correct with that much play in the shaft, I'll see if I can find the bushings I use and post a link. 

I was afraid of that ^ 

I called my parts guy around here & it seems there is a repair kit offered ( though I don't know the #'s ) for around 40 bucks . 

I don't have a problem with dropping the dough , but making stuff yourself is waaaay more fun , especially when it works .

I'll still appreciate your reply .

[Kelly 1,030]

This is not where I got mine but it's the same thing.

 

http://www.mowers4u.com/kohler-kohler-carburetor-throttle-shaft-bushing-p-873.html

[Digger 66 3,488]

This is not where I got mine but it's the same thing.

 

http://www.mowers4u.com/kohler-kohler-carburetor-throttle-shaft-bushing-p-873.html

 

 

 

Thanks for the link ! 

I guess now I'll have to see if the bushing is worn so badly that the shaft began to dig into the spigot itself .

My guy tells me that some of the bushings were made of neoprene & some brass or Oilite .

I will rip it apart after work tomorrow & brace myself for the worst . HaHa .

Meantime , Thanks Jeffpics for the setup guide , I'll use it ! 

 

One more question , is there a matching bushing at the other end of the shaft ( inside the boss ? ) or does it just pivot inside the body ?

Edited August 14, 2013 by Digger 66

[rmaynard 15,932]

The original carburetor never had a bushing for the throttle shaft, just a machined hole in the casting. Over time, both the hole and the shaft get worn. The recessed area in the top of the carburetor around the shaft is about 1/8" deep, and when the new bushing is pressed into place, it gives the shaft a new surface to ride in. So now you have a perfect sized hole, plus an unworn area of the shaft is in the bushing.

 

Now here is the cavaet. With that much wobble in the shaft, the hole in the bottom of the carburetor may be worn as well. That usually requires the services of a machine shop to bore out the hole and insert a bushing. However, of the 3 carburetors that I've repaired the top hole, the bottom has been okay.

[sorekiwi 761]

As a rule of thumb, if I don't have advice on where to start for carb settings I will set them 2 turns out from seated.  It seems to be a workable starting point on most gas engines, tractors, weed wackers, chainsaws and carb equipped cars.

[Moparfanforever 874]

Before you take the shaft out , mark the butterfly plate so it will go back in the way it came out. It has been my experience they only like to go back in the way they came out. I use a Sharpie to do it.

 

You will have to file down the threads on the two brass screws so they will come out without breaking them , and then,just to be safe, you will have to work them in/out as you try to screw them out. They are split at the threads so they won't back out.

 

You will need new screws also. I put Loctite on the screws before i put them back in. Use blue Loctite if you ever plan on taking them back out , use red Loctite if you want them to stay forever !!

 

Looked at the link Kelly posted and i see they include the screws , so you will be set !!!

Edited August 15, 2013 by Moparfanforever

[rmaynard 15,932]

The secret to backing out the peened screws is to turn them about 1/8th turn, then back in, then 1/4 turn out, then back in, and so on until it comes out.

[Moparfanforever 874]

The secret to backing out the peened screws is to turn them about 1/8th turn, then back in, then 1/4 turn out, then back in, and so on until it comes out.

 

You have better luck than me !! I tried that one time , and the first screw broke. It only takes a few minutes to file down the threads on the screws , so i just do that to be safe.

[Digger 66 3,488]

I'd say she's a "bit" egg-shaped 

The shaft's dia. is 1/4 " but the outside of the bushing seems a little odd , going to visit my local hardware guy & see what I can come up with to finish the season .

Come winter , It will be fixed properly , but for now I need to get the rest of the season out of it . 

 

 

[Jeff-C175 7,203]

Maybe a big fat O-ring to get you through the season?

[Digger 66 3,488]

Nope , threw down the 50 clams for the genuine Kohler shaft repair kit .

Done !

[Jeff-C175 7,203]

What was in the kit? 

[Digger 66 3,488]

The bushing , 2 butterfly screws , new throttle shaft , screw for the top of the shaft ( for reattaching the linkage arm after you grind the peened part off ) new bowl screw gasket , new bowl o-ring & seal , Loctiteâ„¢ & peace of mind . LOL .

Kohler ® P/N 25 757 16-S

Edited August 17, 2013 by Digger 66

[rick 245]

Fixed it right, the first time. Way to go!