Main jet needle valve
 

I've got a question.

I'm rebuilding a Kohler adjustable main jet carb on a replacement motor in my 125.

Here is a side pic to confirm what I have:

Attachment 42861Attachment 42862Attachment 42863


So, here is the question. The original main jet needle has four holes at the top, and two at the bottom. I am going to replace the main jet, so I ordered one. In my parts book, it showed two listed. In the pics, it showed one with a spring, and the other didn't. I assumed that was the difference in the parts, so I ordered the one with the spring. Well, when I got it, the new needle valve only had one hole at the bottom, and two at the top. So, I ordered the other one. It came today, and sure enough, it is just like the original. My question is, since both are listed as needle valves for the K series Kohler carbs, why do they make the two different valves? Is it for a different application? Like perhaps a speed limiting, constant governor and the other for the variable speed governor like on the Cubs? I'm going to make a notation in my parts book, so I know which one is which. Just wondering why there are two different styles. Anyone? :bigthink:


Pics of the holes I am referring to. This is the old jet.

Attachment 42864Attachment 42865

Sorry the parts aren't clean yet. Just took them out of carb cleaner and haven't started scrubbing them yet. :biggrin2:

I can't read it very good, but is your Carb a Kohler C-233315...???

Close! It is C-236315. Sorry, I should have noted that in the text, instead of relying on the pic.

feed to the idle curcuit

Don, do you know why they offer 2 valves? Different application? I know they feed the idle, but not sure why one feeds it more fuel than the other since the idle circuit has it's own needle valve. I don't see any reason why you would ever need the main needle valve with the lesser holes. :bigthink:

not positive. may be used in an engine that runs a steady rpm like on a generator. it don't really idle. or it could just be a new part that possibly has a reduced fuel feed for emissions? not real sure. when you think about it the idle circuit works with an air bleed style system. so it may draw the same amount of fuel but it may have to have the idle screw set differently. are the holes the same size?

looked at all the spare needles I have and they are all 2 hole on the bottom. 4 on top.

Yes, the holes are the same size, just fewer of them. I agree with you, I think it may be for a speed limiting governor set up, where the engine doesn't idle. I am just curious at this point. I got the correct one, and I'll be sending the other one back. Like I mentioned, I made a note in my parts book as to which one is which, but couldn't figure out why you would want to limit the fuel to the idle valve. I was hoping you would answer, and it sounds like we are on the same page. Thanks Don! :beerchug:

Is this Carb off a Kohler K-301-47504...???

I'll have to get back to you on that. I'm at the shop, and tractor/motor is at the house. I do think if you look it up by the motor number, it is going to show the valve with the 4/2 hole combination. That is what I pulled out of it. I'm more interested to know what the 2/1 hole combo valve is for. Like I said, I'm curious at this point..... but I'll get the motor number and post it a little later. :beerchug:

Ok, sorry it took so long. Here are the numbers:

K301A
Serial # E0013524
Spec# 47138B

Thanks Roland!