02mx-5
New member
I took the governor off of my 5hp flathead and now i am looking at how much the throttle opens. It seems like the valve in the carb does not open 100% when the gas is pinned. How can i change that? Ive got a stock carb
help me with WOT
- Thread starter 02mx-5
- Start date
- Status
02mx-5
New member
yes i did remove it. What im saying is the throttle does not open all the way. The throttle in the carb. The butterfly valve? Lets say when the engine is idling the valve is 10% open. When its at full throttle, meaning the cable cant pull the throttle open more, the valve is only open maybe 80-90%. Is there a way to change that? Can i just bend the piece of metal on the carb so that it can swing open more?
anderkart
Moderator
If you posted a pic of how your throttle cable attaches we could give you better advice here, but usualy its as simple as loosening the clamp that holds your throttle cable housing and sliding/adjusting it back further away from the carb as necessary. If your cable retainer doesnt work this way you'll just have to do what evers necessary to get the carb fully opening.
After fixing it, make sure the carbs butterfly is still fully closing to the idle position so your kart doesnt take off and run away the first time you re-start it...
After fixing it, make sure the carbs butterfly is still fully closing to the idle position so your kart doesnt take off and run away the first time you re-start it...
On Briggs flathead carbs there is a small tab cast into the body that acts as the throttle stop. Use a dremel and grind it down SLIGHTLY just until the butterfly opens completely. Don't take off too much, or you'll be back where you started in the other direction.
02mx-5
New member
newrider, you seem to have the right idea. The linkage that is outside of the carb, but connected to the butterfly inside, has a stop, it only swings so far and then hits the carb body. If i bend the linkage so it doesnt hit the body , is that all i need?
02mx-5
New member
no, my cable is not holding the throttle open. Everything is set up just fine. I am telling you that the throttle does not open 100%. It may not be open 10% at idle, but im using it as an example. Its open a little bit for idle, and when i rev it, even if i use my finger to push the throttle, it only goes so far. It has nothing to do with the cable. Like newrider said, it has something to do with some kid of stop. I have work right now but i will upload pictures later or tomorrow.
anderkart
Moderator
Yeah it sounds like somethings bent out of shape there. Lots of karts dont have any type of throttle stop on the gas pedal, so when you push down hard this can end up bending the carbs throttle shaft, butterfly, bellcrank or meyby just the carbs bracket that acts as the full throttle stop point.
BriggsTwins
New member
2nd that ander, this sounds like you have an issue with something. do you really need 100% throttle?
02mx-5
New member
Do i need 100% throttle?! Im sorry but what kind of question is that? Of course i do. More throttle, more speed. Cant go wrong with that. I may not use it all the time but its there when i need it. Here are two pictures of the linkage. The picture with my finger in it is at full throttle(or what briggs calls full) If the butterfly valve was 100% open, the arm with the spring on it would have to swing farther over the carb body than it does. Can i bend the arm up so it clears the carb? http://photobucket.com/02mx-5
02mx-5
New member
And yes, i know the carb is filthy.
anderkart
Moderator
I'd expect the arm on the bellcranks opposite side (top of pic) to be your WOT stop. But from your pics angle, this doesnt apear to be fully reaching its stop point. Is it?
If not and you find something else is limiting the bellcranks rotation, you've likely found your culprit. If it looks like a carefull bend will fix the problem, give it a shot.
02mx-5
New member
yes, the part in the top of the picture is what hits the carb body and stops it from moving. Its hard to see that from the picture. The side with the black plasting bushing and linkage is not hitting anything. Is that part the one you think is hitting?
02mx-5
New member
I just realized, did you think my finger is there to point out where it is hitting? Im actually pulling the throttle open, where im pointing has nothing to do with the picture. Sorry if that pictures a little confusing
anderkart
Moderator
If the "part on top" is fully reaching its stop and not allowing the throttle to fully open, try bend in it to allow more movement.
02mx-5
New member
Ok. Thats what i have been thinking but i wanted to make sure it wouldnt break or damage something internally by turning to far. Ill give it a shot and see how much of an increase i get. I need to throw in some stiffer springs before I run it again. I let everyone know my results.
anderkart
Moderator
When bending things like this, sometimes its best to use a second pair of pliers/needle nose to help support the mounted end...
- Status