I got into the carb one more time. Found a torn oring on this fuel/air mixture needle loctated at the engine side of the carb. (Assemlbed in this order, needle,washer, spring, oring.) I found it unusal that there would be an oring at this location? However I'm going to replace it. I believe it may have gotten torn when I set the screw all the way in, thinking if there was any trash in jet it would push it thru. I believe the end of the spring sliced thru the oring.

Reviewed other posts, Im thinking this could be called the slow jet and needle. The adjustments posted stated that the start setting is 1-1/4 turns out from full in.(If I dont cut the oring again!) with no more than 3 turns out and no less than a 1/2 out from full closed. I assume turning needle in is leaner and turning needle out is richer. This is a very hard to reach screw once the carb is mounted.
Questions:1) What is the correct setting
2) Can you tell when you got it tuned in by the sound:ie highest rpm before running lean.
3)What is the best approach to getting at the screw in order to set it.(Thinking I can twist the carb a little ,(so I can get to the screw) with no air cleaner hooked up.
4) Do you think it can be the valves are out of adj.
ATV*LT-F250FY-w/original Mukuni carb 2000 model with 1256 miles. Only changed spark plugs,air/oil filters and oil, and what is posted below. Oring on float needle and just recently a new float seat and needle.

<u>Here is my previous post:</u>

My son was riding in the back yard, he told me the machine backfired and then he could not keep it running unless he held the throttel open.
I checked the carb once before about two years ago and replaced the oring around the needel and seat,( at that time we were getting to much gas, gas was leaking around the oring and over filling the bowl, causing it to flood and back fire. That cured it for some time. So I figured it was the same problem.
This time I purchased a needle and seat assembly for !@#$%^& $46.00. Replaced the needle and seat assembly. I was so sure this was going to fix it. It did not. Sometimes it will try to fire but only with the throttle wide open and then it only fires for about 2 seconds. I'm getting good spark. What the &@!! could it be. Some one told me I could have dropped a valve, but when I pull the plug and place my finger on the spark plug hole I can feel the vacum and then feel the compression. But if I dropped a valve I would think that the engine would not even try to run as mentioned above.

 

Did you read my latest thread? If you haven't read it after reading this one.

http://forums.atvconnection.co..._key=y&keyword1=ozark


"What is causing the surging of rmp at idle?
If I rev it up in neutral it sounds like it's popping or backfiring just a bit.
But when I get it on the road and Run It Like I Stole It it get up and goes. But 3rd gear will have a little hesitation about at the second/third of the gear range. Once I past that range it get good again? "

Long story short; sounds like the exact same problem that I had. This all happened to me also.

Pull the vacuum line from the vacuum petcock to the carb (should be no fuel present) if there is the vacuum petcock diaphragm has ruptured. Otherwise it's trash in the carb or a bad tank of gas. Pull number 53.
http://216.37.204.203/Suzuki_O...asp?Type=13&A=123&B=5


1) What is the correct setting; Air/Fuel mixture screw needs to be approx. 2 7/8 turns to 3 turns out from seated.
When installing the o ring is rolled on the needle. Not placed inside the hole and then thread the needle in with the spring and washer.

2) Can you tell when you got it tuned in by the sound:ie highest rpm before running lean; read this webpage; http://www.motorcyclecruiser.c...jet_kits_carburetion/


3)What is the best approach to getting at the screw in order to set it.(Thinking I can twist the carb a little ,(so I can get to the screw) with no air cleaner hooked up.
Which screw pilot jet or air/fuel mixture? For the pilot jet take the carb out or take the throttle, choke, fuel inlet, and vacuum loose, then loosen the hose clamps and rotate the carb. For air/fuel; it's right on the side of the carb no need to diassemble anything. (given the side plastic is already off).

4) Do you think it can be the valves are out of adj? Did you already have them adjusted after about 4 tanks of gas? This is probably not the problem b/c it sounds like it just started messing up. (which leads me to believe it's the vacuum petcock)

 

Youngblood250

[img]i/expressions/face-icon-small-happy.gif[/img] Thank-you. Theres a wealth of information here. Once again thank-you. I managed to get it running, before your post. But I.m not satisfied with it just yet. See my latest post http://forums.atvconnection.co...id/12/threadid/522600

Your information and references to various post and web site diagrams was just, it was, well, just what the doctor ordered. Thanks again. Hey, I want to question you on you refering me to the web site and pulling item 53. What year and model were you refering to? I pulled mine, a LT-F250FY (year) a 2000 Model, and there was no ref. to a vacum petcock. I looked up the carberator, the fuel tank, the fuel pump and a host of other things, but could not find the vacum petcock. This was a good web site by the way, thanks.
The carberation fuel circuits, throttle indexing, jettings, needles sets positions it was all good information. It will be about 10 day before I get my hands back on the machine. Leaving south Alabama to Hazleton Pa. and visit sister.

 

Sorry, it looks to me that you have a regular petcock. Do you turn it on to ride and when you are finished you turn it off?

Also, sorry again the air/fuel mixture screw is harder to get to then mine and it should be 2 and 3/4 turns out from seated. Look at item 26 under "carburetor" the 2 3/4 means just that.

Petcock is under "fuel tank" item 16

Under "carburetor" what does the boost hose do? item number 45 under carburetor?

Believe me it's frustrating. I worked on my Ozark for two weeks and finally found out I could have fixed it when I was on the trail instead of packing and going home. Your welcome.

 

Petcock:this vehicle hasan automatic type diaphram style fuel valve. There are 3 positionss"ON"RES"PRI" ON position-the normal position for the fule valve is in the ON position, in this position, no fuel will flow from the fuel valve to the carberator unless the engine is running or being started. RES is just that, RESERVE it functions the same as above. PRI=PRIME position will allow fuel to flow from the valve to the fuel pump. this position is used for checking the fuel supply system. As stated in owners manual

I keep it in the ON postion, I personnaly dont like it. Owners manual WARNING statement claims to keep it in the ON or RES position so the carb wont overflow and cause a fire.

I will reset the screw from 7/8 of a turn out to 2-3/4's

And I will check that line. At one point I thought maybe these lines might be blocked or something and I tried to blow into and suck on the 3 lines going to the carberator (excluding the fuel line) nothing happened. And I dont recall the order of gas or tasting any fumes when I did this. I thought one would be a vent to the tank, I,m sure the others go to the fuel pump. It was months ago when I first got into it and I just dont recall were they go at this time.

 

Youngblood250

Hey, I reset the needle to 2-3/4. I found gas in the vacum line going to the pet ****. This vacum pulls a diaphram to allow gas to flow. I think it might even assist the vacum operated fuel pump (Does it?) I checked the dealer to see if I could get a diaphram-NEGATIVE I have to buy the petcock @ $70.00. WOW - Do you know of any company that would have a better price. Or can we improvise and put a different petcock on it?

I pinched the vacum line to the petcock, turned the flow to on, which is suppose to allow the gas to flow with out needing the vacum pulling on the diaphram to open flow. Pulled the spark plug. Pulled fuel line to carb and cranked to see if any fuel would pump out. Had to put the spark plug back in to get vacum-dah. No fuel, but when I unpinched the vacum line to the pet **** and cranked was getting fuel out of pump. But I had to remove the hose off the fuel pump. Gas would not pump out at the carb side of the hose, (hose is not clogged either) which makes me wonder if the petcock diaphram dont somehow help assist fuel pressure to fuel pump. Im thinking I may need a pump and a diaphram. I mean pet ****. Its a MIKUNI pump and a TAIYO-GIKEN petcock..

 

Errr

 

Sorry rudypoot.

Haven't been on the forum for a long time. I replaced my petcock with one from a 350 Yamaha Wolverine. Same bolt pattern except it's a manual one. I plugged the vacuum like on the carb with a vacuum cap. Sorry for the late reply.