1990 Suzuki LTF 250 soot black plug

[itfrk]

I rebuilt the carb, the pilot screw is located near the engine head to i assume its fuel adjustment and not air.

I can screw this all the way in, back off one turn (tried tight to fall out loose at 1/4 turn increments nothing changed)

and it will start and idol but if you touch the throttle it dies, you can ease the throttle in and get higher RPM but it is choppy, black smoke like the dickens.

carb is spotless. need help. I have to remove the carb every time to adjust this pilot screw as its in an impossible location to adjust while on the quad and im ready to burn this thing.

text nine one eight two zero eight two seven 82. or ill keep an eye on this thread ,, october 11th 2011

[pete59edsel]

Dry, black, soot-like deposits. Caused by rich running. Check carb mixture settings, float level, choke operation, air filter..... How many carbs have you done??

[itfrk]

Worked on a lot of mower carbs. This one has me against a wall. Float has no adjustment other then bending the tab on the float that presses the valve into the seat. There is no seal in the float valve Chamber either. But I checked that the fuel was sealing by the float valve. The moon clip is set to the middle slot on the needle. No seal on the choke valve. But I cut the cable and seated the choke all the way closed and sealed it off with silicon. Trouble seems to be the pilot circuit idol to 1/4 throttle. But then again it starts first press of the button. Idols fast, slow revs. Touch the gas and it dies. Before installing a new Carb kit this Wheeler would run good till it got hot the ran like crap. Had no top end power or speed.. guzzled gas. And smoked.

[quadnut20]

Worked on a lot of mower carbs. This one has me against a wall. Float has no adjustment other then bending the tab on the float that presses the valve into the seat. There is no seal in the float valve Chamber either. But I checked that the fuel was sealing by the float valve. The moon clip is set to the middle slot on the needle. No seal on the choke valve. But I cut the cable and seated the choke all the way closed and sealed it off with silicon. Trouble seems to be the pilot circuit idol to 1/4 throttle. But then again it starts first press of the button. Idols fast, slow revs. Touch the gas and it dies. Before installing a new Carb kit this Wheeler would run good till it got hot the ran like crap. Had no top end power or speed.. guzzled gas. And smoked.

Your running really rich !! The pilot is a jet (which controls idol to 1/4 throttle ) not adjustable you can change its size but as far as I know its not adjustable ! Air mix screw usaully is turned out at least 2 or so full turns ! I`m not understanding the thing with cutting the cable and using silicon on it ??? Do you have a manual on it ?

[itfrk]

The choke cable was already broken .I cut it off closer to the carburetor and add a little silicone around the boot it wasn't leaking anywhere . And I have been adjusting the pilot screw. It does not seem to be changing anything

[Senator]

The fast idle could be from fooling with the air screw to compensate for the additional fuel. Quadnut hit it on the head with the two turns comment. If it won't start, idle and run clean with the air screw approx two turns then one or more of the circuits (choke, pilot, main) is ill-adjusted to the needs of that engine. Start there.

[itfrk]

It will start and idol perfect now with the screw at one turn. My son can run it around the yard in low range. But you touch the throttke beyond fast idol and it starts black smoking and cutting out and dies

[quadnut20]

It will start and idol perfect now with the screw at one turn. My son can run it around the yard in low range. But you touch the throttke beyond fast idol and it starts black smoking and cutting out and dies

try turning it out 1 more full turn and run it !! Pull your plug and see what color it is !

[Ajmboy]

I agree, running very rich.

* Added ATV manufacturer to thread title.

[itfrk]

I have adjusted the pilot screw as suggested . and idles fine . Spark plug it is a nice brown tan color . But once you pass 1 quarter throttle , black smoke and it will die . I have the half moon clip on the needle valve set to the highest slot . I will post a couple pictures of the carburetor later when I figure out how

[quadnut20]

I have adjusted the pilot screw as suggested . and idles fine . Spark plug it is a nice brown tan color . But once you pass 1 quarter throttle , black smoke and it will die . I have the half moon clip on the needle valve set to the highest slot . I will post a couple pictures of the carburetor later when I figure out how

You need to rejet !

[itfrk]

ok rejet. but here is the issue, i ordered a carb kit and put in all the jets that came with it. should i try to

put back in the old jets i removed and see if that helps?

Edited October 13, 2011 by itfrk

[quadnut20]

ok rejet. but here is the issue, i ordered a carb kit and put in all the jets that came with it. should i try to

put back in the old jets i removed and see if that helps?

No I would figure what size jet they sent you !! That my be your problem !

[itfrk]

OK. I'll try and determine the current jet Size. Do you have any suggestions as to where to buy jets? Are They standard sizes ? I just received a Cylmar repair manual for this ATV but havnt. Had a chance to check. It out.

[marioweldinginc]

make sure your jet kit is not a knock off. Ive seen the thread (cant remember where it is for the life of me now) for ebay knock offs with wrong jet sizes stamped on them

[itfrk]

Got my carb kit from mfgsupply.com

[itfrk]

I used a float gauge and set the floats to 12.5 mm

Set the needle adjustment to the fourth slot.

And made sure all the jets were the correct size .

Reassembled and installed the carburetor for the 100th time

Hit the starter and it fired right up . Idle perfectly .

I hopped on it and and hit the throttle , and left a cloud of black smoke , would not run for crap !

I give up , I hauled it to the suzuki dealer

[hangingon]

sometimes we have to give up and take our quads to the shop.