Carburetor trouble

[Highliner]

I have a atc 250 es 1985, I have trouble with my carburetor, I clean it and replace all the jet, needle, gasket include in the repair kit, I loose my pilot screw with 2 turn. I put my carb and start my engine, sound great, but when I give throttle the engine want to stop and when I release, the throttle is good.

Any idea?

Thank

Dom

[tri again]

Hi and welcome and congrats on going thru your 250 carb.

It sounds like all of mine when they are cold.
Stumbling when you hit the throttle.
If the choke is working correctly, that should help
for the first few minutes.
It takes a few minutes for them to warm up and then they run great.

Did that choke enrichment piston move freely?
Does the cable and slide lever move good both ways?

On some early carbs the cold start jet is a little too small
and can cause hard starting but they generally run ok once
started.
Did you blow out the internal passages in addition to the jets?

There are manuals under the world class help section
and the search key should get you tons of info on 85 carb issues.

The 'trikesylvania' forum gets TONS more fix it traffic but I'll try to attach
a couple things that may or may not be significant.

Has it ever run well for you?
is it new to you?
good new gas?
gas tank vent working ok?

Please let us know what you find.

[Robin M]

Drjoe covered pretty much everything but just some other pretty minor things to check. Is the new needle you put in slotted in the right position. After rebuilding your carb your pilot air is the two turns out, but once you get it idling turn it in till the motor stops, then back out one turn. Is your float moving freely and set properly. Also, check the plug, should let you know wether your over-fueling it or starving it.

[cbx1170]

Did you just get it out? or just buy it? Are you sure fuel is good. Just mixing in some good fuel with old gives you a lot more bad fuel. Either way drain all fuel and put in fresh. Put the old in your car. Eliminate problems like old weak gas. Good spark plug? Crappy gas coats everything in your cyl head valves spark plugs combustion chamber.

Do you have a KNOWN good air filter? Run without air filter for a few minutes. I drove 20 min to a friends house to a nearly non running 185s choked splatting ran very bad air filter LOOKED good but i pulled out and trike ran perfect.

Lastly Honda 4 stroke carbs need good JET NEEDLE and NEEDLE JET (like p/n 16012-HA0-003 NEEDLE SET, JET ) combo sets to run right. If you look close at right spot on upper needle you can see the wear/corrosion. they both wear together and it ends up too rich. Some aftermarket needle/jet combos are wrong out of the box.

[cbx1170]

this is some of the neatest carb cleaner out there. Good for most carb cleaning. mix 1 part Yam cleaner : 3 parts gas OR 3 parts HOT WATER
yes it WORKS. Let sit upright in carb bowl with ALL the loose parts inside bowl and in the morning DRAIN and flush/blow out carb. DO NOT TRY AND RUN ENGINE IT WILL NOT BURN!!! EVEN WITH 3 parts FUEL!!!!

http://http://www.boats.net/parts/detail/yamaha/Y-ACC-CARBC-LE-NR.html

http://www.amazon.com/Yamaha-Carburetor-Cleaner-32oz-ACC-CARBC/dp/B002GU4SPA