cold engine starting issues on talon gx125
 

Pulling this carb apart is getting old. I have tested auto choke and it is working as described in test procedure. After driving buggy all day for hours, I let sit overnight and she just dont want start back up the next day!? It runs pretty decent and will idle after driven a bit. I crank it over plenty and after will check plug and is bone dry. I have removed vacuum pet cock and installed a gate valve so it has plenty of fuel to carb. If I give it a shot to the cylinder it will start and then run fine!!! What gives???:banghead:

Sounds like possibly an intake air leak, could be intake gasket or dry rotted transition piece between intake manifold and carb. If the leak is small enough or in the right spot, after the engine gets warm, things start to expand (metal expansion can seal the intake gasket leak if its not too bad). Try starting it with a "shot" and before it warms up too much, spray WD40 thru the little red straw in the area of the intake manifold gasket and other possible leak points to see if you get a noticeable change in rpm. Changes in rpm indicate a leak in the area you are spraying. Vacuum lines tend to harden up with age (due to heat from engine) and lose some of their sealing ability. Replace them if they are not soft and flexible. Check or retighten all bolts on the intake manifold and carb.

Ya know, I did have intake nuts come loose and I replace one and tightened other. I didnt bother to check condition of gasket! Good thought! Plug isnt showing lean condition but is obviously not wet with fuel either. Its actually very dry even without running. I'm planning on checking valve adjustment tomorrow but you gave me another good possibility, thanks! Is it a paper gasket or o-ring on these motors?

Best I can tell from the manual I found on it, they are paper or fiber, not o-ring. Check for yourself in the attached manual page 14.:)

There are numerous manuals from different buggy distributors using the GY6 150cc engine. They are almost identical in all respects. I happened to find one for a Talon GX125.

Great thank you! I'm gonna hope my local cycle shop can help me get new one or will have to find online. I'm in need of exhaust gasket to. Apparently I'm gonna have to keep an eye on the nuts and bolts on this engine!!

May be an o-ring on intake manifold, then against spacer, then against paper gasket, then against head. The images below may help.

All I can say is WOW!!! First I found o-ring torn on intake, repaired and still hard starting. Did my valve adjustment and I'll be damned!! Fixed!!! Dont anyone overlook how these guys on here overemphasize valve adjustment! My buggy will spin tires easily now and its bone stock!!! Thanks guys and girls!!!

Glad we got you pointed in the right direction:party: