Carter YF running lean

[shammydog]

Hoping there are some Carter YF experts out there! I just rebuilt my carb and it's now running lean. I think so because i have poor power with wide open choke / hot engine, runs worse with the air filter removed, runs pretty good with choke 1/2 closed engine hot. I followed the procedure of bottoming out the metering rod then one clockwise turn. I'm thinking I need to give the metering rod another 1/2 turn and see if that helps. Any suggestions from an expert?

 

[xctasy]

These two posts help best.

yep, its pretty simple. they are basic little carbs.

navigate to the link if the image doesn't display correctly:
http://oldcarmanualproject.com/manuals/ ... 19_jpg.jpg


i'm pretty sure its just a 'low speed jet' and a 'metering rod jet' but the 'metering rod' is also a tuning component, you might have a mis-matched metering rod (us motorcycle guys call them a 'needle') and jet.

here is the metering rod assembly.

If you buy a rebuild kit, they usually have that pic i attached printed out for you on a big sheet of paper, still might want to take photos of the stages of carb disassembly while you are doing it, however. Here is a picture i took from when i did mine.

Before changing jets I would try the metering rod adjustment. It has always fixed any YF mixture issues I've seen. The screw in the background raises and lowers the tapered rod in the jet. Raising it will fatten up the part throttle mixture without fattening up the WOT mixture, which I suspect is not too lean anyway. Plug readings at WOT mnust be taken after running the engine at WOT and not letting it come back down to idle while running or the WOT reading will be affected.

Modern plugs will tolerate a leaner mixture and may look white, even though the mixture is correct. This is especially noticeable on fuel injected engines.

My buddy John would always send his driver (aka his wife) down the track with a ratchet plug wrench and a spare plug. She would kill the engine at WOT, coast to a stop, change the plug in question, and bring the unsullied plug back to the pits for inspection. He was an absolute wizard at tuning Weber IR systems.

 

[jdn21758]

try you tube search by carter yf there they show you the problems with youre carb and how to rebuild.

greetzzzz ,,,JD