my carburetor is so unpredictable.. W114

[evoldeal]

One day out of nowhere i start up my 73 280 and the engine went into a high-rpm warm up mode. Usually if I feather the gas a little bit it'll calm way down once it's warmed up and before I shift into Reverse. It never calmed down... and it often bucked into gear.

I brought the idle screw all the way down on my weber dgas (the one that presses into the butterfly gear) and had to turn the idle mixture screw almost all the way in to get the idle to calm down. The problem was when I shift into gear, the idle drops to a sputter. Somewhat manageable but doesn't feel ideal at all. Also it gives off a gassy fuel smell when you accelerate (meaning a rich mixture).

Well i leaned it out again by opening the mixture screw a few turns, and it runs so much better and the fuel smell is gone. However it does feel a bit supercharged and I feel like the brakes are really holding it back at a stop light.

I also noticed a WHIRR or WHINE when sitting at stop lights. Otherwise the idle sounds much better. But the WHIRR does worry me a little.

Attached is a video trying to capture the whirr sound. You can hear it at the beginning and then again at the end more clearly just before I shift into park.

Can anyone pinpoint this sound? i've not heard it before and I hope it's not something straining under the pressure of the carb mixture.

and where is the happy medium on a weber carb? Has anyone had good results using the Weber calibration guide that is published online?

73 280 idle - YouTube

[meltedpanda]

do you have a vacuum leak? If this started suddenly then I'd check the two things that make an idle high, too much fuel and two much air ( that is if the linkages are not stuck, choke ect all functional)

[evoldeal]

thx panda,

the linkages are free and clear, and the choke is operating properly. you are right a vacuum leak would make sense.

How to locate a vacuum leak is beyond me. I'll do some reading on it.

[meltedpanda]

carefully spray carb/intake cleaner around the intake manifold and throttle body, with the engine running. if you get around the leak the engine speed will change as a result.
Also around any suspect links......no smoking

[evoldeal]

hey thx again!

would i do this with the air filter mounted or removed??

and yes no smoking!

[meltedpanda]

on