engine and drivetrain Starts, Dies After A Few Seconds

[Philbert]

The 02 has been running well. But I started her up this morning and it died after a few seconds. Tried again, same thing and I noticed what appeared to be smoke coming from under the hood. I opened the hood and had my son start it. Started immediately, ran 3 or 4 seconds, quit and a cloud of fuel vapor gushed out of the carb. I noticed the engine actually ran backwards for an instant right after it died!! Didn't know that was possible but maybe it,s to be expected under certain circumstances? Weber 32/36. No issues in the recent past-I know the carb is due for replacement as the primary barrel is scored where the throttle plate contacts it but has been running well on CD's prescription for the last year or so. I don't think it's an ignition issue or valve timing issue, both were reset recently. As I say, it's been running smoothly, easy starts, 30 mpg highway. I'm planning on digging into it in the morning, thinking stuck float, clogged float valve or clogged idle jet. Any suggestions as to what else to look for? One other piece of info - if I get on the gas right when it starts, it will run, but then dies a few seconds after letting it drop to idle speed. More reason to suspect idle jet's gunked up??

Thanks, Phil in Seattle

[Mike Self]

Does your Weber have an anti-dieseling solenoid on the primary barrel idle jet?  It's a small cylinder with a male electrical connection on one end that screws into the idle jet orifice on the carb body.  Webers don't come with 'em but someone may have added it at one time.  If it's not functioning, there will be no running below about 2000-2500 rpm.  If you have one, you should hear a distinctive click come from it when you turn the ignition on or off (the solenoid opening/closing).  No click = dead solenoid.

 

If you don't have one, I'd definitely pull the idle jet and clean both the jet (a very small orifice on that thing--takes very little to plug it) and take your can of carb cleaner and give a healthy squirt down the jet passage before replacing the jet.

 

Hope that's all it is...let us know whatcha found.

 

cheers

mike

[Philbert]

Thanks for the response. No solenoid on this one... But I blasted out the idle jets with carb cleaner, ditto the mains, jiggled the power valve a few times, reassembled and she fired right up. Replaced the fuel filter for good measure. All problems should be so easy!

Phil