Weber 40 IDF help, My usual guy had back surgery and can't help now Options

[mmichalik]

Hi everyone,
My 75 is ready to drive again. I fixed the oil leak from the main seal a couple of weeks ago and all is good.
As I continue to do the shake out of the car, since I'm on the tail end of the restoration, I've had one problem the entire time and I need to get it fixed now.
Cold or hot, as I'm driving there's a flat spot when I shift between gears. It bogs and then picks up again.
It's particularly noticeable from 1st to 2nd and 2nd to 3rd. Sometimes even when starting for a dead stop.
I know NOTHING about carbs but I'm willing to jump in.
Does anyone have any experience with these symptoms? Is there a write up on the world that I've missed?
Would anyone be willing to work for high end craft beer and good pizza (along with an hourly rate) (IMG:style_emoticons/default/smile.gif) I'm in north county inland San Diego (Valley Center)
Mike

[nditiz1]

So 2 things will be needed, 1 of which is easy and the other will require a purchase and some welding (well they do make a bolt on bung)

1st we need to know what jets are in there now. Pull one from the side (idle jet), pull the top stack (main, air, emulsion). If these are brand new Weber IDF or even old stock ones you are probably running something like this:

50 idle
115 main
180/200 air (can't remember which one came factory)
F11 emulsion
28mm venturis

The 2nd item that is needed is an AFR gauge. I usually use an AEM UEOG wideband, but you can use whichever you like. They even have a fancy bluetooth one that shows on your phone so no need for an additional pod. You will need to have a bung welded into your muffler or exhaust. Preferably both sides, but one in the muffler should suffice. There is another option in LM2 (if memory serves) that connects to the end of the muffler tip to get a reading on AFR. Never used that one.

OR you can just keep making minor changes until it "feels" right, but you could be overly rich and not know it.

[Superhawk996]

The 2nd item that is needed is an AFR gauge.

Awfully nice to have but not a must have. There were no affordable AFR gauges back in the day and we got by just fine reading plugs, using the assometer, CHT’s, and monitoring fuel economy.

Glad to hear the ignition is 123 - makes life a whole lot easier.

Per Porschetub’s comment above, need a whole lot more detail on speed, RPM ranges, throttle position, and load (flat vs hill) to advise. Your gut instinct is correct; it is a lot easier if you can find someone local that has carb tuning experience vs doing it via internet advice.

Regardless of how you go about this - I highly suggest you keep a journal / logbook. Time / date, temperatures, jetting changes, ignition advance curve used, CHT’s, any details. Things can get very murky after a few days. Humans are not terribly good at recalling how one change vs another felt after only a few hours between changes. Doesn’t need to be overly fancy or complicated but document your baseline and what changes you make.

[930cabman]

The 2nd item that is needed is an AFR gauge.

Awfully nice to have but not a must have. There were no affordable AFR gauges back in the day and we got by just fine reading plugs, using the assometer, CHT’s, and monitoring fuel economy.

Glad to hear the ignition is 123 - makes life a whole lot easier.

Per Porschetub’s comment above, need a whole lot more detail on speed, RPM ranges, throttle position, and load (flat vs hill) to advise. Your gut instinct is correct; it is a lot easier if you can find someone local that has carb tuning experience vs doing it via internet advice.

Regardless of how you go about this - I highly suggest you keep a journal / logbook. Time / date, temperatures, jetting changes, ignition advance curve used, CHT’s, any details. Things can get very murky after a few days. Humans are not terribly good at recalling how one change vs another felt after only a few hours between changes. Doesn’t need to be overly fancy or complicated but document your baseline and what changes you make.

All good information and try to make just ONE change at a time to keep things in order