"Crackling" sound from Webers and MSD Install on 1971

[JohnJL]

Hi all, been a while since I posted, have been moving house and finishing up my latest project, Mike B's former 71 Targa that took a beating on the transit to Australia.

Mostly finished up the interior and sorted out a new alternator and MSD install (notes on that later.) The electrical system got melted when the guys at the dock decided to hook the batteries up backward.

It fired right up but some weird "crackling" noises were coming from the Weber intakes. I only let it idle for a minute or so, but often when I upped the idle with the accelerator or choke sounds kind of like electric static came from the carbs. Any ideas?

On the MSD, I believe my tach to be an original 1971 with 3-wire CDI. The CDI died (new ones are $600 here?!?) so I installed an MSD 6T and Blaster 2 Coil. It was pretty simple...

1. Removed the CDI and old coil and marked all the wires. There were 2 mystery blue and yellow wires on the positive coil. I don't know what they were but I re-installed them.

2. I had a Tach adapter and partially installed it (grounded it and connected its white wire to the tach output on the MSD). I didn't power it or connect the purple wire, wanted to see if things worked without it first.

3. My dizzy has points and 2 wires coming from the terminal. One went to the CDI black wire, I connected that to the MSD white wire. The other (purple? couldnt see it well) wire looks like it goes to the tach.

4. I connected the MSD heavy red wire to the Starter terminal.

5. I connected the small red MSD wire to the middle, red wire on the CDI harness.

It fired right up, I honestly couldnt tell if the Tach is accurate or not. This motor is new to me and was only idling for a minute or so (no seatbelts or road plates.) Next I'll put in the seatbelts and passenger seat, rear caps, innovate O2 sensor, and temporarily hook up a magnetic pickup to sense the Patrick Motorsports trigger wheel already on the car. Datalogging then begins to get the tuning nailed. These are my first Weber carbs...

So, any thoughts on the crackling noises from the carbs?

thanks

[Mo_Gearhead]

John, With a cold engine Webers can make, I call it a 'spitting' sound, perhaps you are calling it a 'crackling' sound? Usually caused by a slightly lean condition and cold engine.

There are many threads here on tuning your Webers. Do a search and you will find lots of good info.

Good luck with the new car!

[JohnJL]

Thanks Mo, I've prepped myself with Bruce's book, three separate Weber books and lots of reading here...hadn't heard reference to the noise I referred to but that's really subjective.

Lots of pages on MSD and tach issues so I thought I'd post what appears to have worked for me.

j

[RoninLB]

Originally Posted by JohnJL

So, any thoughts on the crackling noises from the carbs?

"crackling noises".. like the noise of an ignition spark jumping to ground?

[JohnJL]

dunno, but it jumps from left to right side...lets put some petrol in it, spin it up and enjoy the music!

EDIT: Yes Ronin, exactly like that.