View single post by discogodfather
 Posted: 02-21-2020 02:18 am
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Joined: 09-17-2007
Location: San Francisco, California USA
Posts: 51
Tom Bradley wrote:
Additional thought: The choke on most carbs is dual-action. It increases the idle speed as well as the mixture. One possibility is that the idle screws need to be turned in to increase the idle speed when the choke is off. My experience is that the idle speed needs to be at least 500RPM to stay running at all. With your engine mods (especially the cams), it may have to be higher than that.

Thanks Tom,

I fiddled with it forever and didn't get anywhere until I came across a forum talking about DCOE's that said the newer Spanish Webers needed the idle mixture screws to be backed out further than the older Italians. The usual is around 1.5 turns from fully in to start, they recommended 4-5 turne out. With the 55F8 idle jets I was able to get her going and pretty smooth and without the choke. Easy enough to time the engine now and it's running at 1000 rpm nicely with around 10 degrees of advance.

The copy Lucas 43D is in there and running good. It has what Powerspark claims is a "high energy" electronic unit that looks pretty robust (it's all rubber coated and looks far less prototype like than a petronix) and it runs great with a low resistance (.7 ohm coil) and apparently runs "dry" and is an epoxy filled unit instead of oil. Used the Chicago Rawhide 4912 oil seal and it's not leaking a drop so far. No idea where the advance curve is, I have to measure it.

A video of it running on my youtube:

Now it's time to fiddle more with some progression on the carbs and figure out where she's running at, but great progress!

Last edited on 02-21-2020 02:19 am by discogodfather