79 vanagon backfiring through carb?

[Dennovw]

I have a 77 vanagon with a 79 california motor in it. It's backfiring through the carb. According to the distributor my timing is supposed to be at 7.5º BTDC. So I set it there and it's still doing it. It won't idle on its own, I have to keep on the throttle. I set the timing with a test light on the condenser and a ground, after putting the notch on the crank pulley inline with the 7.5º plastic timing tab. Any suggestions?

[peaceful warrior]

No such animal as a 77 Vanagon.
_________________
"Two things are infinite: The universe and human stupidity; and I'm not sure about the universe." Albert Einstein
"Notchboy" says "Man up!"
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66 13W Deluxe, 68 Westfalia, 87 Syncro.
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Brian

[Wildthings]

Neither US '77 or '79 Transporters came with either single progressive or dual carbs, so whatever you have is far from stock.

[dhaavers]

[Dennovw]

Yeah sorry about the vanagon thing. The guy who owns it asked me to post this, told me it was a vanagon. I'm just now getting into the busses. I thought it was a bay but went against my better judgement. It was taken from FI to carb btw. Anyway, thanks, post moved.

[Wildthings]

Valves not closing or seating fully can cause backfiring, so check the valve adjustment and do a compression test.

Intake leaks and exhaust leaks can also cause backfiring so check for both. The intake boots on a progressive manifold set up are suspect as are the manifold to head gaskets.

A lean running carb or timing that is way off can do the same. Progressives typically get jetted way rich to overcome the dead spot off idle, but who knows what has been done to this particular setup.

The best timing is 28-30° BTDC at 3500+ rpms, hose(s) off.

[Jake de Villiers]