Backfires at carburetor, what should I try next?

[Devilish_02]

Car is a 1973 02, euro version. It was imported into Bogota after purchase and was there until I purchased a couple of months ago. Working my way through some issues and trying to learn as much as possible along the way.

 

Here is a quick recap but my question is below. 

 

 

It is backfiring at the carburetor. I read somewhere else that sometimes that can happen because there is not enough fuel getting to the carb. The float bowl was low and the fuel filter empty. So I replaced the filter and primed it with some gas. 

 

 

I can check if the plugs are getting a spark but because it backfired I assume it is getting some kind of spark. 

 

Thanks in advance!

Edited April 3 by Devilish_02
Errors

[BarneyT]

Jake it could be a vacuum leak causing the backfiring…after removing carb.

[tech71]

32 minutes ago, Devilish_02 said:

I did swap out the spark plug wires for new ones and even though I was careful it put them in the exact same order, maybe I got it wrong.

Or maybe they were wrong to begin with, easy enough to check

[Devilish_02]

@BarneyT the single barrel solex you helped me out with needs to be rebuilt. But I also have the weber 32/36 to rebuild. So if it may be time to make the switch....

[Devilish_02]

8 minutes ago, tech71 said:

Or maybe they were wrong to begin with, easy enough to check

Drove it on a weekend drive with some other Austin '02'ers so I don't think so....but.... 

 

If you don't mind answering a basic question, how would one check? Assuming you mean something more than double checking the plug wires are going in the same spot on the distributor cap, correct direct, sequence, etc. 

Edited November 20, 2022 by Devilish_02

[esty]

advance the timing a bit...just turn the dizzy slowly in the direction that increases RPM's

 

 

['76mintgrün'02]

1 hour ago, Devilish_02 said:

how would one check?

 

ZUNDFOLGE!   

 

['76mintgrün'02]

59 minutes ago, esty said:

advance the timing a bit...just turn the dizzy slowly in the direction that increases RPM's

 

He's got a 123, so it needs to stay clamped in the proper position and changes in advance need to happen over the phone.

(assuming it's clamped in the proper position now)

[paulyg]

Your advance changes in the app will be relative to the position that the 123 THINKS TDC is (the engine was supposed to be at TDC when you were hunting for the green light at setup). Worth checking timing with a light after install and verifying that the advance shown by the timing light matches the advance the 123 should be pushing under the given conditions. 

[Devilish_02]

Followed @BarneyT suggestion. The phenolic gasket at the base of the solex carb had a crack in it. Also found one of the rich needle was missing a seal. Don't know if it was enough to make a difference but I found a deep scratch on the tip where the fuel line attaches to the carb, so switch out the top of the carb for a back up I have.

 

Appreciate the feedback on the 123ign. Probably should've been more clear. @zinz installed the 123 and it was dialed in. So ruling that out for now. 

 

Will give it a try tomorrow. 

 

Thanks for the help!

 

[TobyB]

When you have a symptom of incorrect timing, it's always smart to check the timing.

 

With a light.

 

While running.

 

Because things happen.

 

But a cracked baseplate on the carb would certainly give you a gross air leak...

 

t

 

[Devilish_02]

2 hours ago, TobyB said:

When you have a symptom of incorrect timing, it's always smart to check the timing.

 

With a light.

 

While running.

 

Because things happen.

 

But a cracked baseplate on the carb would certainly give you a gross air leak...

 

t

 

Will do once I get it started 😀

[zinz]

I installed Jake's 123 a couple weeks ago.  We confirmed TDC and re-confirmed the ignition curve with an advancing timing light.  Unless the hold-down bolt/nut has become loose, timing should not be an issue. 

 

We then installed Barney's used, but good Solex 1 barrel a few days later. Engine was running nicely when we were done at that time.

 

The phenolic spacer getting cracked since then, must have caused the lean condition he's currently dealing with.

 

Ed Z

[Devilish_02]

Updated video. The backfiring hasn’t been as loud and for the most part has been at the muffler. I have confirmed that the spark plugs are getting a spark, the battery is fully charged, and have played with the idle and fuel mixture.

[Devilish_02]

@zinz reached out and solved the last piece of the puzzle. TDC was 180 off. Valuable newbie lesson. Really appreciate everyone’s help and advice. Pretty amazing.