Ignition problem?

[EricS]

We went in the alps this week-end for a show. Car went fine on friday and saturday.
On returning on sunday, it started developping a problem. When pulling on the throttle other than really gently, it seems to suffocate and makes somes bangs.
Worst up hill, still present on flat or down hill where it needs more throttle to makes it.
Only when engine is loaded. No problem at neutral or park.
Ignition module well plugged in, vacuum hose from distributor to carb well there. I re-routed it above the coil as I thought it might be too close to the engine !?

I thought it might be the altitude (1600m/5200ft) but it still does it at 1000ft.

Any idea?

[LaOtto70Charger]

Did the timing change some or choke sticking?

[EricS]

Well choke is not sticking and opens wide. I have been told today it might be the carburetor accelerator pump diaphragm. What carburetor is it?

[LaOtto70Charger]

Can you post a picture of it? There should be a name on the outside if aftermarket replacement. What engine size?

[A383Wing]

almost sounds like a bad coil

[b5blue]

Similar to when my Firecore Dist. failed.

[EricS]

Here are pictures for my carburetor.
The white label seems to indicate that it has been re"manufactured" in 2008 by BREMCO?? Sounds possible as PARKER went out of business sin 1985
What model is it then?

[LaOtto70Charger]

That is a carter carb.  I think the accelerator pump is on the front part on top, but it looks different from my old 2 barrel one off my 70 with a 318.  Not sure how good the pumps are in carter's.  I think hollers were the ones that would seem to have issues with them after a backfire through the carb..

Do you have a voltmeter or timing light? There is some good instructions on checking the coil resistance with a voltmeter if you use the search feature on this website.  Or you could try a new one after making sure the connections are good. 

If you have a timing light you can check the base timing at idle but also as you increase engine speed using the throttle linkage.  My old points distributor had stuck weights and wouldn't increase timing with engine speed. I was running an electronic pertonix distributor recently that kept backfiring through the carb when the engine was cold and taking off from a stop. 

From what the others stated I would start with ignition also.

[EricS]

I checked the accelerator pump from instructions on Mike's carburetor website and I have well the jets spitting carb in the barrels. So I would lean toward exonerating the carb.
Will try another coil first.

[AZMoparboy]

Now I don't have the history of working on cars  🚗 as most of you do, but I've found out in my 40 plus years of an aircraft mechanic that a lot of problems should be approach at all of the most simple things first. I like what the others have said about the ignition system. Some years ago I had a similar situation in a hard acceleration my 440 would hesitate and actually seemed like it was even not running while accelerating hard. While looking for a cause I found the coil + connector with one strand of the wire holding on. When I found it the engine was running, I wiggled  the wire completely broke and the engine stopped running. I fixed the wire and no more hesitation. It was such a simple fix. Just my 2  on approaching a problem. I do hope you find the problem easily, good luck.

Azmoparboy
Steve

[GreenMachine]

Check the wires to the pickup coil inside the distributor. Look closely, sometimes they get brittle or even interfere with the advance mechanism.