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Flame out at idle.

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Kicker42

Member
Have a 70 shovelhead FX kicker only, that will flameout at idle with hot or cold engine, then will not restart.
Runs all day without a hiccup on road. Have Mallory Pointless ignition, RevTec Hi Performance coil, S&S E carb, new wires and e3 spark plugs, new battery, etc. Not sure of coil ohm value... or whether or not the Mallory ignition is considered electronic... Can anyone give me a clue to solving this flameout problem. This has been ongoing since I first built her in 2002. Everything including motor has been rebuilt or replaced including exhaust pipes. Just unsure about coil.
 
tourbox said:
Welcome from So. Texas. What do you mean by Flame out? It just dies at Idle?
tourbox
Click to expand...
Yes it dies at an idle, cold or hot. Some times there is a pop like sound and others it just quits in an instant. Then it won't restart with kicker but it may restart by bump start in second gear.

Yes, it just dies at an idle. Hot or cold. Some times it goes out with a small pop, other with a hiccup. Won't restart by kicking for at least 30 kicks but may start by bump in second gear.
 
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First do you know what your Idle rpm is? It should be about 900-1000 rpm. Next do you know which Mallory unit you have? There is a difference for mechanical advance versus the cup/rotor advance. The A554 unit is for mechanical advance but can be used in '79 and later units if converted back to mechanical adv.. Being yours is a '70 model I assume it's still mechanical advance. Your coil is as following per Mallory's instruction sheet for the A554;
What is the primary resistance of the coil? It should be at least
2.0 ohms for racing and at least 3.0 for street use.
Off hand I would lean toward the Idle rpm's due to your statement " Runs all day without a hiccup on road".
You can go to https://www.msdperformance.com/ for more info.
tourbox
 
You should also check you Idle/Air adjustment screw on the S&S Super E after good warm up.
tourbox
 
Hi Tourbox. Just fot the record, im old school with limited gray matter. JUST GRAY HAIR. My AnnaG (shovel) has a dual fire Mallory with mechanical advance. Just looked it up. The current book i just looked at showes it requires 3 to 4 ohm coil. I will try to figure out the resistance of my current coil. My current idle rpms is 1000 at running temp and 800-900 cold. Some background...I first built AnnaG from all used parts in 2002. Found motor then frame front end then wheels fenders, on an on. My mom gave me $200 to get her started. Inital motor titled as 1978 but when tore down showed 70 fx crank for external distributer but now has cone head distributor. This motor was assembled in late 70 (begining AMF years) and sold in late 78 (begining HD restoration years). She was pumped up for racing with hi performance heads, big valves, dual plugs, electronic ignition, etc.. I left the maxed out jugs, went back to point's then to Mallory ingn, stock s&s heads with single plugs, stock valves, stock 7x1 compression. She retains the Wisco hi dome pistions, cylinders at max bore, top end cam (unknown grind), stock cycle shack pipes with baffels bored straight through, s&s E carb jeted to .072. She runs strong but "never" idled witout flame out.
Hope this may provide further insite. I haven't given up and know someone out there has the correct answer.
Ill try to get coil resistance.
 
Thank you.

The s&s E replaced the stock Kien carb. The Kien carb provided 0 response compared to the E. The new E carb change did nothing to correct flameout. She just ran stronger but still pooped out at idle.
Changing pipes and increasing back pressure seemed to some what improve the problem but not repair problem.

I stopped in at s&s in Sturgis SD a while bsck and again in Laughlin NV. I set air and main jets to their specs to no availe. The problem persist.

Thanks guys. I will try to test this existing coil for its condition. Not sure of procedure as yet. I do have s meter.
 
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You test it with a Volt Ohm meter. Set meter to lowest Ohm setting. Measure across the 2 small lugs that are for +12Vdc and your Mallory wire that attach to the coil. Also check your timing with a light. You may need to advance it a tad due to motor hop up. Also while checking timing check your mechanical for free movement. It should easily rotate left(counter clockwise) then spring back quickly to the right(clockwise) when released.
tourbox
 
Hello again, with an update. I have had a lot of good input from this forum and hd forum that hit home. Here are the results. The coil checks out ok at 5.1 ohms and the Mallory ign. specs calls for 3-4 ohms according to parts book. Will look further into this. I had recently updated the main jet to .072 because pipes look lean but reset it to .068 with good results. I also removed un needed in line filter from fuel line that cause this problem too. Lastly I checked the right vented fuel cap and found an obstacle like a spider blocking the vent. According to input, all these problems caused the flame out or missing at an idle. AnnaG now seems to idle just fine. But the jet change also changed the kick start sequence that I Will have to work on. Good work. M thanks to all of your valuable input. Kindly, Kicker42
 
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