won't start

Lost power around 40mph

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white1j0
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won't start

#1

Post by white1j0 » Sat Sep 22, 2018 5:37 pm

Finally took my '47 Knuckle out for a longer ride about 35 miles, rather then around the block trying to get used to a tank shifter, about 2 miles from home it started to spit and sputter I was doing about 40 mph, then it conked out, had to trailer it back home, I've been trying to get it started for the past 3 days, all it does is backfire through the carb, the motor is completely rebuilt including the M-35 Likert, and the generator, I have good spark, and it's getting gas, up until this it was running like a watch, 2 primer kicks and it would fire, when it was warm it started every time 1 kick,also no manifold leaks, and plenty of compression, any suggestions, Thanks Whitey



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Re: won't start

#2

Post by RUBONE » Sat Sep 22, 2018 6:59 pm

Points closed up?

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Re: won't start

#3

Post by Pete808 » Sat Sep 22, 2018 7:27 pm

I just had the same exact thing happen to me on my FLH this week. It took me 3 or 4 days of trying to figure it out, drove me nuts. I changed the condenser once it started sputtering and back firing, my float was also way off so I adjusted that. Not sure which one was the issue or a combination of both but now it is running great again. At the same time I changed and re-gapped my points as well.

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Re: won't start

#4

Post by Buddhahoodvatoloco » Sat Sep 22, 2018 8:40 pm

If its still 6volt, your battery probably dead. Plus as has been mentioned, points, take the cap off and kick in the dark, once the battery is up to snuff.

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Re: won't star,

#5

Post by Andygears » Sun Sep 23, 2018 9:34 am

Fuel? Are you sure? Splash some gas in the carb mouth and try. Two miles is enough to break junk loose and clog up the line or inlet valve or filter. And sputter, cough, die usually sounds like fuel delivery.

My two cents
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Re: won't start

#6

Post by white1j0 » Sun Sep 23, 2018 2:11 pm

I rechecked the points and found they closed up they were at .008,I reset them at .022 made no difference in trying to start, set timing mark in timing window, front piston up, then checked my points and realized somehow my timer jumped a tooth, points were off about 90 degrees, pulled the timer and reset it, the engine start and runs rough like its running out of fuel but conks out immediately, I was thinking one of the cam cover bushings might have disintegrated causing it to jump timing.

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Re: won't start

#7

Post by Buddhahoodvatoloco » Sun Sep 23, 2018 3:12 pm

Wow, that does not read promising at all, but on these pups it's all doable.
white1j0 wrote:
Sun Sep 23, 2018 2:11 pm
I rechecked the points and found they closed up they were at .008,I reset them at .022 made no difference in trying to start, set timing mark in timing window, front piston up, then checked my points and realized somehow my timer jumped a tooth, points were off about 90 degrees, pulled the timer and reset it, the engine start and runs rough like its running out of fuel but conks out immediately, I was thinking one of the cam cover bushings might have disintegrated causing it to jump timing.

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Re: won't start

#8

Post by RUBONE » Sun Sep 23, 2018 3:55 pm

I think you screwed up your timing. Make sure the timing mark is front cylinder on compression stroke. The piston is up twice per cycle so just checking the piston position is not the way to tell. Make sure the mark comes into the window just after the intake pushrod closes. Timers don't jump teeth. The only thing would be if the pin sheared on the gear, but that is extremely rare. And a bushing disintegrating would be a first.

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Re: won't start

#9

Post by Buddhahoodvatoloco » Sun Sep 23, 2018 4:40 pm

What was written previously has validity, this is what I found one time in the cam chest cavity..
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Re: won't start

#10

Post by white1j0 » Sun Sep 23, 2018 9:42 pm

RUBONE wrote:
Sun Sep 23, 2018 3:55 pm
I think you screwed up your timing. Make sure the timing mark is front cylinder on compression stroke. The piston is up twice per cycle so just checking the piston position is not the way to tell. Make sure the mark comes into the window just after the intake pushrod closes. Timers don't jump teeth. The only thing would be if the pin sheared on the gear, but that is extremely rare. And a bushing disintegrating would be a first.
Rechecked everything, Front piston about 1/2" tdc intake / exhaust valves closed, timer mark just coming in window, points just getting ready to break.
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Re: won't start

#11

Post by PanPal » Sun Sep 23, 2018 11:29 pm

Circuit breaker fully advanced? Do the points stay closed as you retard the timing?

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Re: won't start

#12

Post by white1j0 » Mon Sep 24, 2018 9:44 pm

PanPal wrote:
Sun Sep 23, 2018 11:29 pm
Circuit breaker fully advanced? Do the points stay closed as you retard the timing?
Points are working fine, changed the condenser with a new Blue Streak I had laying around, pulled the cam cover everything is as new, starting to think its the coil, what are the signs of a bad coil ???,

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Re: won't start

#13

Post by Andygears » Tue Sep 25, 2018 12:08 am

So it will now start but run very rough? How do the plugs look? Black, wet or dry, white, light brown.? I still think fuel delivery but maybe plug wires? Is it running rough...missing randomly or really weak on one cylinder rough, check for difference in temp. Between the cylinders. Or running rough from extra rich, float and/or needle sticking, or rubber tipped inlet needle disconnected from needle body causing intermittent lean.
Picture of the spark plugs please.

Andygears

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Re: won't start

#14

Post by white1j0 » Tue Sep 25, 2018 1:43 pm

Andygears wrote:
Tue Sep 25, 2018 12:08 am
So it will now start but run very rough? How do the plugs look? Black, wet or dry, white, light brown.? I still think fuel delivery but maybe plug wires? Is it running rough...missing randomly or really weak on one cylinder rough, check for difference in temp. Between the cylinders. Or running rough from extra rich, float and/or needle sticking, or rubber tipped inlet needle disconnected from needle body causing intermittent lean.
Picture of the spark plugs please.

Andygears
Does not start, just backfires through the carb, plugs are burning just a slight bit rich. Going to switch coils from my other '47 today and see if that's the problem.

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Re: won't start

#15

Post by guppymech » Thu Sep 27, 2018 3:58 am

white1j0 wrote:
Mon Sep 24, 2018 9:44 pm
PanPal wrote:
Sun Sep 23, 2018 11:29 pm
Circuit breaker fully advanced? Do the points stay closed as you retard the timing?
Points are working fine, changed the condenser with a new Blue Streak I had laying around, pulled the cam cover everything is as new, starting to think its the coil, what are the signs of a bad coil ???,
A bad coil will have difficulty producing a spark under cylinder compression but will show a spark with the plug out of the cylinder. If you have a inductive timing light you can use it to see if the plug is firing when it's installed, a bad coil won't cause the timing light to flash.

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