Won't prime

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white1j0
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Won't prime

#1

Post by white1j0 »

I'm having a hard time getting my Panhead carb to prime, I either have to kick it over about 25 to 30 times at the minimum, or manually prime it with a spray bottle, it never floods and the plugs are always bone dry, when it starts it runs perfect, and I can restart it with one kick, or even 4 or 5 hours later one kick and it starts, but the next day back to square one, any suggestions would be greatly appreciated.
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Re: Won't prime

#2

Post by mik666 »

sounds like a small manifold leak to me - when everything is warm it seals up but when cools down leaks a bit
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Re: Won't prime

#3

Post by RUBONE »

What is your priming technique?
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Re: Won't prime

#4

Post by white1j0 »

I had a manifold leak, but I repaired it, I've tested it quite a few times and no leaks, I usually kick it three times w/choke and throttle closed then one click down on choke.
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Re: Won't prime

#5

Post by RUBONE »

Priming is performed with the throttle wide open.

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Re: Won't prime

#6

Post by white1j0 »

Been trying it both ways throttle open and closed, doesn't make any difference, been kicking it and priming it all day, finally shot two squirts of gas down the throat and started right up.
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Re: Won't prime

#7

Post by RUBONE »

Does it have any cranking compression? What cam is in it? Big overlap = no cranking compression...so no vacuum draw.
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Re: Won't prime

#8

Post by Scrap »

RUBONE wrote: Thu Aug 16, 2018 11:55 pm Priming is performed with the throttle wide open.
Have I been doing something wrong all these years?
The link to the hd manual starting instructions says to advance the spark before kicking? Wouldn't that cause kickback? Have i been setting the timing wrong all this time?
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Re: Won't prime

#9

Post by blewcrab »

how about checking the float level …..maybe it not filling enough....jus a guess
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Re: Won't prime

#10

Post by RooDog »

Let's not assume anything here, what carb are you using?
And, If you try to kick it in the fully advanced position and I does not kick back I would think the timing is off. The reason for the retard on both our Harleys and electric start bikes, and even cars too, is to prevent kick back from ruining knees and starter bendix drives....
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Re: Won't prime

#11

Post by white1j0 »

RUBONE wrote: Fri Aug 17, 2018 1:56 am Does it have any cranking compression? What cam is in it? Big overlap = no cranking compression...so no vacuum draw.
I checked the compression and it has only around 45psi, then I checked my Knuckle, and it only has 90psi, then I checked my Fatboy and it only has 90psi, I don't know what cam it has in it because the motor was rebuilt when I bought it, has less then 200 miles on it., the Knuckle has a stock cam and that motor I had had rebuilt, has less then 100 miles on it. also it's a HF compression tester and might not be accurate, It's a '52 motor has a Linkert M74B carb, completely rebuilt w/ a Rubber Ducky Float, float set at 1/4", also I always retard the timing, when cold, too old to have another broken foot.
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Re: Won't prime

#12

Post by RooDog »

That compression number sounds quite low. Do you have the throttle wide open when doing the comp test? Otherwise you are pulling a vacuum and not getting a true reading. Remember that engine is basically an air pump so don't restrict the air flow it is trying to pump...
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Re: Won't prime

#13

Post by Mark44 »

Scrap wrote: Fri Aug 17, 2018 3:05 am
RUBONE wrote: Thu Aug 16, 2018 11:55 pm Priming is performed with the throttle wide open.
Have I been doing something wrong all these years?
The link to the hd manual starting instructions says to advance the spark before kicking? Wouldn't that cause kickback? Have i been setting the timing wrong all this time?
Sam
The text in the Service Manual says "Spark should be fully advanced or nearly so."
The "fully advanced" part looks to me to be an error that wasn't caught before the manual was published. Anyone who has a kick-only Harley knows the danger of trying to start the machine with the timing at full advance.
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Re: Won't prime

#14

Post by Mark44 »

45 psi seems very low to me -- possibly the rings haven't fully seated yet? If you squirt some oil into the cylinders on a cold engine, does the compression rise?

Regarding the carb, one possibility is that the low speed needle is set too lean. Try turning the knob on the low speed needle out (counterclockwise) a couple of clicks, and see if that makes a difference. An overlean condition would have more of an effect when you're starting a cold engine than when it's already warm.
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Re: Won't prime

#15

Post by Andygears »

When the Linkert was rebuilt, you didn't use a float needle with a rubber (neoprene?) tip that can stick in the hole until the bike starts and shakes it loose? Just a thought.

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