Can Float Adjustment Be a Source of Running Rich?

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tcb-1
Posts: 106
Joined: Sun Sep 11, 2011 12:06 am
Bikes: 1950 FL

Can Float Adjustment Be a Source of Running Rich?

#1

Post by tcb-1 » Tue Jan 31, 2012 2:26 am

I think I know the answer, I believe it's yes. But really how much can a float be off to cause a rich mixture? On idle, I'm blowing a bit of black smoke still after a good warm up, and the spark has been advanced...... and my gas mileage absolutely sucks (literally).

Everything else checks out, my Linkert is set to factory specs, good compression, hot spark, good fuel and flow, Autolite plugs gapped correctly.

I'm down to the float. I read several past threads that Cotten had went into detail of what a too high of float could cause. Before I drop the bowl and readjust, I'd like the expert's input.

THANKS!!!



Cotten
Posts: 6791
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois

Re: Can Float Adjustment Be a Source of Running Rich?

#2

Post by Cotten » Tue Jan 31, 2012 4:09 am

tcb-1!

I do remember declaring that there is only one setting by the book: 1/4"

If the float is not buoyant enough, then the level of fuel in the bowl will indeed cause enrichening, so one must have a float that floats.

What sort of float do you have?

Heavy floats can be made to work marginally, but they must be set much deeper than scriptures order, and precisely only by trial and error.
Light floats make the sensitivity issue drop out of the equation, as you may notice that in Service Manual instructons that side-bowl models with no gasket were spec'd at the same setting as OHV inline bowls with a gasket.
So a ruler is overkill for measuring. Square to the top is the hard part.

Even with a buoyant float, a carb will require to be set overly rich if there is a vacuum leak;
Have you bubbletested your manifold assembly?

...Cotten

tcb-1
Posts: 106
Joined: Sun Sep 11, 2011 12:06 am
Bikes: 1950 FL

Re: Can Float Adjustment Be a Source of Running Rich?

#3

Post by tcb-1 » Tue Jan 31, 2012 4:25 am

Cotten,
Kind of embarrassed to say, but my float is more than likely the one that came from Milwaukee in 1950. :( Maybe it's time for a replacement.....

However on a curious note, when adjusting the low speed needle, I have to turn it completely in. If I set it any further out, say a full two turns, it loads up more than normal. Can an issue with the low speed needle be causing a rich mixture?

I had to laugh about what you said about using a ruler to check the float level. That's exactly what I did, and I don't know how many times I tweaked the float tab before it was absolutely set to the book. I may have been a bit too particular?

Looks like a bubble test of the manifold is in order, since I haven't done that yet.

Cotten
Posts: 6791
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois

Re: Can Float Adjustment Be a Source of Running Rich?

#4

Post by Cotten » Tue Jan 31, 2012 3:00 pm

tcb-1!

If your float is cork, it may indeed be logged and losing its buoyancy.
If your float is an OEM black "Armstrong" of the '50s and '60's, then it may swell, leaning the mixture slightly before it finally rubs the bowl or bowlstem, and overflows.

Your LS needle length, point, and knob spring should be inspected, as well as additive wear upon the liftlever and chokecam, and even the chokeshaft bore in the body,...
and the LS spring collar seat... etc.,

...but tuning may be greatly changed if a vacuum leak is found and remedied.

Let us know what you find,

....Cotten

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