Carb bow lament

Started carb rebuild.

Took off bowls and boiled them in lemon juice in a crock pot on high.

Used guitar strings to probe enrichment circuit passages.

Two of the bowls' enrichment sircuits cleaned up nicely with carb cleaner squirting a good distance just like the Youtube video.

One bowl has an anemic gurgle coming out of the enrichment passage.

The fourth bowl's enrichment circuit is stuck solid.

I used guitar strings from .020" to .045 inches. The amoung of string the passages is identical for all four bowls.

I am wondering if a piece of rust is stuck in the one bowl or if a PO shoved some vile tool into the passages of the stuck bowls.

I will probably use two bowls from the other set of carbs if I can't get the stuck bowls unstuck. This set of carbs ran great but did not start easily.

Recommendations welcomed.

 

The clogged enrichment ports contribute a lot to hard starting.

I got a fine drill from chacal that can blast through the worst of clogs.

How long did you heat them in lemon juice? Maybe a longer soak?

 

I heated them a couple of hours completely submerged in RealLemon juice.

What is the diameter of the drill bit?

 

about 15 thousandths

 

Seriously? 0.015" ?

I have some circuit board drill bits and the smallest one is 0.047" diameter.

How long is the drill portion? How do you not break it when using it?

 

Yup I went and Mic'd it to answer you. Tiniest drill I have ever seen. It is about 1.5 inches long and the drill part is about .5 inch. I put it in a pin vice and use it very carefully.

 

Never heard of a pin vice.
I will Google it.

Did the drill bit unstick your stuck enrichment wells?
Do you use cutting oil or graphite oil with it?

 

Half----now you know why I sell that drill bit to clean out those starter jets.....it's REALLY tiny and really hard to find in that length!

The .020" guitar string is TOO BIG......that translates into a .50mm diameter, and the starter jet is only .40mm diameter, and since you do not want to enlarge the jet (just clean it), you need something smaller than .40mm that is also "stiff" enough to push through varnished gas.

That .020" guitar string is too large, and is not even penetrating the jet opening.......

Although a pin vise can be used, they are rather expensive to purchase for this type of "one time only" use..........the drill bit is long enough to where you can grab the end of it with some needle-nose pliers and just "hand twist" it and it will cut through the hardended gunk.......one person actually super-gluied the shaft of the drill bit to a toothpick, and created their own "pin vice" in that manner, which I thought was pretty darned creative, and worked well, besides!

 

Yes opened the one that was really clogged just fine and cleared one that sputtered like you have. Used it dry. If you have an Exacto knife (the pen type handle) you can use it to hold the bit.

What I did was use the bit then spray with carb cleaner. Then repeat until it squirted well. I turned it into the jet carefully, I would imagine it is easy to break.

 

Final questions

Do you drill it out the entire 1/2" past where the "shoulder" of the well is?

Chacal, how much is the drill bit?

I do have some 0.012" guitar strings. I will try to probe with one of those to see if I can get 1/2" past the well shoulder.

Thanks guys.

 

Half, just get a strong flashlight (LED "penlights" work well for this task) and you'll be able to sneak a peak down in there and see the jet.....it's actually about 1-1/2" down into the well shaft, which is why you have to use needlenose pliers (or "weld" an extension "toothpick" onto it, to grab the top of the bit which is just barely sticking out of the top of the shaft). If you have some .012" stiff wire that should do the trick...just push and twist.......if you have a file, "sharpen" the probe tip of the wire to as sharp a point as possible. It helps if you leave some carb cleaner or other type solvent in the well overnight to soften up the varnish as much as possible. The drill bit is $ 11.95 plus shipping.

 

Sorry for an additional question but what is the diameter of the drill bit shaft?

 

Couple of updates.

Never trust a Harbor Freight Digital Caliper for micrometer measurements.
I have a set of Printed Circuit Drills. The smallest is #78.
The digital caliper says that the bit is 0.046"
An Ebay seller with a set of 10 drill bits says that #78 is 0.016"

I happen to have an antique micrometer.
The mic says that, yep, the bit is 0.016"

A few minutes with this drill bit and YIPEE I can see light with an LED penlight.

 

Cool -but interesting my mic is a Harbor Freight

 

Sounds like somebody maybe dropped his caliper?

Can you say, "Warranty!"?

 

for what it's worth my enrichment circuits opened up after switching from gumout to chemtool!