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Engine basics => Engine set up tips => Topic started by: Robert McHam on February 25, 2008, 04:02:18 PM
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I just got a used Wen-Mac Mk II and I discovered right away that the needle valve has broken off . I thought at first glance it was removed for shipping for the spring and nv were loose in the ziplock baggy. A second later I was thinking how short the nv was and that there was no "point" (needle) on the end. Another two seconds later I was staring at what I hoped would be an empty hole where the nv was supposed to go and sure enough, I found the rest of the nv. Flush with the opening I have no idea How to back that tiny thing out.
I do have a pin vise and some bits that are quite small but I'd be wishing for a left hand bit to possibly do the job. A standard bit might only seek to go farther inn the hole and possible seat itself tight.
Keep in mind I live in an apartment and have but a few hand tools and my Dremel and a cordless drill to work with. No shop available.
Also does anyone have a Replacement nv should I be able to somehow remove the offending blockage?
Robert
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Find a dental pick type of tool. If you pick at the broken off part, you can very likely get it to turn. If it doesn't move, try acetone, lacquer thinner, mild heat, etc. If all else fails, look for a gunsmith. Those guys are good at removing small screws from expensive items and he might even do it for free, just for the fun of it.
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You might try slotting the broken end with a needle file. Also, drive a piece of fine steel tubing over the tip of the needle, coming in from the fuel line end. Russell has it right, alternate heat and sok with penetrating oil for at least a couple of days. Then clamp the spraybar off the threads, and torque the needle from both ends at the same time. Tom H.
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Woo Hoo! Thanks Russell! the dental pick did the job.
You would be surprised at how few the number of tools that I do have yet I have found my cheapo pick set indispensible at times.
The break was fortunately rough and gave me just a little to get it turning. No heat or solvents required. It was painfully slow (in my estimation) but I saw tiny positive results almost from the beginning.
Bottom line: it is completely out and no farther damage to the engine and i have the satisfaction of getting the job done myself.
As for the gunsmith idea I do know someone who has a son that is quite an accomplished gunsmith I have been told.
That being said, another idea might be a watch maker. I would not thought of that had the gunsmith not been brought up.
Thanks bunches, Robert
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You might try slotting the broken end with a needle file. Also, drive a piece of fine steel tubing over the tip of the needle, coming in from the fuel line end. Russell has it right, alternate heat and sok with penetrating oil for at least a couple of days. Then clamp the spraybar off the threads, and torque the needle from both ends at the same time. Tom H.
Tom, I did think of slotting but the part was recessed and would have had to cut into the outer part to do so. Even if it weren't recessed the mounting lug and cylinder are too close to allow even a needle file more than a quarter of an inch travel.
The tiny tubing idea sounds good if I could find one with an O D of about 1/32" or less. Maybe a hypodermic needle with the sharp point ground off? That might have worked going through the tiny fuel nipple.
Robert
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I learned that trick from a gunsmith friend. Works for broken Stunt 35 needles, too.