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The needle tip on this 1925 Evinrude Elto RBM, Model “C”.
poppet valve carb, is in bad shape.
The needle has 10-24 threads that screw into
the carb body, so it’s not real “hefty”.I’d like to attempt to make a new one. I don’t have any 10-24
bolts long enough (1-1/2″) to make a needle from, so would
have to use rounds stock of some kind.The original needle is steel. Any reason brass wouldn’t work okay?
It’s a pretty “pointy” needle tip. I have my doubts about turning the tip
on my lathe with a tool bit. I was wondering how a dremel set up in
the lathe tool post, using a stone to grind the tip would work out?
Steel might be better in the later case, as brass would probably plug
up the stone.Any suggestions, better ideas, etc, appreciated. Thanks.
Also, that stiff little spring noted was inside the poppet valve cover,
used for a “stopper” for the poppet valve. Is that original, or should
if have cork, etc., in it?
Prepare to be boarded!
The needle in your phots should be fairly easy to make if you have some 3/16 stock or an extra OMC coil screw on hand although the coil screw might be too hard. As mentioned, after setting up to copy the original taper, super light cuts with a sharp bit or insert will give you a fine point. Here’s where a set of collets do come in handy as using one will give better accuracy and you wont have spinning jaws trying to grab your slides or tool post!
Here’s a couple needles I made, one for a Koban and one for a Thor mixer. A straight knurler was used on the Thor adjusting knob while I was able to salvage the original one for the Koban. The original Thor needle was missing so I had to guess what the original looked like and its dimensions.
I made a replacement needle, and the blow test with the needle seated seems to indicate that it will work.
I was able to use 3/16″ 5C collet in the lathe, even though the stock was .025 larger.
The closest I could measure the old rusty needle was an included angle of 18 degrees,
so that’s what I made the new one.I turned down the needle point to about 95% finished, then was having some trouble getting
the bit to “cut into” the pointy end. Perhaps a little deflection in the point.
Therefore I switched over to a Dremel and stone mounted on my tool post.
That seemed to put a pretty nice finish on it, but I polished it up a little with
steel wool too.
Prepare to be boarded!
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