1. Home
  2. ⏣ General Metalworking
  3. Making a float chamber fuel level needle

Making a float chamber fuel level needle

This is an old small 2 stroke mower engine with a worn out float chamber needle. A mfg. replacement is not available. I turned one up out of nylon which works but obviously allows leakage as the fuel tank level is critical! and floods when stationary for any length of time. The original (silver alloy? ) needle had what looks like a neoprene tip 60 deg included angle that gave way a bit as it entered the fuel supply hole and made a proper seal with the float pressure available. I am trying to bodge up a precision tip from a bit of O ring but getting a fixing to the body of the needle is a problem as any glue will be in a really melty envionment (fuel/oil mix). Any one else been down this path with a solution?! The widest part of the tip is 2.5mm to give some idea of scale. My nylon body works well for the larger part and doesnt wear out the barrel it slides in. Oh and of course all this lives in a very vibrating chamber! Charlie+

Reply to
Charlie+
Loading thread data ...

Perhaps you might try a different approach; there are auto carburettor needle valves on some older model vehicles which may be able to be modified for your purpose. Some Bendix - GM models of the 70's come to mind, complete wirh neoprene tip.

Reply to
Chas

Why make something that can be easily adapted from another vehicle? Carburetor needle valves are cheap, find one close and fit your carb to it.

Reply to
RB

Any chance you could use a metal needle part and counterbore the fuel inlet to hold a tiny o-ring or maybe just a piece of neoprene with a small hole through it?

Jeff

Reply to
Jeff Wisnia

Charlie, Don't reinvent the wheel...........go to a carb shop and they will probably give you one. If it doesn't exactly fit, make it fit. Steve

Reply to
Steve Lusardi

Many carburetors use a soft tipped needle. Some small engine carburetors use a hard needle with a soft seat insert. Someone at a small engine or carburetor shop should be able to find something that will work with little or no modification.

Don Young

Reply to
Don Young

On Tue, 17 Mar 2009 16:22:24 -0400, Jeff Wisnia :

Now that is an interesting workaround! Thanks Jeff . Thanks to others who replied also. Yesterday evening I made the tip out of a bit of O ring as planned and mounted it mechanically on a 1mm dia. brass panel pin head and ground to shape, and that has the engine working perfectly, however longevity is another matter - I wait and see - ! Charlie+

Reply to
Charlie+

There are zillions of automotive carb needles, many of which you prolly could adapt. Trouble is, there are not many carbed cars around, and most repair shops, which would have lots of carb parts 20 years ago, prolly don't even know how to rebuild one anymore.. Napa might have a selection of needles only by application. Or a speed shop. JR Dweller in the cellar

Charlie+ wrote:

Reply to
JR North

Brass is your friend. Viton tipped needles are a recent phenomenon. Brass and aluminum were used for years - or steel with a fiber or nylon or rubber seat. Look at a Tecumseh or Briggs float valve to see what I mean. Might be able to convert the carb to use one of them.

Reply to
clare

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.