Logo

Early 70bs johson 25 hp carb is it missing a part

jon

Regular Contributor
" Hi,
The adjusting nee


" Hi,
The adjusting needle on my early 70's 25 hp johnson is a fairly long (3 inches or so) shaft with a point on one end, and a cap (has a lever on it) on the other. It sits inside of a hollow cylinder, which is threaded on the outside, and has a hex head on the end. Inside of the hole that all this slides into (looking down into the carb) there was a gasket that this needle threaded into.. I took it apart to rebuilt it, took out the gasket, and then tried to re-assemble it later using something I retro-fitted, and it wouldn't thread, the threads did feel funny when I was taking it apart.. but then I realized the gasket was holding it in.. is this right? Or does anyone know if I'm missing some type of threaded cylinder that this needle grabs on? Does the rebuilt kit come with this gasket? "
 
"Jon.... I don't know if y

"Jon.... I don't know if you're saying that the slow speed needle valve falls into that chamber, or if it simply won't thread into it properly, such as being cross threaded. At any rate, down inside that chamber is a aluminum barrel like
sleeve that's threaded inside to accept the slow speed needle valve. It's just slightly smaller in diameter of course to fit inside that chamber, and it is about 1/2" long.

There are two (sometimes three) packing washers that go between that brass hex headed jam nut and the carb, the purpose of which is to (as you tighten the jam nut) secure the needle valve to keep it from moving due to vibration. If you have a problem finding those packing washers, send me a stamped self addressed envelope and a couple dollars and I'll send you a few. The part number is (OMC) #307583.

And just for the record, those brass hex headed slow speed type jam nuts were last used in 1968. What is the model number on your engine?

Joe
"
 
" Joe,
Thanks for the q


" Joe,
Thanks for the quick reply.. well, from what you've said allready I know what the BIG problem here is.. that sleeve you are talking about is missing.. the packing washers were holding the needle in, which is why the threads fealt so wierd, and explains my confusion about how packing material could possibly be used to hold the needle in.. it can't and doesn't, and is probably why my carb stopped working right in the first place..

I'll grab some numbers for you, but this motor is something I bought off one of the local part swappers - it's totally possible that the carb is from a different year than the powerhead, which is probably a different year than the exhaust housing and lower end. If you do have a couple of packing washers and the threaded cylinder that appears to be missing, get me the address to mail this to and how much you want for the parts, thanks Joe

Jon "
 
Back
Top