Skip to main content

Posting this twice. General and technical.

I have been dialing in my Webers and working on the 3 - 4k range with the main jets. Having success too.

But last time I put in the emulsion tube #4,  out of the corner of my eye I saw a flash of brass. Yep - the main jet had fallen off the tube. (I was sure it had a tight pressure fit, but ...noooo.)

So I took my mirror and flashlight and could not see it anywhere. I thought it had fallen down the venturi - but not completely sure. 

So next I put a light vise grip on the throttle arm so the throttle plate would not open sending the jet into the cylinder, then proceeded to disassemble.

Step by step , all the way down to the intake manifold, I could not find that blasted jet.
So now I am thinking the worse, some how it made it's way into the cylinder 
(fiy - I meticulously cleaned the engine compartment, and I looked everywhere (Everywhere!) before beginning all this.) 

With mirror and flashlight I can not find the bugger. So now I rotate the engine until the pistons are at their top , still not see or feel anything. So I take a pencil and stick it down #3 and #4 when each is at it's top to see if I can feel / hear anything. Nope. 

Next  I take a shop vac and stick it on cylinders to try and vacuum it out. Nothing. Then I thought better of this , because I got a visual image of me blowing up my garage. (electric spark + gas vapors = dead Carlos)

Then I rotated the engine around a few times via the crank . Did not feel or hear anything.

At this point I am thinking it is simply hidden somewhere in the engine tin or compartment where I could not find it. I reassembled everything, but before cranking wanted advice.

If the jet is in the cylinder , would I feel it by hand rotating the engine like I did? Would the cylinder even make it to the top of it's stroke? Could the jet keep me from being able to rotate the engine?  What happens  if it is in the cylinder, and I crank it - lunch the engine?

Before I turn bad luck into something stupid, I thought I would ask for some advice. Help.


Original Post

Replies sorted oldest to newest

Well that all depends, there is a small space on the cylinder head tins were it could make it by and resting on top of the cylinder or along side of a spark plug head fins. I don't see how something that big i.e. the  jet,  if it could make it's way into the cylinder you may have enough clearance ( dished head) when you rotating it by hand having clearance  at TDC... BUT with the engine running and the valves going in and out of the head it could turn ugly. How about a bore scope ?   See attached photo, this was caused by a tiny piece of carb casting.




Images (1)
  • 20190601_161712
Last edited by Alan Merklin

Dude, I'm really sorry. I've gone through similar things.

It's not down the cylinder. The throttle plates were closed when you dropped it, and you were super careful not to open them when you did everything else.

$10 says it fell down beside the intake, and is laying in a cooling fin somewhere you'll never see it without taking the engine apart. Just be super careful when you take out the plugs next time.

Wow, dude - I am sorry that my sparkling personality and ‘Murphy’-like luck is rubbing off on you. For example: I could drop my toothbrush upstairs in the master bathroom only to eventually find it months later wedged down in the bowels of the doghouse of my Speedy theoretically parked ‘safely’ in the garage!!!

I’m with SactoMitch: buy a new jet and the one you accidentally dropped and can’t find will turn up immediately!! Hang in there!!

Add Reply

Post Content
Link copied to your clipboard.