Single HS2 on an 850 Mini Moke acting odd

[pbraun]

This 850 Mini Moke has sat for a few months only. Only reason I started messing with it was a stuck jet valve in the float bowl, so no fuel & wouldn
t start. Now it seems to have a sort of floating needle, as it wobbles with the needle screw in or out, tight or loose. Plus I can't remove it, even after multiple cleanings and soaking in PB Blaster penetrating oil.
The motor starts, but revs up quite a bit, then dies. The jet is up to even with the carb, choke is working fine. Float bowl fine and feeding gas. The carb was working fine a few months ago. I changed the gas and filter also.
So here's a pic of the piston and needle. Anyone have any ideas on this? I did find another HS2 that looks similar to this one, but doesn't have a wobbly needle. I have not tried swapping pistons, the older one is clearly much shorter.
I'll put some pics here.
Original piston/needle on left, shows holes, with wiggly needle, looks like 2 pics of same.
Here are top view, showing the older piston on the bottom, then on the right. I am open to any sugggestions.

 

[pbraun]

I have found out the "floating" needle is correctly called a bias or swing needle. Doesn't help me now as the 850 won't run long enough to warm up. Still don't know what to do. The bias needle was running. The older carb has a fixed needle.
I will now look up the correct needle to have for a stock 850, if I can find it somewhere. I feel rather dumb here.

 

[DrEntropy]

Put the carb back together and check fuel delivery TO the carb. That needle is not the problem. This sounds like a supply issue.

Far less likely but possible is a coil failing as it gets hotter.

 

[pbraun]

Replaced fuel jet in float bowl. Was previously stuck, now ok. I will pull the float bowl cover to check.
Getting spark. ???

 

[pbraun]

Today is a rest day for me, with a good cigar. Then i will check all the ignition, and fuel delivery. It's got to be one simple thing or t'other!

 

[LarryK]

I always find problems are mostly simple. Just over thought and rushed. Good luck.

 

[Scargo]

Peter,

The correct needle for an 850 Moke would be a fixed needle in one of the the following three profiles:

GG - lean
EB - standard
M - rich

Since you changed the float bowl valve, make sure to check the fuel level in the bowl, and adjust it as needed.

Also, if you end up changing the piston, you should also change the suction chamber (dashpot), using the one that came with that piston,. to avoid a mismatch.

Where do you have the jet locking nut set ie: how many flats down?

Have you checked for vacuum leaks?

 

[pbraun]

Yes Howard, have done all that - planning to go back and check it all . The jet nut only a few flats down.
Have any extra EB needles?

 

[Scargo]

I don't but it's a good bet that Joe Curto does.

As you most likely know, start out at 12 flats down and work from there.

 

[pbraun]

Yeah - I heard he was so busy he wasn't accepting new orders, so I just ordered from mini mania. Cheaper that Seven Ent by the price of a locking choke cable. 12 flats down . roger. Think I may have just schrunched an EB by grabbing it . oh, well....

 

[pbraun]

but searching a friend found the best buy on an EB needle on eBay at $15.