Walbro carb question

[Larrytkd]

1976 JD 400 Walbro question
I have partially restored JD 400, cleaned fuel tank, new lines, new fuel line filter, new antibackflow fuel pickup in tank, rebuilt at least replaced gaskets, pump diaphram in carb.
It starts, it runs, then dies out after 10 seconds or so.
Here is the first question:

On the JD sleds tech page "Adjusting Carburetor" for Walbro, it indicates the initial settings for the low-speed needle to turn the needle clockwise until seated and then to back it out 1 turn. To adjust the high speed needle it says to turn the needle clockwise until seated and then to turn it clockwise 3/4 turn

In the JD 300/400 operators manual, it states to open the low-speed needle out 1/2 turn and the high-speed needle out 1 1/4 turn.
Which is correct or do you recommend?

When it is running the fuel is circulating back from the carb into the fuel tank so I am pretty sure the pump is working correctly.

Other than that intial setting do you have any other trouble shooting recommendations?
Thanks!

[harleysportster]

Go buy the owners manual and also look on the bottom side of the center engine cover for tuning details. There was a large decal placed there when it was built.
I found this in the service manual.

ADJUSTMENT

Make preliminary carburetor adjustments,
as follows:
High-speed mixture needle: 7/8 turn open.
Idle mixture needle: 1 turn open.
NOTE: On the 800 and JDX8 Snowmobiles (Serial
No. 30001 - ) back the high-speed and idle mixture
needles out 1-1/8 turns for preliminary adjustments.

Start Engine
A CAUTION: Block up snowmobile track
and be certain throttle control is functioning
properly before starting engine.
With the engine warmed up, adjust the idle mixture
needle until the engine reaches highest rpm without
opening the throttle. Then set idle stop screw so engine
idles between 2200 to 2600 rpm.
Take snowmobile for a short trial run or use dynamometer
and make final adjustments. Adjust highspeed
mixture needle until full engine performance is
obtained, then open high-speed mixture needle an
additional 1/8 turn.
IMPORTANT: Too lean an adjustment will
cause engine damage, such as piston burnthrough
and scored piston and cylinder walls.
Under no circumstances should the carburetor
setting on the reed valve engines be set less
than 7/8 turn open.
Install console and windshield after adjusting carburetor.
Carburetor mixture needles can be adjusted
with console installed

[Larrytkd]

Thank you! I will give it a try.
Larry