OS91SZ OMIcarb./Cline/Viper - needles and Shims...

[Knud Pedersen DENMARK]

Hi,

Just installed a Os91SZ with OMI BB Carburator, Cline regulator and Viperhead (with OS8 and Enya 3 - or 4)
it is sitting in my old Fury Extreme, with a Hatori 939 (almost an Sb18), revlock 10, running on 30% LV Wildcat.
Running 15750-16000 omdr.

My problem is that when hovering or fliging circles in Idleup1 or 2, the engine misses some turns approx. evry 15 sec. (the engine is not running smooth)
If switching of the Revlock, the probleme is almost gone.....

- should I use some Headshims?
EDIT: just read the Viperhaed manual :) :"2 .008shims for 30% nitro" - I will installed them tommorow (bought the engine with cline ad viperhead from Skyline , Bob J, don´t know if he has placed some shims under the head,,,,,but i will soon know:-)
:mrgreen:

- What needles setting are you guys running?
- did a search, and could see some are running the engine with the med-needle fully cloesed....?
- what RPM are you ruinng?

ChopperKnud

[Timbers]

I'm running the same setup, running Magnum 30%. Main needle is about 1.25 turns out, midrange needle is about 5 clicks from open.

I am running .024" of shims under my stock head. Haven't really been able to make my engine run smooth since I had it modified.

[Jafa]

Knud, you need to tune it for your conditions,
your level above the sea and humidity is likely to be different

Certainly the SZ's have a bigger opening on the ducifier (spelling?)
and seem to provide too much fuel
hence numerous people running with the mid needle near closed

[Knud Pedersen DENMARK]

Hi,

I installed an .008 shims (plus the one that Bob J already has installed), and moved the OS8 glow to the angled position, and installed an Enya5 in the straight hole....
Turned the midrange to 1/5 open...

That really help, now the popping sound every 10 sec is gone, and the engine is running much smoother

:mrgreen: :D

ChopperKnud