Polaris Mikuni Tm38 Carburetor Air Screw

Pilot Screw Help!
I have a 2004 Magnum 330 4x4. I've owned it for three years and bought it from a polaris dealer mechanic in southern IL. It has run flawlessly, and in the brush/woods keeps up with my brother's 500 Sportsman. We are both impressed with this bike. However I only use it regularly for 3 months of the year (deer season, duh!). I have kept it on a trickle charge the rest of the year and regularly start it/run it/drive it, every two weeks or so.
Let me color inside the lines. I have done nothing to this bike, as far as mods go (new tires, but that doesn't count). Strictly stock with no adjustments. I used Sta-bil fuel stabilizer in it after deer season (the same time that I winterize my lawn mower). I also put Heet in the tank in the spring to get rid of any water in the fuel. And I use a carb cleaner in the fuel to help clean the carb during the run on it's first tank.
Fast forward to this year. It had been running fine this summer, but started giving me some starting/idling issues this fall (pre-deer season). Had hard starting/idling/stumbling problems. Keep the choke out and I was able to get it started and keep it running. Once warmed up, I was able to close the choke and ride it normally. I just figured that it was a fuel issue and put in fuel dryer and carb cleaner. But during deer season it got worse and then died right as I got back to camp. I couldn't get it started and had to push my bike onto my trailer to get it home.
I researched this problem and found that other bikes have had this same problem. Basically, a varnished carb/jets. So I got a rebuild kit from my polaris dealer. Watched a few videos to refresh my memory on working with carbs (WOW, a lot different from Holley carbs). So I tore into it and marked my parts, kept them in order. Oh yeah the needle jet? was originally clipped at 3 of 5, so I clipped my replacement needle/jet at the same. Middle of the road, not too lean, not too rich. When I started to put it back together, I found an extra screw/jet that didn't come in the kit.
OOPS!, I had removed the Pilot Air/Fuel screw and didn't count my turns. Apparently, this carb had been removed/rebuilt before because I didn't remove any plugs to get access to it.
Does anyone know where to set my screw as a starting point? I'm thinking two turns out and adjust it from there..any thoughts? Any other carb adjustments to think about?

Any other ideas on my full-out tune-up? New sparkplug, inline fuel filters, and fuel line are already done.
Thanks to everyone in advance.
Wayne
St Louis, MO

Mikuni

MIKUNI TM SERIES FLATSLIDE CARBURETORS


TM Flat Slide Standard Jetting Specifications
CarbMain jetMain air jetPilot jetPilot air jetNeedle jet Jet needleThrottle valveFloat heightMikuni partPart number
TM244/042 #130FixedVM22/210 #15454 Series #Q-05N13832-30006 #3.023mmTM24-8001001-017
TM284/042 #1801.8VM22/210 #15175 Series #P-85DP39832-33001 #2.523mmVM28-418001-023
TM324/042 #250NoneVM22/210 #45389 Series #Q-25FP17832-39012 #4.018mmTM32-1001-026
TM344/042 #280NoneVM22/210 #50389 Series #Q-25FP17832-39012 #4.018mmTM34-2001-033
TM364/042 #280NoneVM22/210 #50389 Series #Q-26FJ40832-43002A #4.018mmTM36-2001-038
TM38 (*47mm)4/042 #230NoneVM22/210 #22.5389 Series #Q-26FJ41832-43011 #4.018mmTM38-85001-060
TM38 (*43mm)4/042 #230VM22/210 #22.5389 Series #Q-26FJ41832-43011 #4.018mmTM38-86001-061
TM39 PRO series4/042 #230VM22/210 #22.5389 Series #Q-26FJ41832-43011 #4.018mm001-194
TM41 PRO series4/042 #230VM22/210 #22.5389 Series #Q-26FJ41832-43011 #4.018mm001-196
TM Flat Slide with Accelerator Pump Standard Jetting Specifications
CarbMain jetMain air jetPilot jetPilot air jetNeedle jet Jet needleThrottle valveFloat heightMikuni partPart number
TM33N100.64 #127.50.7VM28/486 #37.51.1640 Series #P-85FP96832-38007 #1.514mmTM33-8012001-032
TM36N100.64 #130NoneVM28/486 #12.51.0568 Series #P-89DZH6-50TM36/137 #2.019mmTM36-68001-552
TM40 (HS40)N100.64 #165PluggedVM28/486 #17.51.1568 Series #Y-69DJY04-96TM40/8119mmTM40-6001-085
*47mm = Spigot O.D. size, *43mm = Spigot O.D size.
For exploded view carb parts

TM POWER JET KIT

TM POWERJET KIT 002-041
The Power Jet Kit is used on 2-stroke engine applications to improve mid-range throttle response and add additional fuel to wide open throttle running conditions. Easily installs on TM series Carburetors (#80, #100 and #120 sized jets included). Sold as a kit.

TM Cable Type Starter System Kit. Replaces knob plunger type starter system with a cable type starter
system. Sold as a kit. Two Kits available:

Order No. Crack core impact 7.5. 002-351
Fits the following TM Carburetors: TM32, TM34, TM36, TM38
and 39mm Pro-Series, 41mm Pro-Series
Includes items A - F.

Order No. 002-353
Fits the following TM carburetor: VM28/418 (TM28)
Includes items A - F.

A. Starter Plunger Top, Rubber Cap VM26/46 002-061
B. Cable Adjuster M21/14 002-062
C. Cable Adjuster Locknut B30/247 002-065
D. Starter Plunger Fitting VM15/37 002-093
E. Starter Plunger Spring VM32/69 002-094
F. Starter Plunger (TM32-TM41) VM15SC4/85 002-095
Starter Plunger (TM28) VM15SC4/86 007-751

Pilot jet VM22-210
Main Jet 4/042

TM Series Throttle valves

TM24 (TM24-8001) 3.0 832-30005 002-951
TM28 (VM28-418) 2.5 832-33001 002-804
TM32 (TM32-1) 4.0 832-39012 002-800
TM34 (TM34-2) 4.0 832-39012 002-800

Old Style TM 36, TM38 Carburetor with Top Idle Adjuster Rod
TM36 (TM 36-2), TM38 (TM38-1, TM38 (TM38-3)
2.5 832-43002 002-734 No longer available
3.0 832-43002 002-735 No longer available
4.0 832-43002 002-737
5.0 832-43002 002-739 No longer available

New Style TM 38 Carburetor, with Side Idle Adjuster Screw
TM38 (TM38-85), TM38 (TM38-86)
2.5 832-43011 007-401
3.0 832-43011 007-402
3.5 832-43011 007-403
4.0 832-43011 007-404
4.5 832-43011 007-405

TM33 Pumper (TM33-8012) 1.5 832-38007 002-948
TM40 (HS40) Pumper (TM40-6) TM40/81 007-430


TM40 (HS40) Rubber Flange Adapters HS40-6K I-VM36-200-1 002-054
TM40 (HS40) Rubber Flange Adapters HS40-7K I-VM38-200-1 002-055
TM40 (HS40) Rubber Flange Adapters HS40 All KHS-004 002-986

HS40 Carb Adapter EVO Adapter Ring MK-413 005-095

TM40 (HS40) Throttle Cables Throttle Cable (Pull) RS36/34-A 007-210
TM40 (HS40) Throttle Cables Idle Cable (Push) RS36/35-A 007-211


Jet Needle TM36 #9DZH06-50 (Std) 007-109
Jet Needle TM36 #9EBY01-51 2.51 Leaner 007-106
Jet Needle TM36 #9EBY01-50 2.50 Richer 007-105


Jet Needles TM40 (HS40) #9DJY01 2.97 007-015
Jet Needles TM40 (HS40) #9DJY03 2.96 007-017
Jet Needles TM40 (HS40) #9DJY04 2.98 007-018
Jet Needles TM40 (HS40) #9DJY02 2.95 007-016

007-731This adjuster has threads on one end, the other end swivels. Includes rubber cap, locknut, cable adjuster and 90º tube. Works on Keihin and Mikuni carburetor caps.

The kit 007-731 contains:
002-061 rubber cap
002-065 nut
007-757 adjuster
007-759 90 degree threaded tube

FOR EXPLODED VIEW PARTS

Jan 29, 2018  A clean Mikuni carburetor with a properly adjusted float valve will perform very well. Main and Primary Jets may be changed out to suit conditions or loads, but these are the basic adjustments.