Yamaha PZ50W 2007 Service manual

SNOWMOBILE 12/18/07 S2007-011
2007 PZ50W/FXW/GTW/MW/VTW
Hard Starting in Extreme Cold Temperatures
PAGE 1 of 4
©2007 YAMAHA MOTOR CORPORATION, U.S.A.
Symptom: Some affected units have experi-
enced hard starting in temperatures
below -15ºF (-26ºC).
Cause: Reduced engine cranking speed in
extremely cold temperatures affects
the engine decompression and
ECU calibration. This can reduce
the engine starting performance.
Remedy: Install ECU kit, which includes
a new ECU, two decompression
springs, and a cylinder head cover
gasket (see Parts Information sec-
tion for more details).
Additional
Notes: It is normal for the engine to crank for several seconds before starting. However, early-season
extended-cranking time or engine not starting in temperatures above -15˚F (-26˚C) is usually
associated with the following:
• Stale gasoline (more than 30 days old) or summer-blend gasoline;
• Contaminated spark plugs caused by stale gasoline; or
• A weak or discharged battery caused by long cranking.
• It can also be caused by repeatedly starting and stopping the engine without allowing the
engine to reach operating temperature.
Should this be the problem, then perform the following:
1. Drain the fuel from the machine and replace it with fresh premium gasoline.
2. Replace the spark plugs.
3. Charge the battery properly using the correct charger.
4. Do not start and stop the engine without allowing it to reach operating temperature.
Sold
Units: Contact those customers who have reported hard starting in extreme cold temperatures and
arrange a convenient time to install the new exhaust decompression springs and ECU.
Unsold
Units: N/A
Parts
Required: Yes, Order one ECU kit per unit as required.
Warranty: Submit a Service-Per-Bulletin (90 Code) Warranty Request for parts and labor. This 90-code
expires December 31, 2009.

PAGE 2 of 4
For the following procedure, refer to the appropriate
sectionsintheServiceManual(P/N:LIT-12618-02-58)
available on YDS.
1. Remove the seat, fuel tank and any other parts
(side panels, tank cover, and spark plug caps) to
access the engine cylinder head cover.
2. Disconnect the negative (-) cable from the bat-
tery.
3. Remove the cylinder head cover.
4. Position the camshaft, by using the primary
clutch to turn the engine in the normal direction
of rotation (clockwise), to access the exhaust de-
compression spring.
Always turn the crankshaft in the direction of
normal rotation (clockwise).
5. Place a rag in and around the cam chain pas-
sage to prevent items from falling into the bot-
tom of the engine.
NOTE: Removing the camshaft is not required. A
removed camshaft is illustrated as an example.
6. Remove the decompression spring as shown
in the adjacent photo. Take care not to drop the
spring into the engine.
All 2007 PZ50W (Phazer)
All 2007 PZ50GTW (Phazer GT)
All 2007 PZ50FXW (Phazer FX)
All 2007 PZ50MW (Phazer Mountain Lite)
All 2007 PZ50VTW (Venture Lite)
CAUTION:

7. Install the new decompression spring.
NOTE: Check that the spring is properly installed
as shown in the adjacent photo.
8. Using the primary clutch, turn the engine in the
normal (clockwise) direction of rotation to access
the other spring. Install the second spring.
9. Check the decompression operation. By moving
the weights outward by hand, when working cor-
rectly, the weights will return to their initial posi-
tion.
10. Re-install the cylinder head cover using the new
gasket supplied in the kit.
Apply Yamabond 4 Motorsports to the cover 1
surface and the mating surfaces of the cylinder
head cover gasket and cylinder head 2.
Tighten the cylinder head cover bolts in gradual
steps and in a crisscross pattern.
PAGE 3 of 4
Yamabond 4 Motorsports:
ACC-BOND4-MC-00
Cylinder head cover bolt tightening
torque:
12 Nm (1.2 m•kg, 8.7 ft•lb)

11. Exchange the ECU with the new one in the kit.
12. Reconnect the negative cable to the battery.
13. Reinstall the fuel tank, seat, and the other parts
removed in step 1.
14. Tag and hold all replaced parts (ECU and
springs) for 120 days from the date of request.
If you encounter an unfamiliar unit and you are un-
sure if the unit has been modified, check the ECU
(see adjacent illustration).
Alternatively, you can check the modification status
by checking Unit Status under Service/Warranty
Claims on YDS or by contacting your Regional Tech-
nical Advisor (RTA).
Part Number Description Qty.
90891-50145-00 PZ50 Mountain Lite ECU Kit (Fits PZ50M only) 1
90891-50146-00 PZ50 ECU Kit (Fits all other PZ models) 1
PAGE 4 of 4
ID MARK:
FOR MOUNTAIN
LITE MODELS
(90891-50145-00):
ORIGINAL: 8GP-00
NEW: 8GP-10
FOR OTHER MODELS
(90891-50146-00):
ORIGINAL: 8GC-00
NEW: 8GC-10
Service of all affected units is authorized regardless of warranty status until this 90-code expires on December
31, 2009.
To receive credit for the parts and labor, select 090UG from the Problem Code pull-down menu in the Yamaha
Dealer System (YDS). If submitting a paper warranty claim, use Problem Code 90UG The labor allowance
for this modification is 1.1 hours. Tag and hold all replaced parts (ECU and springs) for 90 days from the date
you submit your claim.
NOTE: This kit includes: One ECU, two decompression springs, and a cylinder head cover gasket.You will also
need a small amount of Yamabond 4 Motorsports (ACC-BOND4-MC-00).