Ski-Doo FORMULA III, Shop Manual

Page: 112 / 356

Section 04 ENGINE
Sub-Section 04 (LEAK TEST AND ENGINE DIMENSION MEASUREMENT)
04-04-1
LEAK TEST AND ENGINE
DIMENSION MEASUREMENT
4
S Series and F Series
LEAK TEST
The following gives verification procedures for liq-
uid cooled engines though it also applies to fan
cooled engines. For FC engines, do not consider
information pertaining to coolant system and crank-
case rotary valve gear reservoir / components.
On twin-cylinder engines, each cylinder can not
be verified individually due to leakage from one
cylinder to the other through rotary valve (except
on engines with separate intake manifolds). Be-
sides, on FC engines, leak will occur through lab-
yrinth sleeve in center of crankshaft.
PREPARATION
1. Remove tuned pipe / muffler and exhaust man-
ifold.
2. Install plug(s) over exhaust flange(s). Tighten
with previously removed screws.
3. On engines with RAVE system, remove RAVE
valves and install plugs over flanges. Tighten
with previously removed screws.
4. Remove carburetor(s).
5. Insert plug(s) in intake rubber boot(s). Tighten
with clamps already there.
6. Using a hose pincher(s) (P / N 529 0099 00),
block impulse hose(s).
NOTE : Do not block large hoses of rotary
valve gear lubrication system.
7. Install air pump on any valve of exhaust plug.
NOTE : If necessary, lubricate air pump pis-
ton with mild soap.
CAUTION : Using hydrocarbon lubricant
(such as engine oil) will damage rubber seal
of pump piston.
8. Rotate crankshaft so that piston goes to BDC
(Bottom Dead Center) on side where the pump
is installed. This will open exhaust port.
9. Activate pump and pressurize engine to 34 kPa
(5 PSIG). Do not exceed this pressure.
10. Engine must stand this pressure during 3 min-
utes.
If pressure drops before 3 minutes, check tester
kit by spraying a soapy solution on pump piston, all
plugs and fittings.
–If tester kit is leaking, bubbles will indicate
where leak comes from.
–If tester kit is not leaking, check engine as
per following procedure.
PROCEDURE
NOTE : A flow chart has been prepared as a
visual reference. See last page of sub-sec-
tion ENGINE 03-01.
Using flow chart and following text, pressurize
area to be tested and spray soapy solution at the
indicated location.
– If there is a leak at the tested location, it is rec-
ommended to continue testing next items be-
fore overhauling engine. There is a possibility of
more than one leak.
– If there is no leak at the tested location, contin-
ue pumping to maintain pressure and continue
with next items until leak is found.
-
TEST PRESSURE : 34 kPa (5 PSIG)
for 3 minutes