Ski-Doo Formula S 1998, Shop Manual

Page: 98 / 338

Section 04 ENGINE
Subsection 04 (LEAK TEST AND ENGINE DIMENSION MEASUREMENT)
04-04-1
LEAK TEST AND ENGINE DIMENSION
MEASUREMENT
0
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
crankcase 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 mani-
fold.
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 piston
with mild soap.
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 PSI). 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 this chapter.
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.
-
CAUTION
Using hydrocarbon lubricant (such as en-
gine oil) will damage rubber seal of pump
piston.
TEST PRESSURE: 34 kPa (5 PSI)
for 3 minutes