Yamaha Waverunner VXS VX1800 Service Manual page 308

Symptom 2
Fuel not supplied (all
cylinders)
Compression pres-
sure is low
Symptom 1: Unstable engine idle speed, poor acceleration, poor performance, or limited engine
speed
Symptom 2
Throttle valve does
not move properly
Cause
Fuel leakage
Blown fuse
Clogged fuel pump filter
Fuel pump module mal-
function
Fuel pump relay malfunc-
tion
Compression leakage
Improper valve timing
Cause
Throttle valve malfunction
Checking step
Check the fuel hose.
Check the fuse for continuity.
Clean the fuel pump filter.
Check the fuel pump module opera-
tion sound using the YDIS.
Measure the fuel pump module in-
put voltage.
Check the blue (L) and black (B) fuel
pump module leads for continuity.
Measure the fuel pressure.
Check the fuel pump relay.
Measure the compression pressure.
Measure the valve clearance.
Check the camshaft for damage.
Check the cylinder head gasket and
cylinder head warpage.
Check the valve and valve seat for
wear.
Check the piston and piston ring for
damage.
Check the cylinder for damage.
Check the timing chain.
Checking step
Check the ETV.
9-17
Engine unit troubleshooting
See
page
4-1
7-3
7-31
4-12
4-12
4-12
A-2
4-3
7-29
5-1
3-11
5-35
5-47
5-48
5-76
5-76
5-76
5-37
See
page
4-7