Advertisement
14 Fault diagnosis: fuel system and lubrication
Symptom
Excessive fuel consumption
Idling speed too high
Engine dies after running for a
short while
General lack of performance
Engine does not respond to
throttle
Engine runs hot and is noisy
Chapter 2 Fuel system and lubrication
Cause
Air cleaner choked or restricted
Fuel leaking from carburettor. Float sticking
Badly worn or distorted carburettor
Jet needle setting too high
Main jet too large or loose
Carburettor flooding
Throttle stop screw in too far. Carburettor
top loose
Pilot jet incorrectly adjusted
Throttle cable sticking
Blocked air hole in filler cap
Dirt or water in carburettor
Weak mixture; float needle stuck in seat
Air leak at carburettor joint
Throttle cable sticking
Petrol octane rating too low
Lubrication failure
Remedy
Clean or renew.
Check all unions and gaskets. Float needle
seat needs cleaning.
Replace.
Adjust to figure given in Specifications.
Fit correct jet or tighten if necessary.
Adjust screw. Tighten top.
Refer to relevant paragraph in this Chapter.
Disconnect and lubricate or replace.
Clean.
Remove and clean out.
Remove float chamber or float and clean.
Check joint to eliminate leakage, and fit new
0 ring.
See above.
Use higher grade (star rating) petrol.
Stop engine immediately and investigate
59
Advertisement
Chapters
