Engine - Jet Valve Clearance Change

84mitsubishi01

SUBJECT:

JET VALVE CLEARANCE CHANGE
NO. STB-84-09-001

DATE March, 1984

MODEL All with Gas Engine
This bulletin is to inform all technicians of a specification change for 1984 models that also applies to 1983 models:

NOW WAS

Jet Valve Clearance 0.25 mm (.010 in.) 0.15 mm (.006 in.)

The new specification applies to all 1983 and 1984 gas-engine models. The jet valve clearance specification was increased because of the difficulty of obtaining consistently accurate clearances with the former 0.15 mm specification, due to the very light jet valve spring tension.

In addition to the service manual procedures for adjusting jet valves, we recommend a "go-no-go" test as a final proof-check of jet valve clearance.

FIGURE 1:

Use an 0.20 mm (.008) feeler gauge as a "go" gauge, and an 0.30 mm (.012) gauge as a "no go" gauge.

If the jet valve is property adjusted, the 0.20 mm gauge will slip freely between the adjusting screw and valve stem, while the 0.30 mm gauge will have a slight amount of drag. (See Fig. 1)

FIGURE 2:

NOTE: Be sure always to insert the feeler gauge straight in between the jet valve stem and the adjusting screw when adjusting the jet valve. (See Fig. 2)