No. 1. An engine in good condition should have
a gauge reading of 17 to 21 and hand should be steady. Also
study illustrations Nos. 10 and 11. |
No. 2. When opening and closing the throttle
quickly the gauge reading on an engine in good condition
should drop to 2 and com back to 25. |
No. 3. A reading lower than normal and ith the
hand steady indicates that rings are in poor
condition. |
No. 4. Poor adjustment of the carburetor will
cause the needle to float slowly between 12 and 16. See also
illustration 12. |
No. 5. When the hand drops occasionally from 3
to 5 points, from the normal reading, it generally indicates a
sticking valve. |
No. 6. A burned valve will cause the needle to
drop back several divisions each time that particular cylinder
operates. |
No. 7. Leaking valves also show up on the
gauge by the needle dropping back 3 or 4 divisions, whenever
that valve opens. |
No. 8. When needle has a fast vibration
between appoximately 14 and 19 it indicates loose valve
guides. |
No. 9. A steady reading below 5 indicates a
leaky manifold, manifold gasket or carburetor gasket. Also
check heat riser. |
No. 10. When gauge needle is steady at about 8
to 14 it generally indicates incorrect valve timing. See also
illustrations 3, and 11. |
No. 11. A reading of 13 to 16 generally
indicates incorrect ignition timing. See also illustrations 3,
and 10. |
No. 12. When needle drifts slowly between 14
and 16 it generally indicates that plug gaps are too close, or
breaker points are not properly
synchronized. |
No. 13. Wide variations of needle increasing
with motor speed indicates weak, or broken valve
springs. |
No. 14. Normal reading at start, but gradually
drops, indicates choked muffler. |
No. 15. Occasional drop as cylinder is firing
may denote valve open or plug not firing. |
No. 16. If normal is 20 inches and needle
should go to approx 14 check timing. Spark may be
retarded. |
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No. 17. This action usually indicates a leaky
head gasket. |
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