My Beta 20 consistently indicates low. Only about 100 rpm at idle and about 500 at WOT. This was verified with a optical rpm gauge. The cylinder select switches on the back of the gauge make no difference (pretty sure they shouldn't anyway). All connections look good at the gauge and the alternator.
Any ideas?
Thanks,
Carl
-- Edited by Opie91 on Monday 13th of January 2014 07:41:31 PM
From your description, you have an old engine with a Datcon tach. We have not used these for about 12 years.
The tach gets its signal from the alternator. Verify that the AC terminal is producing about 6 to 9 V AC and that all terminals at the back of the tach, in the multi pin plug at the engine and the lead coming out of the alternator are clean with no corrosion.
There is a calibration screw inset at the back of this tach. You need a small allen wrench to adjust it. The cyl select should make some differance which leads me to think that it may be time for a new tach.
