[C320-list] (no subject)

[Jamie Pett]

List - I had an odd tachometer anomaly this weekend and wondered if
anyone can shed some light ?

 

While motoring home I was monitoring the tach - always try to run at
3100 -3200 rpm which I understand is correct cruising for my motor-
Yanmar engine.  The tach would be reading 3100, and with no noticeable
change in the motor sound / speed etc. would drop to 2800 or so.  Once
or twice it jumped up to like 3400, and I found myself throttling down,
then my speed seemed slow.  ( To make matters worse, my speedo is not
working, and sender is not fouled - guess the sending unit went bad ? So
I am relying on gps for speed which jumps around a bit.)

 

Does the tach. Run off the alternator ?  Could the problem be a belt ? 

 

Any thoughts on why this would happen ? 

 

After running for 20-30 minutes, I go the rpms settled at 3100 and
stayed there steady all the way the home - 2 plus hours into Sunday's
non-existent wind.

 

 

Any insights appreciated - 

 

 

James Pett

'Bella Luna' #614