Tachometer help

mltessier

Seaman
Joined
Mar 31, 2018
Messages
50
Hi,
Recently bought a boat (Four Winns H170-Volvo Penta 3.0) and have been doing maintenance on it. When I start the boat up, the tach shows that the engine is idling high 1200RPM's. It seems to me that the engine is not running that high. I then noticed that when I first turn the key (first position) the tach goes up to 300rpm's before the engin is started. Is this normal? Could it explain why I'm getting high RPM's when I'm actually not.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,306
first, you need to verify the tach with a known good shop tach.

my engine idles at 1500 RPM when I first start it until I pull it back, not sure why you think 1200 is not in the realm of reality

verify your tach first.

the 300 RPM showing could be your dash tach going out. they are for all intensive means, a $.070 digital to analog converter with a $1 air core wrapped in $2 worth of glass, plastic, and a decal. they are not the most sophisticated devices.
 
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