i had the boat out yesterday, and at one point, i noticed that the port tac on the upper station was jumping a bit. it took several minutes for it to stop, and then it only did so after i increased the rpms a few hundred revs.
this is a new tac ( i just had all the upper guages replaced this winter/spring).
while this was happening, i didn't notice a miss or anything wrong with the 'feel' of the port engine.
thoughts?
Jumpy Tachometer
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Jumpy Tachometer
Terran
1986 Silverton 40' Aftcabin
Terran
(former 1977 F-32)
1986 Silverton 40' Aftcabin
Terran
(former 1977 F-32)
Possibly EMI noise getting introduced on the sending wire from the coil. Also possibly a bad connection. Was it jumping to higher RPM or lower RPM? The first would tend to indicate EMI while if it is the second I would lean towards bad connection. EMI would be introduced by other wires (with higher voltages) running close to the tach sending wire.
But you can't rule out bad tach even though it is new. A lot of tachs are easily damaged by strange things. I have a tach (on my little boat - came with the boat) where the user manual said to not jump start the engine from another engine because it could cause damage. Sounds like a bad design to me, but what do I know.
But you can't rule out bad tach even though it is new. A lot of tachs are easily damaged by strange things. I have a tach (on my little boat - came with the boat) where the user manual said to not jump start the engine from another engine because it could cause damage. Sounds like a bad design to me, but what do I know.
- alexander38
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loose ground will cause it to.
Carver 3607 ACMY 454's Merc's
10' Dinghy 6hp Merc.
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10' Dinghy 6hp Merc.
La Dolce Vita
Let's hit the water !
http://s852.beta.photobucket.com/user/t ... 8/library/