Tach sits at 600rpm with the key off - Branson

Outlawmoon · Aug 12, 2020

Back to the forum I come.....

This is a new one for me...right now the tach on my Branson 4720h is sitting at 600rpm with the key off.... Of course as soon as I start it it goes to about 1200 rpm. If you subtract the 'at rest 600rpm' then the reading is about right at about 600rpm...

Has anyone had this happen on their Branson? Mine is a 2016 model with ~500 hours on it.

Thanks!!!

RSR · Aug 12, 2020

Outlawmoon said:
Back to the forum I come.....

This is a new one for me...right now the tach on my Branson 4720h is sitting at 600rpm with the key off.... Of course as soon as I start it it goes to about 1200 rpm. If you subtract the 'at rest 600rpm' then the reading is about right at about 600rpm...

Has anyone had this happen on their Branson? Mine is a 2016 model with ~500 hours on it.

Thanks!!!

I'm going to take a totally wild stab at this. I'm assuming it's a physical gauge that shows RPM? It may be connected to the shaft of the engine like on older cars. Simply a cable that can spin within a housing.

I had a speedometer cable give out on an old car years ago. The speedometer gave all sorts of wonky readings before it finally just stopped working. It was a quick and cheap fix to replace the cable.

ptsg · Aug 12, 2020

The tachometer gets signal from a Brown wire on the alternator. Not sure if it helps, but you can always wiggle the wire.

The idling speed should be around 1000 rpm.

Outlawmoon · Aug 12, 2020

Well the fire is out..... Thanks ptsg. I pulled the dash, popped out the two connectors, used some canned air (the wife was busy) got the dust out. Started it up, the tach went to zero and then to 1000rpm - just like it is supposed to. I had thought it was roughly 600rpm for idle but ptsg set me straight.

Must have been some dust or something in there because for the last couple of hours it's been just perfect! My 'old engineering professor would have said it was FM. Friggin Magic............