Tach problem - 90 yamaha

[fisholdschool]

Hi there, I have a problem that you may be able to help me with. I have a 1988 90hp yamaha, and lately the tach has been jumping right up to about 7000rpm when I start the engine... and it stays there..no matter what rpm I am actually at... I checked the connections on the back of the tach and they seem alright... could it be something on the engine side of things??? Thanks in advance for any suggestions.
Tony

[JUSTINTIME]

check them at the voltage regulator also

[remi]

I have a 1989 70hp yamaha with the same problem.When I start it the tach shows 7000rpm all the time eventhough my motor id ideling. Another problem I have now is that it feels like a rev limiter kicks on at full speed and cuts out my engine. My motor must be reading my faulty tack.
I was told its probably the voltage regulator.
Anyone else have this problem?

[Eagle180]

I had the same problem with my tach on my F115 - 4 Stroke Yahama. Thought it was the voltage regulator/rectifier... had the dealer check it out while the boat was in the shop for other items. Everything checked out OK. Dug a little deeper into the problem and decided to replace the tach with a new one... problem solved! My new tach works perfect, so mine was a bad tachometer.

If you do decide to purchase a new tachometer, be sure to google around for best prices.. most sites I found avg. about $70.00 for one, but I did find same brand and model for about $40.00.

Good luck

[remi]

Was your engine also cutting out at high speed?
Do you remember where you purchased the tach for $40.

[Eagle180]

No, my engine was running fine but the tach was all over the place.

http://www.lowcostboatingstore.com/T...-7K_p_435.html

The tach I purchased was the
TELEFLEX 59703P SAHARA TACHOMTER GAUGE
$38.95

It was the exact tachometer that was installed in my boat.

Good luck.