NO RPM reading on 2003 Yahama multitach

[ReelMojo]

I have a 90HP 2003 Yahama. The RPM's were registering perfect. I had the boat in the shop and the water pressure gauge was replaced. Now the RPM's are not registering. The rest of the guage is working fine. Any hints?

I'm trying to solve this myself at the moment.

Thanks

[99yam40]

I would call the shop and ask them what they might have done to cause it. They may have disconnected something