My Yamaha 150V tachs.
 

I am installing a 1997 Yamaha 150V onto my 1983 V20. The old Wellcraft cluster panel is still remaining on my boat. Does anyone know if those old tach, fuel, trim meter will work with my motor? Or can I use any newer meters with my motor? Or do they need to be Yamaha?

Not sure but I would hook them up and see. Unless you want to buy new stuff. Fuel should work because that doesnt have anything to do with motor.

I’d think volt meter should be fine too. Volts are volts, wherever they come from, unless there’s some computer in the mix.

Makes sense. I wont be buying anything yet until I test the old meters.

Installing my Yamaha 150 outboard
 

Another question I have is should I also install a Transom Mounting Bracket Plate before I put the motor on for stability? Its seems to me that it would add extra strength to the transom. Would there be any drawbacks to doing this?
I was also thinking of adding some Transom Support Plates on the inside of the boat. With both the bracket and the support plate, I would be adding another
5/8" to the length of the transom bolts. Would this make a difference? Has anybody done this?

If you go with the old school style gauges, you wont have any issues( dial or digital) what you don't want is any of the newer style CAN BUSS linked gauges( Command Link?). Anything with more than basic data is going to be CAN BUSS and wont work with your motor. . Most aftermarket gauges are old school and will work. As far as your mounting choices, I'm not sure what you are talking about. If you're speaking of a plate that goes on teh outside of teh boat, they are usually used if theres a transom issue. The inside the boat plate that goes between the top two bolts is fairly common and cant hurt. I had one for teh top two bolts and made one for the bottom two bolts.