I have a 1982 Black Max 150, just looking for a correct tachometer to replace my existing. The existing one doesn't sweep very well and hangs up at 3500 rpms. It is the original 1982 tach. The fuel gauge also jumps around quite a bit and never sends a true signal. Could be the sending unit but since all of the gauges are old figure it could use one. Boat is a 1982 Procraft 1650 Pro. Thanks in advance.