Rpm 90 hp vs 50hp

[gwilldo912]

Replaced my 2006 50hp w/ a 1999 90hp and my rpms are off the gauge. With my 50 hp 4900rpm was tops. Now I'm at 7000(maxed gauge out). I have a propco 13/17p and I'm thinking I should be going faster than 32mph w/ the motor trimmed. Do I need to replace my tach or is there some different wiring set up? ANd I guess I need a higher pitch once I figure out how many rpms at WOT.

[99yam40]

the 90 is a 12 pole and the 50 a 6 pole, so need to change setting on tach

[gwilldo912]

thank you

thx and I guess the tach has a switch or do I have to rewire somehow???

[robert graham]

Small slot head screw on back of tachometer with several different positions....

[rodbolt17]

dunno.
who manufactured your tach?

[gwilldo912]

Rpm 90 hp vs 50hp

Came w/ my 2006 Key Largo which had the 50 hp yamaha.

[99yam40]

That still does not say who built the tach or what model it is