Tach not working

[Elmcb92]

I have a 04 tracker pro team 185 with a mercury elpto 90 and cant the tach to work. I've changed the regulator, replaced the connectors, checked all wiring, turned the engine selector switch on the back to clean contacts and still nothing. The tach moves while cranking but falls to 0 after it starts. Even borrowed my buddies tach off his 08 tracker pro 175 with a elpto 50 and his works but it reads 5500 rpms idling. My tach on his boat just does the same thing it does on mine, moves up until it fires off and goes back to 0. Anyone else have a similar problem and figure it out? Thanks

[Transom]

Sounds like your tach is bad. I know that there is usually an adjustment as different brands or even models of engines require different settings. maybe his tach needed to be set differently.

[blkfalc4]

New tach is needed.

[Elmcb92]

Ok so I got the new tach and got it installed and finally got to take the boat out. The tach works idling and with small revs. Give it full throttle and it sticks and wont move until restarted. Any ideas on what to look for??