tachometer trouble

[suzukidave]

I have tachometer confusion. Are all tachs not the same? Is there a way to calibrate a tach?<br /><br />My tach died last year and I replaced it this year with the exact same model (teleflex amiga universal). The new tach says my 55 suzuki is doing about 400-500 rpm more than the old one did at the same speedo reading. The boat will rev w-o-t to 5900 rpm, when it used to top out at 5400. W-O-T for the motor is supposed to be 5500 rpm. I bought a tach in the first place because I was convinced I was underpropped (I've got an 11x11inch prop on a 16 foot deep v and it just jumps onto plane). Now I'm wondering if I was right the first time.<br />Any suggestion on how can I sort out which tach to trust?<br />thanks<br />suzukijoe

 

[corm]

Re: tachometer trouble

Hi suzukjoe,<br />Does the tach have a switch for different pole alternators? If so is it set to the correct setting. Is it set the same as your <br />old one? Can you try it on a friends boat to match it against his tach. Or most dealers<br />have a tester to simulate motor operation.<br />They could test it for you. Most tachs are only accurate to 200 RPMs anyway,but you do need a base line on it for proper prop choice.<br />...have fun...corm

 

[suzukidave]

Re: tachometer trouble

thanks corm,<br /><br />the pole setting is the same as on the old tach. No easy solution. Finding a Second tach was a good idea but where to find one compatible and then which one would be right? Dealer wants to pull the motor to cross-reference the tach to his tester in his tank. I need to do soemthing about my steering cable anyway (really really stiff) which requires pulling motor so I'll try to kill two birds with one service.<br /><br />thanks again<br />suzuki joe