Merc tach

[tbjtib]

Hi,I just put a newly rebuilt motor on my boat,but when I ran it(after the recommended break in) and tried full throttle the tach would read up to 8000.The motor Itook off was a 81 90hp inline merc,I put on a 86 115 inline merc.The boat speed was good (45 on a 17'mako) and the motor sounded right,is there a way to test the tach and is it possible for the motor to rev that high and live? Thanks

 

[Hooty]

Re: Merc tach

Sure it'll turn 8. <br />Are you using the same prop you used on the 90hp?<br />If so, it probably did spin up to 8. <br /><br />c/6<br /><br />Hooty

 

[foxjohnc03]

Re: Merc tach

What does the tach read at idle? There may be a switch on the back of the tach that you set for the # of cyls that you have. Was your 90 an inline 6 or 4?

 

[Hooty]

Re: Merc tach

If it's a Teleflex tach, the adjustment on the back is for the number of poles on the alternator. Here's a chart that'll help.<br /><br /> Application Chart <br /><br />c/6<br /><br />Hooty

 

[tbjtib]

Re: Merc tach

It,s the prop that came with the motor,can't read any numbers on ,the tach is a faria set on 6p