1)Tach reading on 3 cyl 2) pulls to RH

[Panel guy]

Hi; I just switched from a '92 40hp Johnson to a '98 70hp Johnson on my 92 Bass Tracker tx 17.

1) The 40 was a 2 cyl, the 70 is a 3 cyl, I am not sure if the tach is reading properly. How can I adjust, or confirm if the gauge is reading right ?

2) Moved up from 27.8 mph top speed to 37.1, but the boat really pull to the rh at cruise speed now.(just got back from lake and I love the new speed!!!!) I read about the tab at the back, but I am confused as to which way to try and turn it ? Should I think of it like a tiller on a sail boat ? and have the front edge of it pointing toward the way the boat pulls ?

3) I had those wing things on my 40 to (I think get up on plane) If I put them on the 70, would that help reduce the porpising at wot and full trim ?

Thanks

 

[tashasdaddy]

Re: 1)Tach reading on 3 cyl 2) pulls to RH

you need to adjust your trim if it's porpising. i get confused on the fin too, i think you move the back the way it's pulling. take a wrench with you and play with it.

 

[Frank Acampora]

Re: 1)Tach reading on 3 cyl 2) pulls to RH

That tab will move the back of the engine in the direction it is pointing. So if your boat pulls to the right, angle the tab so the back end points to the right. The back of the engine (or the prop.) will be forced to the left and the boat will bear to the left. You need to take a wrench with you because adjustment depends on many variables and you need to play with it a little.

 

[Frank Acampora]

Re: 1)Tach reading on 3 cyl 2) pulls to RH

Tachs that are adjustable have a small knob in the back that is turned with a small screwdriver. The knob will have an arrow pointing to a number 1, 2, 3, 4, 6. Be sure the arrow is pointing to 3. If it is pointing to 2, the tach will read high by about 33%.

Non adjustable tachs are signaled off the alternator. If this is how your tach is wired and if the three cyl has the same number of poles as the 2 cyl alternator, then the tach will read correctly.