PDA

View Full Version : Tach Adjustment


pram
10-10-2006, 01:28 PM
My tach runs a couple of hundred RPM low. When I was winterizing my boat yesterday :( :( I removed the dash panel to blow out the speedo lines and noticed that there were 2 knobs on the back of the tach, one for the 4/6/8 and the other looked like an adjustment for gain maybe? Unfortunatley it was the one of the last things that I did so all the hoses, plugs battery etc were already out and I couldn't start it to see if it did anything or not. Does anyone know if that is what it is?

Thanks Paul

pram
10-11-2006, 08:01 PM
Sorry about the bump, anyone have any ideas about this?

Farmer Ted
10-11-2006, 08:53 PM
My tach runs a couple of hundred RPM low. When I was winterizing my boat yesterday :( :( I removed the dash panel to blow out the speedo lines and noticed that there were 2 knobs on the back of the tach, one for the 4/6/8 and the other looked like an adjustment for gain maybe? Unfortunatley it was the one of the last things that I did so all the hoses, plugs battery etc were already out and I couldn't start it to see if it did anything or not. Does anyone know if that is what it is?

Thanks Paul


I think the 4/6/8 is for the amount of cylinders your engine has.

jimmer2880
10-16-2006, 07:02 AM
Another bump - because I'm interested as well... my tach appears to be about 250 rpm's off at 3,000.

Yes, the one is for no of cylinders. What about the other?

pram
10-26-2006, 06:02 PM
Just another bump to see if anyone has any knowledge of this.

Thanks

east tx skier
10-26-2006, 06:03 PM
How do you know your tachs are off?

jimmer2880
10-30-2006, 06:53 AM
I know mine is off from when I timed my boat. The Snap-On timing light tach was about 250 rpm's higher than what my Tach was reading.

pram
11-01-2006, 04:49 PM
I'm only making an educated guess about it being low, but it is idling about 450 so I don't think that it is according to me ear..... I also took out my GPS with me the last time I was on the water and at 32MPH I was just under 3000 on the tach. I need to get an portable tach to test it I guess. Would it make sense that there is a gain adjustment on the tach? Are they potentiometers of sorts? I really don't know.

east tx skier
11-01-2006, 04:54 PM
I've gotten 32 mph at a 3,000 rpm baseline in the past (course and gps). Just for grins, you might want to run it wide open and see if your max rpm is what it's supposed to be. Mine will peg right at 4,600, which is what the manual lists as WOT rpm.