Tach Problem

[rob 135]

I have 1973 Johnson 135, on a 1979 silverline tri hull. my problem is tach doesn't read right and won't go over 3 grand. This is second tach and same results. Both set for 12 pole . Checked AC voltage on gray wire , has around 10 volts . Engine runs 33 mph on gps . Battery charges fine 13 volts at idle and goes up from there. I would think at 33 mph would be over 3 grand . Any help please .

 

[rob 135]

Another thing ,when I replaced stator there was a option of , 6 amp or 12 amp . I have the 6 amp one. Was thinking that might be problem ,but how do I make tach read correctly?

 

[SparkieBoat]

maybe your rectifier is not working properly. free troubleshooting guide in the link in my sig. that is a nice motor by the way, those 73 135s are supposed to be some bad boys. make sure you run 93 octane in that motor for best results.

 

[rob 135]

I have checked regulator ,test fine and charges battery. Great engine I put all new pistons in last year . Had 3 melted up pistons . I always run 93 octane . motor has some big compression . Just need to get tach fixed

 

[V153]

Don't think the stator amperage has anything to do with it. Still same # of pulses.

Mebbe you got a cruddy wire running to it? Check the resistance of the leads?

 

[gm280]

I would check the rectifier to make sure all sections of it are working. If one diode is shorted, it could make your tach read odd because it would negate some of the pulses... But that is just my thinking...

 

[SparkieBoat]

the steps to test the rectifier are at this link, click on the installation sheet PDF.
http://www.cdielectronics.com/produc...17200-9-17200/

You can upgrade to this part number and it has a voltage regulator as well to prevent over charging of your battery. [h=1]CDI 193-3408[/h] .. I will bet you a gallon of premium synthetic 2 cycle oil it is the rectifier or wiring harness short. :watermelon:
Also if you melted 3 pistons, I would consider retarding the timing a couple of degrees or possibly going 1 or 2 sizes up on my main jets.. But that is just me.