Merc 470,tacho not working after alt conversion.

[Grums ssv-177]

Hi all, i did an alternator conversion 6mths ago after i had excessive voltage running through the boat, and it's going great ever since ( thanks again to those who helped out!), but my tacho has not ben working since. I tried to test it by running a jumper lead but no success. I was looking at buying a new one but figured it may be something to do with the fact that it probably ran off the stator/rectifier and now that has been made obsolete so i'm wondering if i have disconected to many wires whilst doing the conversion or if it needs to be re-routed seeing as i am now running an alternator?

Any help would be appreciated as i would like to keep the boat in origional condition, but i can land a set of gauges new gauges cheaper than i can replace the one!

Cheers Graham

 

[Bondo]

Re: Merc 470,tacho not working after alt conversion.

Ayuh,.... Tachometers get their signal from the Coil....

 

[Grums ssv-177]

Re: Merc 470,tacho not working after alt conversion.

Yeah i knew they run from the coil, and it is connected via the negative side of the coil, But i had read somewhere about a connection to the rectifier, so i was double checking that avenue to rule it out, also being that i had removed all wiring to the stator and rectifier i wasn't sure if i had removed a link somewhere which could effect it. I am going to re-check all connections through the line, and also run a jump lead to the coil and also jump lead the positive ciruit to the tacho and if it still doesn't work assume that the tach is stuffed and order a new one.

cheers

 

[achris]

Re: Merc 470,tacho not working after alt conversion.

Yeah i knew they run from the coil, and it is connected via the negative side of the coil, But i had read somewhere about a connection to the rectifier, so i was double checking that avenue to rule it out, also being that i had removed all wiring to the stator and rectifier i wasn't sure if i had removed a link somewhere which could effect it. I am going to re-check all connections through the line, and also run a jump lead to the coil and also jump lead the positive ciruit to the tacho and if it still doesn't work assume that the tach is stuffed and order a new one.

cheers

Outboards....

If the positive and negative on the tacho are good and the wire from the coil to the signal on the tacho is also good, then the tacho is crook, and needs to be replaced. Get a cheap tacho just to test, and go from there.