tachy tach

[oldboatguy]

Hi Guys,

I have 1984 evinrude 70 hp
last night i installed a tach and a new bilge pump...
the bilge pumps works but i have not tested the tach yet.
it was kind of late at night, neighbors arn't boaters and would not
understand, any way when i turn on the bilge pump... the tach needle
swings up and down for m 0 to 3000 ....when bilge pump is off it
goes to the 0 position....i used a tach wiring harness for the tach
and the bilge pump runs of my fuse block and is grounded to the
neg battery terminal directly....
any thoughts about this
my lead for the fuse block comes of the power tilt and trim wire
because it is off with the key...

 

[ezeke]

Re: tachy tach

Is your tach getting positive and negative feed from the ignition switch? Was the ignition switch off when you tested the pump?

BTW, you should run all accessories off the battery with a separate terminal block.

 

[Silvertip]

Re: tachy tach

Why did you use a tach harness for the bilge pump? I suspect that you have inadvertently tapped the tach signal wire thinking it was a 12V source (which it is not). When you turn the pump on the arcing of the brushes in the motor are sending a signal to the tach. Unless you have an automatic bilge pump, there are only two wires to hook up. Switched +12V and ground. If you have an automatic pump, you have three wires. One hot all the time, one switched +12V and one ground. Check your wiring and stay away from the tach.

 

[oldboatguy]

Re: tachy tach

Thanks
Silvertip :::i just used the wiring harness for the tach....it plugs into control box i wired the bilge pump off the hot wire going to the power tilt and trim
i wanted the fuse block to be hot only when the key is on so as not to run down batteries, i did not want to go directly to key switch in the control box
too complicated....... so the hot wire going from the control box to the tilt/trim motor is hot with key on only. wired a line from it to the fuse block.
the only connection that the tach has to the fuse block is the wire for the light it plugs into the fuse block.. i think it is interfenrence from some where....none of my accesoreis work with out the switch being on...
my bilge pump is not wired for an auto swith because the boat will never be in the water overnight or left for very long with no one in it ....
any more thoughts are welcome

 

[oldboatguy]

Re: tachy tach

Ezeke

yse my tach gets positive and negative feed from the control box by way
of half moon plug....
none of my accessoreis work with out key being on

 

[ezeke]

Re: tachy tach

I was not asking about the ignition switch for that reason. Most of the ignition wiring is not rated for accessories and definitely should not be used for more than gauges and panel lights etc. Accessories should be controlled by a battery switch.

The reason that I asked the question was to find out if you have burned the diodes in your rectifier while setting up, which you may have done.

In standard wiring setup, the only thing that you do want to have on when the boat is turned off is the automatic pump, for the obvious reason that it will keep the boat from sinking.

 

[oldboatguy]

Re: tachy tach

Thanks,
I see what you are saying, even though i tapped a heavy guage wire coming out of the control box it still went through the ignition switch.....
so you recomned a seperate accessory switch for lights bilge pump live well
pump and fish finder ....is that what you ment?

 

[ezeke]

Re: tachy tach

What is confusing is that you say you can turn the accessories off with the ignition switch.

Most have the battery switch on the main positive cable so that when the switch is turned to off, everything is disconnected except the pump, which is wired directly to the battery.


There is plenty of information on boat wiring on-line, and a lot of information is available here: http://forums.iboats.com/forumdisplay.php?f=23