Tach hookup ?

[catman48]

Can I attach the tach to my 04 9.9 4-stroke bigfoot? There are 3 wires from tach ,1 brown, 1 black ,and one purple, I have a OEM mercury service manual but don't see anything in there for it.

 

[ricksrster]

Re: Tach hookup ?

Is it electric start and charge the battery?

 

[catman48]

Re: Tach hookup ?

Yes

 

[ricksrster]

Re: Tach hookup ?

The brown wire hooks up to either stator wire on the rectifier. The purple is 12+ DC from the ignition switch, key on position. The black is ground. Does it have a light? If it does, that hooks up to your nav. lights. I believe the take setting should be 4P. Check here: www.teleflexmarine.com/cgi-bin/frameset2.cgi?site=gauges&type=us&link2=1047

 

[Don S]

Re: Tach hookup ?

I'm not sure you can use a regular outboard tach with that engine. Look at page 9A-8 of your manual. It shows which wires to hook the tach to, but the connections are coming out of the electronic control unit white wire to the tach and the yellow wire from the tach to ground.
It's a tach for reading digital signals from ECU, not pulses from a stator (which this engine doesn't have),

 

[catman48]

Re: Tach hookup ?

Ok I got a tach hooked up and went to the lake, and got up to full throttle, It's showing between 2300-and 2400 RPM's. Is this about right or do I have a prop mismatch or some other problem ?

 

[Don S]

Re: Tach hookup ?

2300-2400 isn't even close, only about half the rpm needed. Need a SN to tell you the exact range of WOT rpm, but for sure it should be in the 5000 rpm range.
That big a difference is not something a prop change will cure.
Did you read my previous reply to your question?

 

[catman48]

Re: Tach hookup ?

Yes I read previous reply, I see in my manual, range should be 4500-5500. Are you saying the tach reading is inaccurate ? My tach is working from the outboard connector.I bought this motor new it has less than 6 hours on it, What could be causing low rpm's

 

[Don S]

Re: Tach hookup ?

Just because your tach is hooked to the ouboard connector, doesn't mean it's the proper tach, or adjusted properly.
No one knows what kind of tach you have, or even if it is compatable with your motor. If it isn't compatable, the possibilities are that it is either inaccurate, or doesn't work at all.
Is this a Merc tach for your engine model, or some aftermarket tach you hope works? What is it's make, model and part number.

 

[yamamarinetech40]

Re: Tach hookup ?

Sounds like it's reading half of real RPM's....you need to check the settings on the tach....

 

[catman48]

Re: Tach hookup ?

It is an original mercury tach on my bass tracker, I also have the original 35 horse outboard that was on the boat. Most places I fish only have a 10 horse limit, And there are only a couple within 75 miles I can use the bigger motor.

 

[ricksrster]

Re: Tach hookup ?

I believe the take setting should be 4P. Check here: www.teleflexmarine.com/cgi-bin/frameset2.cgi?site=gauges&type=us&link2=1047