SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: Kyle700 on November 14, 2013, 01:43:19 PM

Title: Tach inop
Post by: Kyle700 on November 14, 2013, 01:43:19 PM: The needle is stuck at about 1100 rpm's both hooked up and out of the boat. I have 12 volts coming to the tach at the "Send" post. What else do I look for. I checked all the connections.....
Title: Re: Tach inop
Post by: Kyle700 on November 20, 2013, 02:15:40 PM: The wire that comes from the distributor labeled "tach", does it go straight the tach post labeled "Send". It is currently attached to a terminal strip (hot)..?

Thanks
Title: Re: Tach inop
Post by: ka0tyk on November 20, 2013, 02:53:20 PM: the tach should have a red 12v from ignition switch to the 12v, a black ground to the ground, white to lights, and the signal wire should come from the distributor (HEI), coil, or from the msd box if you have one. plugging a 12v directly into your signal wire COULD have damaged it...

(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.fordmuscleforums.com%2FTEX%2FProformDist%2Fproformdist_2.jpg&hash=618fd9c2ac7275a7d8a796a09cebcb777fecfbc6)

the HEI distributor should have a 12v lead from ignition switch (use a fuse!) and then the "tach" or "signal" wire goes directly to your tach.

lastly tach's are universal and most have a switch or a wire that is usually cut to switch it between 4/6/8 cylinders in case its not reading properly.
Title: Re: Tach inop
Post by: Kyle700 on November 20, 2013, 03:16:00 PM: It was never wired direct..
However, I might be a lil stupid because I'm not following ... "HEI distributor should have a 12v lead directly from the battery (use a fuse!) and then the "tach" or "signal" wire goes directly to your tach."
My dist looks like the one in your pic. Where does the wire go to, from the distributor "tach" post?

As mine sits, the wire goes from the "tach" post on the dist, to a terminal block, then a different wire goes from the terminal block to the tach "Send" post...
BTW this boat was rewired at some point, because very few of the wire colors are what they should be according to wiring legends I've looked at...

Thanks for you help!
Title: Re: Tach inop
Post by: ka0tyk on November 20, 2013, 03:40:47 PM: does this help?

(https://scontent-b.xx.fbcdn.net/hphotos-prn1/560125_10151840995524833_108325266_n.jpg)
Title: Re: Tach inop
Post by: Kyle700 on November 20, 2013, 03:47:17 PM: Yes, absolutely perfect!

Thank you!
Title: Re: Tach inop
Post by: 86caribbean on November 20, 2013, 04:00:55 PM: Depending on how it was wired, the tach could of encountered a voltage spike and the main bord is damaged now.