Tach Repair
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=460
Printed Date: November-22-2024 at 3:17am
Topic: Tach Repair
Posted By: DDSUPPLY
Subject: Tach Repair
Date Posted: June-08-2004 at 1:57pm
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On my 65 Barracuda -The tach does not work,is there a test I can do to see if it does work and maybe the wire is just broke or loose? Where does the tach wire attach back on the motor?
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Replies:
Posted By: yellowdog
Date Posted: June-08-2004 at 6:40pm
The tach wires into the positive lead that runs from the coil to the distributor. Today's standard is for a gray wire to run from the dist. to the tach, don't have a clue what they did in '65. Check the continuity of that wire first.
Not a lot to go wrong with a tach. But they do go bad sometimes. Unless you want to stay with the original style, replacements are reasonable and easy to install. Matching the original will be hard to do and finding someone to repair an old one may be tougher.
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Caretaker of the wife's '78 Ski Nautique
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Posted By: Rick
Date Posted: June-08-2004 at 10:56pm
I beleive the Tach wire in my 66 is green. It does attach to the + side of the coil
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http://www.correctcraftfan.com/diaries/details.asp?ID=250&yrstart=1996&yrend=2000%20" rel="nofollow - 2000 Ski
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Posted By: yellowdog
Date Posted: June-09-2004 at 4:51pm
DDSUPPLY,
Forgot the most important thing to check! The ground wire. A loose screw, nut or a bit of corrosion on the ground wire or terminal can drive you nuts trying to find a problem.
Another item could be an ignition wire. For a long time boat and gauge manufacturers used just 2 leads for the tach; a 'hot' lead from the distributor and a ground. Somewhere along the line the gauge companies added a terminal that wired to the ignition switch. It's a purple wire today.
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Caretaker of the wife's '78 Ski Nautique
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Posted By: DDSUPPLY
Date Posted: June-11-2004 at 6:17pm
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I checked continuity--it is ok. The rest of the wires have been cut loose. I don't know why. There is a green-black-yellow-brown wire coming from the tach. have tried various combinations. the gauge will peg on one try, so if anyone does know the correct wiring let me know. thanks
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Posted By: Rick
Date Posted: June-12-2004 at 4:56am
Black Ground Green + coil yellow Ign. Brown - Coil Wuould be my guess
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http://www.correctcraftfan.com/diaries/details.asp?ID=250&yrstart=1996&yrend=2000%20" rel="nofollow - 2000 Ski
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Posted By: kenny g
Date Posted: June-12-2004 at 12:05pm
DDSUPPLY page 34 on the chrysler marine manual.wire # t-1 is dark blue goes to a "cowl panel plug in connector" good place to start checking.from thereit runs back to F ignition relay. from relay to + side of coil it shows J wich should be a tan wire and has an in line resister.
wich ? witch which i need to go back to skool.
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kenny g
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Posted By: 66polyhead
Date Posted: June-12-2004 at 9:11pm
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The airguide tach on my 66 is for a v-8 only. the two wire leads are black and brown. It sounds like Rick is on the right track.
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Posted By: SnoPro150
Date Posted: July-27-2004 at 9:01pm
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Is there any way to adjust a tach on a 78 tique. It seems to go up and down right with the RPM but always reads to high even when the engine is not running.
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Posted By: Rick
Date Posted: July-28-2004 at 2:16am
Try turnuing the key on and off see if that resets the Tach. Mine always read 1K after I shut it off until I turned the Ign on then off without starting.
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http://www.correctcraftfan.com/diaries/details.asp?ID=250&yrstart=1996&yrend=2000%20" rel="nofollow - 2000 Ski
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Posted By: David F
Date Posted: July-29-2004 at 3:00pm
SnoPro:
Your tach is bad, replace it.
DDSUPPLY:
Tachs have one or two wires/terminal connections. One is ground, and the other goes to the NEGATIVE side of the coil. If you connect it to the positive side of the coil, you will peg the tach and possibly damage it as it will always be getting line voltage. When hooked to the negative side of the coil, it is measuring the frequency of the coil discharge. This frequency changes if you have a 4, 6 or 8 cylinder engines, so the tach must be proper for the type of engine you have. Some tachs have jumpers on the backside to select the number of cylinders.
Usually, the wire is black from the tach to the NEGATIVE side of the coil. A brown or green wire usually indicates ground.
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Posted By: kenny g
Date Posted: July-29-2004 at 4:19pm
hay david f..could it not also be a bad ground wire to the tach ?
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kenny g
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Posted By: David F
Date Posted: July-30-2004 at 2:30pm
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Yes, absolutely. Good point, always check for good ground first thing when troubleshooting guage problems, especially erratic guage movement.
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