HarryS Posted September 14, 2013 Share Posted September 14, 2013 The tachometer in my '60 B Model (673) started out being off (under) by about 25%.. It now won't go above 800 RPM regardless of engine speed. I tried disconnecting the cable at the engine end and using an electric drill. That pushes the tach up past 3000, but I'm not sure how many rpm's the drill is turning. The square drive on the cable end doesn't seem rounded nor does the drive connection. I'm not sure what to check next. Thanks for any suggestions. Harry Quote Link to comment https://www.bigmacktrucks.com/topic/32767-tachometer-troubles/ Share on other sites More sharing options...
leversole Posted September 14, 2013 Share Posted September 14, 2013 On mine, there was enough "shortness" of the inner cable that it did not fully seat into it's square socket at teh engine fitting...it would act the same as you described...I took it loose from the tach end (it did not want to pull all the way up on the nut, which was my clue that it was not seated at the engine end) and made sure it was seated on teh engine side, started the engine and tried to keep the cable from turning at the tach end, this way I knew it was seated... Quote Link to comment https://www.bigmacktrucks.com/topic/32767-tachometer-troubles/#findComment-205977 Share on other sites More sharing options...
thomastractorsvc Posted September 14, 2013 Share Posted September 14, 2013 On mine, there was enough "shortness" of the inner cable that it did not fully seat into it's square socket at teh engine fitting...it would act the same as you described...I took it loose from the tach end (it did not want to pull all the way up on the nut, which was my clue that it was not seated at the engine end) and made sure it was seated on teh engine side, started the engine and tried to keep the cable from turning at the tach end, this way I knew it was seated... I Vote this the best answer, with age they shrink up and that is a good way to make sure they are seated otherwise you can replace the cable. Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/32767-tachometer-troubles/#findComment-206045 Share on other sites More sharing options...
HarryS Posted September 15, 2013 Author Share Posted September 15, 2013 Thanks for the advice. It sure makes sense. I had hoped to get to it today but didn't. I'll keep you guys posted. Quote Link to comment https://www.bigmacktrucks.com/topic/32767-tachometer-troubles/#findComment-206144 Share on other sites More sharing options...
HarryS Posted September 28, 2013 Author Share Posted September 28, 2013 I finally got to checking the cable and at the engine end it was fine but the instrument end was not tight. When I removed the instrument end to take a look the crimpted on square end was very short and not fully engaged. I was able to get it in and tightened. I took the truck out today and the tach worked great, for about 5 miles and it slipped back to not registering much above 800 rpm. At least now I know that I need a new cable. Thanks again for the advice and vote. Quote Link to comment https://www.bigmacktrucks.com/topic/32767-tachometer-troubles/#findComment-208756 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.