It's 5 degrees. Started tractor to move snow. Tachometer went wide open and stuck and there's a howling that appears to be under the dash cowling. Could it be the tach? I'm not sure how it is driven or operates. Everything else works.
B2910 Howling under Dash Cowling
- Thread starter 1011hans
- Start date
I have a B2910 and always figured the tach is mechanically driven, since it counts hours by engine RPM, and not linear time like an electric hour meter would.
Sounds like you may have a broken cable that feeds the tachometer, and you may be hearing the ends rubbing against each other.
Just a guess... Does the howling sound change tone with engine speed?
Sounds like you may have a broken cable that feeds the tachometer, and you may be hearing the ends rubbing against each other.
Just a guess... Does the howling sound change tone with engine speed?
ken erickson
Well-known member
Equipment
B7100 hst, 2650 front mount snowblower, L2501 hst qa loader
I had a 69 Dodge Coronet and when driven in the cold the Speedo would peg at 120mph and make what I would describe as a howling sound. The drive cable was not broke but needed to be disassemble, cleaned and re-lubed. I chalked it up to the old lube had thickened especially when cold.
If the tone changes with engine RPM my bet would be a broken cable...Just relying on experience from so far in the past that I can't remember the details. Do remember the broken cables though...but not what they were from...LOL...but true...
Memory fades as your get older...except for those memories related to encounters that I can't mention to my wife, which occured before we married of course...LOL
Russell King
Well-known member
Lifetime Member
Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
If you disconnected the cable and the howling stopped…. is that a solution which pleases you? …or do you prefer your tachometer to work properly…?? (I’m trying to discern from your last post what you meant.
Did you disconnect the cable…the howling stopped …(because the tach is no longer driven by anything but it also no longer works at all?)
Mechanical tachs which are driven by speedometer cables are internally made up of a gear-set which spins a slip-clutch…which is either magnetic or fluid-drive. If magnetic and the clutch is failed it will produce a “howling” sound….and may either over-speed the indicator….or the indicator may freeze at any position. Disconnecting the cable will stop the sound…but it also does not fix the problem. The problem is the tach needs cleaning/repair. There are instrument shops that can make that repair. (We do it all the time with aircraft mechanical gauges. A shop well-known for repairing all kinds of instruments is http://keystoneinstruments.com/ They specialize in aircraft instruments but they have been known to take interest in restoration of old automotive instruments. They repaired the engine instrumentation of my ‘51 Studebaker about 30 years ago and it still works perfectly.)
If it truly is the cable only… a new tach drive cable would resolve the issue…and in any case (hopefully this is rather obvious) ..a drive cable is required to operate the tach.
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I took the OP's reply to mean the sound stopped when he removed the tach cable from the engine, and he assumes it is a broken tach cable.
But it could also be a damaged tach, that jammed up, and caused the cable to break.
The OP may be able to pull the internal piece of the cable which drives the tach out of the cable to find if it is broken or not. I would think if the tachometer was functioning normally, it should return to zero when the cable was not turning. If the tachometer needle is still at max, this in my mind would indicate the issue is likely within the tachometer itself and not the cable. Even if the cable is broken.
If the cable is not broken, this would also indicate the issue is likely within the tachometer.
Look forward to hearing what the cause of the problem actually turns out to be.
Edit: I guess I am just repeating what GeoHorn said in a different, more simplistic way...LOL
But it could also be a damaged tach, that jammed up, and caused the cable to break.
The OP may be able to pull the internal piece of the cable which drives the tach out of the cable to find if it is broken or not. I would think if the tachometer was functioning normally, it should return to zero when the cable was not turning. If the tachometer needle is still at max, this in my mind would indicate the issue is likely within the tachometer itself and not the cable. Even if the cable is broken.
If the cable is not broken, this would also indicate the issue is likely within the tachometer.
Look forward to hearing what the cause of the problem actually turns out to be.
Edit: I guess I am just repeating what GeoHorn said in a different, more simplistic way...LOL
I replaced the cable finally, it was not broken. Now the tach is erratic. Guess that means the tach is bad.