tachometer issues

[RSC]

Today for no reason the needle on the tachometer on my R21-EC went and kept fully buried. The tach worked perfectly for the first hour of the trip and then went to the maximum. The hour meter also went blank. Any suggestions on a cause? A ground issue? Sender issue? wiring issue??? Any suggestions as to the cause and fix would be greatly appreciated.

 

[SGIDAVE]

Today for no reason the needle on the tachometer on my R21-EC went and kept fully buried. The tach worked perfectly for the first hour of the trip and then went to the maximum. The hour meter also went blank. Any suggestions on a cause? A ground issue? Sender issue? wiring issue??? Any suggestions as to the cause and fix would be greatly appreciated.

Hello RSC,

To help you better please share more info like model year and hours on engine, and MAKE of engine. The 21EC is Yanmar until the MY 2014 when Volvo became the engine used by Ranger.

An older boat may have a BAD tachometer or corroded wire terminal/s while a new boat would more likely have a loose wire.

I see from your posts last month you saw Marc Grove at the Boat show. If you purchased from him then I would call Wefings as they provide outstanding service.

Let us know how it turns out,

Fair winds and accurate tachometers,

dave

 

[elly]

I have had this happen on my R25 w/ yanmar 110 that has an engine stop/kill button. If I turn the key to the off position then on position quickly, the engine does not stop but the tach needle goes to 0. Then if I turn off the engine with the kill button and restart the engine the tach operation is normal. This has happened several times, I don't know why.

 

[RSC]

Dave,
The engine is a 2007 Yanmar 3YM30 with approximately 50 hrs on the engine. As you can see the engine never got much use prior to my recent ownership. It had always been a New England freshwater boat and now resides on brackish water on the coast of Florida. I went out tonight and fiddled with the key switch a bit after reading Elly's response to my question. Initially, the tach needle was stuck on full RPM with the engine off. I turned the key back and forth a few times without starting the engine and the needle dropped back to the 0 position again. Since the boat is on a lift out of the water, I didn't start the engine to see if the tach worked properly again. I will do that tomorrow when I can pump water. I am sure there is a simple answer / fix to the problem as it must not be completely unique to me.

I wil also check with the Yanmar dealer in Cocoa, Fla on Monday about possible causes

Bob

 

[RSC]

I ran the boat for 4hrs today and the tach worked fine...to problems!!! The visiting gremlins had the day off. I will speak to the Yanmar folks on Monday to see if they can figure out what happened and report back.
Bob

 

[daviduphoff]

I too have had intermittent problems with the tachometer and hour meter on my 21 with the 3YM30. Most of my problem has been with the hour meter. Some days it will let you know the number of hours and some day it displays nothing. I have never been able to figure it out and have posted about it before with no solution. Good luck keeping the gremlins at bay.

 

[Tugalong]

For the last 12 months our tachometer has been reading 750 rpm high all the time. I posted for suggestion last April but so far none of the previous or these suggestions have worked.
We have a 2010 R21EC With 3ym30 Yanmar. We have the standard Ranger/Yanmar instrument panel.Sometimes the tachometer needle is at zero or sometimes at 750 with the engine turned off.
A week or so before the problem we replaced both batteries in the tug, so I don't know if this is related to our problem.

Any other suggestions ?

Thanks

 

[tuggertoy]

We have also had intermittent issues with the hour meter display going blank on our 2006 R-21 Classic with a Yanmar 3YM20. It seems to be associated with damp weather but I have yet to find the cause. Eventually the hour meter display comes back to life without having lost track of the hours we have run while it was blank.

If anyone solves this mystery I will be intersted to hear the cause.

Eric
Tugger Toy
2006 R-21 Classic

 

[bymiller]

I have the same problem with my 2007. Yanmar motor with about 1600 hours on it. Initially the hours would be blank. The window where the hours appear would still be backlit, just no numbers. This has progressed over the last year or so from an occasional problem to where I never see the numbers on my 6 or so trips. It does seem to keep track of the hours, just doesn't display them. All other electrical functions on the control panel seem to work. Over the time I have owned the boat I have seen the tach peg at full R PM's or not go to zero when the engine is shut down. Neither of those things have happened for the last year or so

Today I disconnected the plug on the back of the tach and the plugs on both ends of the wiring harness. All were tight and the contacts were shiny. I sprayed all contacts with contact cleaner and still no reading.

Replacing the control panel is out of the question for now as Yanmar wants 500 - 700 for a new one. I am seriously considering getting a small digital hour meter and just sticking it somewhere.

From lack of responses I'm assuming nobody has found the problem yet.

By
Daycare

 

[Two killicks]

Today, three littles things went wrong on board. First our anchor was stuck on the bottom with another anchor that was left by another boat. We could not retrieve the anchor, so I tried to reverse by increasing the rpm slowly but stronger than usually in four different angle with the boat and applied power in reverse but the anchor could not be freed. I then dove but could not reach the anchor. We finally cut the line and left. Soon after While underway, I noticed that the RPM needle was very high! but the actual RPM on the engine was low. So I turned off the boat and restarted to reset the display and the RPM gauge was fine again, but then I noticed that the engine hours meter was flickering for the rest of the day. Could this have something to do with the boat working a little harder to free the anchor in reverse? I must say that It was humid in the boat, I hope that It is just a humidity issue like in the previous post and that I did not dammaged anything... The engine and transmission were doing fine as usual all day after that... Any thoughts? I have the Yanmar 3ym30 engine.

Thanks

Pat