Rev counter stopped working.

[Leemc]

Thanks Tony, I have no idea about the electronics and science stuff, just what happens with ours as a result. Is cruising with keys in/ out something that people have opinions about?

[Tony Brooks]

55 minutes ago, Leemc said:

Thanks Tony, I have no idea about the electronics and science stuff, just what happens with ours as a result. Is cruising with keys in/ out something that people have opinions about?

 

On a typical setup keys in and turned on whilst cruising otherwise you won't have an oil pressure or temperature gauge working and on most alternators the charge light will glow even if it does not light up completely. If you have a "boy racer" style (cheap and coloured bands) voltmeter that may not work as well.

 

Edited to add. Depnnding upon type and how it is wired a boat with an electric stop control might just stop when turned off or the stop may not work. Beta are good at the latter. The former is fairly rare on boats.

Edited January 9, 2022 by Tony Brooks

[Doug_]

I have a boat with a Beta engine. My rev counter and hour counter packed up about five years ago. The rev counter has since started working but not the hour counter. No amount of wire checking has resurrected the hour counter so I bought an engine hours counter off Ebay and wired it to the ignition switch.

[Iain_S]

2 hours ago, Doug_ said:

I have a boat with a Beta engine. My rev counter and hour counter packed up about five years ago. The rev counter has since started working but not the hour counter. No amount of wire checking has resurrected the hour counter so I bought an engine hours counter off Ebay and wired it to the ignition switch.

I did that, and then got round to fixing the original, using one of these. Seems to be put together a bit better than the original, and working fine, but comparatively early days still ...

[Slow and Steady]

On 09/01/2022 at 12:27, Tony Brooks said:

 

That is to be expected because the instrument needs a +, - and pulse feeds. Remove the + and it stops working, often sticking at the point the + feed was removed.

 

I am not clear if the OP has had  a good look at the + and - feeds to his rev counter. A loose connection on any oen of the three cables  could easily cause intermittent operation.

I have 12v measured between the two.

[Tony Brooks]

7 minutes ago, Slow and Steady said:

I have 12v measured between the two.

 

So that suggests an intermittent or permanent loss of pulses from the alternator. The rev counter pulses are half wave rectified output from just one of the three generating coils so you can lose the pulses while the other two coils continue to charge, be it at a lower current and lower maximum voltage. Once you are sure all the cables and connections on the pulse wire is sound then suspect the alternator. It's the wrong time of year but solar or shore line chargers that produce a higher voltage than the alternator can cause the alternator to shut down, but once the other charge source has been removed a load put on the batteries it should come back on. However, so far a bad connection is more likely.

[robtheplod]

On my boat (also with Beta), the Rev counter often doesn't work until i go pretty much full revs briefly, then its fine for the rest of the trip... very odd....

[Slow and Steady]

1 minute ago, robtheplod said:

On my boat (also with Beta), the Rev counter often doesn't work until i go pretty much full revs briefly, then its fine for the rest of the trip... very odd....

Maybe you have a dicky alternator that refuses to excite without a lot of revs?

[robtheplod]

1 minute ago, Slow and Steady said:

Maybe you have a dicky alternator that refuses to excite without a lot of revs?

that could be it as the charge indictor stays below 14v until i do the same!

[Slow and Steady]

45 minutes ago, robtheplod said:

that could be it as the charge indictor stays below 14v until i do the same!

I just read this on another thread with a completely different subject... Might be interesting for you.

 

 

"Yes you can disconnect the warning light wire and this will probably stop the alternator from starting, but it won’t stop it once the engine is running. And residual magnetism in the rotor might cause it to start working anyway, at high rpm."

Edited January 10, 2022 by Slow and Steady

[TheBiscuits]

47 minutes ago, robtheplod said:

that could be it as the charge indictor stays below 14v until i do the same!

 

A slipping/worn belt can do the same.  Is yours sound and tight?