Tach problem

Dan McNally · Posted: Sun May 09, 2010 10:17 am Post subject: Tach problem

Hi all,
Just a question regarding the tach on a honda 90, it has worked perfectly since new but yesterday it would not give me a reading. Then about an hour in to the trip it began to register but it would not read above 3500 any ideas?

Dan

Sea Wolf · Posted: Sun May 09, 2010 10:33 am Post subject:

Dan-

Assuming the problem is simple, first, check all the connections, particularly that it's grounded fully, before going any further.

It' much more likely to be a connection problem than an instrument failure.

Joe. Teeth

Dan McNally · Posted: Sun May 09, 2010 1:11 pm Post subject:

Joe,
I think you are right, I must have something funky going on from corrosion, because my raw water wash down does not function either. Guess I will get a volt meter and start tracing the leads to see what the problem is.
Thanks for the input.

Dan

BrentB · Posted: Sun May 09, 2010 1:37 pm Post subject:

If you have several electrical connections on the battery, remove them and clean with small wire brush including the battery posts, then coat with a suitable protectant, Inspect each terminal for cracks, poor crimps,corrosion

Jack in Alaska · Posted: Sun May 09, 2010 5:13 pm Post subject:

Dan,
I had the same exact problem on my 22 CD/90 hpHonda several years ago.
It was poor connections on the back of the tach. that was the culprit. I told the tech to replace it and he said that was not necessary. Still working fine.

Dan McNally · Posted: Mon May 10, 2010 8:01 am Post subject:

Jack,
I assume that at the back of the tach you mean at the dash? I will start the process of tracing electrical connections this coming weekend when I have some free time.
Thanks for the replies.

Dan

Fishhawk · Posted: Mon May 10, 2010 8:55 am Post subject:

Back of the tach is likely right.

Same thing happened to me not long ago. From the helm and while watching the tach I just reached around and fiddled with the wires on the back of the tach and found the problem with out even stopping the boat. It was a loose connection.

Dan

toyman · Posted: Mon May 10, 2010 9:46 am Post subject:

The tach on my 150 every so often goes schizoid on me - the instruction I received were to use the internationally recognized method of fixing instruments - thump it. Works every time, settles down like a rock. :thump :thump

jhwilson · Posted: Mon May 10, 2010 11:34 am Post subject:

Had a 90 Honda on my 2002 Lund Alaskan. Once or twice the tach would show almost double the actual rpms. Never could find a connection problem but the "thump" worked each time.

Harper

thataway · Posted: Mon May 10, 2010 11:51 am Post subject:

You need to check all connections--from the battery to the engine, and dash connections. To start with brush those larger connections with a brass brush, spray cleaner over the contacts and work the plugs, finally finish off with corrosion block or a dialectric grease.

BrentB · Posted: Mon May 10, 2010 1:08 pm Post subject:

Anyone have a picture of the tach electrical connections (backside of the tach)? Based on the comments, maybe it can be improved. Mine is solid threaded connector like used for a GPS/Chartplotter.

thataway · Posted: Mon May 10, 2010 4:30 pm Post subject:

Is this a solid connector, or a coaxial cable? If coax--then use contact cleaner and put some dialectric grease on the fitting when you put it back together.

Jack in Alaska · Posted: Mon May 10, 2010 4:49 pm Post subject:

Dan,

Yes I meant on the back of the tach on the dash. Those connections. An occasional thumping would bring it back also but after awhile that failed to fix it.