Beede tach is off

[Theoak7]

I have a 2007 31TE with twin 315 Yanmars. My starboard tach has been running a few hundred RPMs lower than the port engine. This has been going on for quite some time and has resulted in the hour meter also being about six hours less on the starboard motor as well. My mechanic has just said its a bad tach and to replace it. I also found that I have a bad alternator so I am wondering if there is anything else it could be

[catalina_mike]

The Beede tach I believe has dip switches that need to be set for the specific engine.

Albin Seward Engine Panel.pdf

[Theoak7]

I checked one tach versus the other and they were identical and it was okay for quite a few years. That's what has me stumped other than it being bad. Unless I'm missing something?

[Jeremyvmd]

Im not sure about this, but where does the tach get its signal on a yanmar?

[catalina_mike]

A magnetic sensor on the flywheel is my understanding. In rereading you post it appears the hour meter is running a bit slow? Verify a full 12 vdc on the ing terminal and gauge ground and tight connections. The only thing the two symptoms have in common is they share the ignition circuit. The reading would not change from previous if the magnetic sensor fell of you would not have any reading. It could be a bad pickup being intermittent I suppose. After verifying 12 vdc I would swap harness from the engines at the dash and see if the problem follows the engine. That would tell you gauge or pickup sender.

[OldDemps]

image.jpg

The Beede tach I believe has dip switches that need to be set for the specific engine.

Albin Seward Engine Panel.pdf

Where are those dip switches? Looks like from your diagram they should be set to; 1,5,7,8,9?

My Beede tach shows slow too. Displays only 2500RPM's at WOT (22knots) but my hour meter seems accurate.

1) Anyone have any Thoughts???

2) while we're at it, my neighboring Beede gauge cluster has moisture under the glass. How do I get that out?

Thanks

[furball]

I called Mack Boring and according to the tech, 6LP has 117 teeth on the flywheel.
Beede manual showed correct pin setting for 117 teeth. I adjust the pins and I'm within 20 rpm of the Flowscan digital tach.
I have been putting a desiccant tub in the medicine cabinet during the week trying to get the moisture out of the gauges. No luck so far.
Let us know if you figure that out.

Thanks,

John

[catalina_mike]

You will never get it dried out using descant in my opinion the dash is far from sealed so more RH% air will always be coming in. Use a small light that will produce heat to dry it out.. You might try covering you gauges if you don't do that now. The moisture is from condensation just like on the outside of a adult beverage. The air is always moisture laden so rapid heating and cooling of the glass gauge lens will allow condensation to form. A fan moving air in the cabinet might also help dry it out.

Tach installation.pdf

[zinbaad]

My 31te has the same tach issue, with approx. 600 hours starboard engine is 6 hours off. When I bought her at 180 hours tach was off 1 1/2 hours

[OldDemps]

Mack Boring tech, 6LP has 117 teeth on the flywheel.
Beede manual showed correct pin setting for 117 teeth. I adjust the pins and I'm within 20 rpm of the Flowscan digital tach.

Great info.

The "Albin Seward engine panel" diagram above says 116 teeth is set to 1,5,7,8,9
1) What is the setting for 117 teeth?
2) Any way for me to confirm how many teeth my (year 2006) 6LPA-STE has??

Either way my tach is set way off with only 6 and 10 set to open (photo attached) and I'm sure that's why it's reading so inaccurate (low).

Thanks!

[catalina_mike]

Rotate it manually after marking one with red nail polish. Way too much work.. Set them per the documentation and call it good.

[OldDemps]

Agreed. Good enough. I set the tach to 1,5,7,8,9 and problem basically solved. Looks like it reading slightly high but much wider scale for monitoring engine performance. RPM now range between 0 to 4000 where before was only 0 to 2500.
THANKS for the knowledge share. I never would found that on my own. I hate electronics.

[catalina_mike]

Pleasure.. My day job is electronics for buildings..

[Theoak7]

I had the settings correct and for the proper amount of teeth at 117 and the hour meter was still off by about 6.5 hours and was about 600 rpms off so finally on Saturday I just changed out both tachs. they are now spot on at idle and about a 100 rpm difference when I get up at about 3000 rpm which I can probably adjust out but overall much better.