Tachometers.....

[oscarvan]

They are electric, I got that much. Can anyone tell me where they get their data? Only evidence of RPM leaving the engines are the cables coming off the transmission oil pumps on the front going to the synchronizer.

The book lists 3 possible locations on the rear of the engines but I am not recognizing them from the pictures....

There's a 300 rpm difference between the two, at both helms. Logic says a sender. Would like to swap them if not too involved to see if the issue migrates.

 

[racclarkson@gmail.com]

Swap the tachs first. That's been my experience.

 

[oscarvan]

Swap the tachs first. That's been my experience.

Lower helm and fly bridge agree.... What are the odds of BOTH tachs on the same side being bad? But it certainly won't hurt.

 

[madhatter1]

There is a pulse generator for each on the synchronizer on my boat. Does the synch work? If so then cables are good to synch. Then test pulse generator for AC voltage while running. From there it could be a wire issue. I am dealing with that now as one tach is reading too high.

 

[racclarkson@gmail.com]

Swap the tachs first. That's been my experience.

Yep, missed the both helms part. Are they the same brand and model? Might they have been replaced together in the past? Have you compared the dip switches port and starboard?

 

[oscarvan]

There is a pulse generator for each on the synchronizer on my boat. Does the synch work? If so then cables are good to synch. Then test pulse generator for AC voltage while running. From there it could be a wire issue. I am dealing with that now as one tach is reading too high.

I was wondering about that...... There's not a lot of wiring coming out of it though. I will study the literature....

Robert, all 4 look identical. I will look at the back sides.

This morning left side idle was around 800, right side 450..... but they sounded the same.

Again the synchronizer works.

 

[racclarkson@gmail.com]

I was wondering about that...... There's not a lot of wiring coming out of it though. I will study the literature....Robert, all 4 look identical. I will look at the back sides.This morning left side idle was around 800, right side 450..... but they sounded the same.Again the synchronizer works.

Idle in neutral or in gear? 800 obviously too high. 450 ok in gear, but too low for out of gear, at least in my world. What make are the tachs?

 

[Scarlett]

If they are Aetna tachs there tech support is fantastic. And whoever said dip switches is probably correct, at least it was with mine. John

 

[oscarvan]

OK here we go..... No brand that I can see... And these look from the pre-dip switch era..... I do see a "calibration adjust marking on the back....

Guess I can try the strobe calibration.

 

[racclarkson@gmail.com]

Remove the black rubber disc. Dip switches. They’re Aetnas.

 

[oscarvan]

Excellent. Next question.... what position should the dip switches be, and why would they have been moved on both helms on the same engine?

 

[racclarkson@gmail.com]

Excellent. Next question.... what position should the dip switches be, and why would they have been moved on both helms on the same engine?

As to the first, call Aetna. As to the second, I’m good, real good, but how could I possibly answer that?

 

[oscarvan]

As to the first, call Aetna. As to the second, I’m good, real good, but how could I possibly answer that?

I was hoping you were a claire voyeur.....

 

[oscarvan]

Meanwhile after RTFI it appears that yes the tachs are connected to the Glendinning with what looks like some pretty gnarly corroded connectors. I see room for improvement there.

But first I need to know more about how this works.

Does anyone know if they'll take the time to chat on the phone?

 

[Nick in Manitou]

You might have already received the information you need, but if not, the Glendinning website has their manual available for downloading.

https://www.glendinningprods.com/wp-content/uploads/2017/12/Synchronizer_-_Manual.v1.pdf



Nick

 

[oscarvan]

You might have already received the information you need, but if not, the Glendinning website has their manual available for downloading.

https://www.glendinningprods.com/wp-content/uploads/2017/12/Synchronizer_-_Manual.v1.pdf



Nick

Thanks. Yes, I have that.

 

[Photolomy]

I am not at my boat, but this might help...

1. The glendenning unit is a mechanical device and has two rotating shafts, one from each engine, and adjusts the slave throttle such that the two shafts are rotating at the same speed via a mechanical linkage between the two shafts.

2. These two rotating shafts can be connected to the engines mechanically, using drive cables, or if drive cables would be too long, then using electric motors connected to the engine tach senders to drive the two shafts.

3. ADDITIONAL senders can be mounted on the glendenning unit to drive the tachometers on the boat.

Since your glendenning unit seems to be functional (your boat isn't driving around in circles) then the linkages between the engines and the glendenning unit seem to be ok and the fault is with the ADDITIONAL sender mounted on the glendenning unit and feeding your tachometer(s).

Each shaft of the glendenning unit (upper and lower) is driven by an engine. On one end of the shaft is the mechanism to drive (rotate) the shaft and on the other end is the sender to drive the tachometer.

Glendenning will help in determining what sender you need to buy if this is the case.

Btw, the senders create a pulsing signal and the tachometers convert that pulsing signal to a voltage, proportional to the count, which then drives the needle. The gauges themselves, as are all gauges, are ammeters.

 

[oscarvan]

I am not at my boat, but this might help...

1. The glendenning unit is a mechanical device and has two rotating shafts, one from each engine, and adjusts the slave throttle such that the two shafts are rotating at the same speed via a mechanical linkage between the two shafts.

2. These two rotating shafts can be connected to the engines mechanically, using drive cables, or if drive cables would be too long, then using electric motors connected to the engine tach senders to drive the two shafts.

3. ADDITIONAL senders can be mounted on the glendenning unit to drive the tachometers on the boat.

Since your glendenning unit seems to be functional (your boat isn't driving around in circles) then the linkages between the engines and the glendenning unit seem to be ok and the fault is with the ADDITIONAL sender mounted on the glendenning unit and feeding your tachometer(s).

Each shaft of the glendenning unit (upper and lower) is driven by an engine. On one end of the shaft is the mechanism to drive (rotate) the shaft and on the other end is the sender to drive the tachometer.

Glendenning will help in determining what sender you need to buy if this is the case.

Btw, the senders create a pulsing signal and the tachometers convert that pulsing signal to a voltage, proportional to the count, which then drives the needle. The gauges themselves, as are all gauges, are ammeters.

The above is exactly where we are at. Thank you. The next step is for me to take pictures later today and send to Glendinning to, indeed, determine which add on tach senders I have.

 

[SKYCHENEY]

I believe mine are Sun Tach pulse units.

 

[oscarvan]

So wouldn't you know it..... "it" knows I'm coming with tools. RPM's within 100 of each other for three hours...