1985 Carver 3607 Tach issues

[3607Dave]

I have an issue with the Tachometers on the bridge and lower helm. All 4 of them do not work, the synchronizer gauge on the bridge works. There isn't one at the lower helm. I would think is would be bad ground from the engines some place. The synchronizer gauge works. That right there leaves me If anyone can clue me in how they all work together. That would be a great help. Thanks

[waybomb]

Try this. On the back of the tach is a small selector ( for selecting 4. 6, or 8cyl) you can turn with a small screwdriver. Move it back and forth a number of times.
The contacts may be corroded. This cleans them up. If the synchronizer is getting a signal, so are the tacks.

[3607Dave]

I'll have to give that a shot on the bridge. I did get a real crappy shrink wrap job last winter. The wiring diagram in the manual is useless. Makes sense if the tach signal comes from the bridge, Thanks David

[km1125]

Source of the post Try this. On the back of the tach is a small selector ( for selecting 4. 6, or 8cyl) you can turn with a small screwdriver. Move it back and forth a number of times.
The contacts may be corroded. This cleans them up. If the synchronizer is getting a signal, so are the tacks.

You might have to depress it a little before you can turn it. If it doesn't turn easily first, then try depressing it with the screwdriver before you turn it.

[km1125]

Source of the post I'll have to give that a shot on the bridge. I did get a real crappy shrink wrap job last winter. The wiring diagram in the manual is useless. Makes sense if the tach signal comes from the bridge, Thanks David

The tach signals come from the engines and go to both the lower helm and bridge. At both the lower helm and bridge, you'd have a synchronizer module tied to each tach (if you have the sync gauge... I'm surprise your lower station doesn't have one!)

Since they are in parallel, either station could cause the tach signal to become too low for the tachs to work. The first thing I'd do is disconnect the sync module on the bridge and see if any of the tachs start responding.

Also curious if you could post a pic of your lower station instruments. I though the sync was standard so I'm curious what the dash looks like without it.

[3607Dave]

Going up to the boat tomorrow to go out on the lake. I'll post photos of the upper and lower helm thanks for the tip! David