Tachometer problems, need suggestions

[Diver Down]

My port tach (salon helm) has not worked in a year and I finally got around to troubleshooting the problem. Turns out to be a dead signal generator, not a broken tach. The local Detroit diesel folks told me yesterday that the piece (new part) has not been available for about 16 years. I bought a SW signal generator yesterday which apparently has a different pulse, as the tach readings are off by at least 200 rpm. I can replace the original, unbroken tach with a SW unit but would rather not have two different tachs on the same helm.

Any suggestions? Anyone know where I might find a used tach signal generator?

[MikeP]

If it was me and I could not come up with a used generator, I would just bite the bullet and replace both tachs/generators. There's no way I could deal with two different tachs at the same helm station!

[sgharford]

Just another possible option for pulse generator, Teleflex Signaflex IA96042. I can't say it will work any better then the SW as I replaced my gauges with Teleflex Heavy Duty series at same time. I remember the replacment Teleflex tach, had a selector switch on rear to compensate for gearing of pulse sender RPM compared to engine rpm (1:1, 2:1, etc). If you are only off 200 RPM it's possible you have a funky ground. I think best way to test what is what is hook the new sender up to the OTHER tachometer and see if it's off 200 RPM as well. Maybe you don't even need to do this - you mention it's your Port tach in salon helm, so is Port tach in FB helm reading correctly? If so, then I would say your gauge or possible ground to port salon gauge is messed up.

I had allot of trouble with my port engine tach, turned out to be what I believe was alternator sending funky pulse out of it's own that would sporadically freak out my tach thru the ground wire. Problem plauged me for years, a 2nd replacment tach and pulse generator didn't solve it. After I replaced alternator and voltage regulator with larger model the problem went away. Good luck, hope someone can come up with exact answer for you.

[sgharford]

Just thought of another thing - make sure the pulse generator it sitting squarely over the mounting hole. If the tang that drives pulse generator is not Exactly centered, it can give you funky readings. I remember I had to adjust existing mounting bracket on one engine when replaced so this happened. I have Cummins 903's. so not sure what your Detroits look like, but thought worth mentioning.

[bobk]

Check with Lauderdale Speedometer. They make the signal generators that Glendining uses and may be able to handle your problem.

Bobk

[Bugsy]

I posted on my "discovery" a while back. Lauderdale Speedo confirmed that the generator should be connected at the engine and not at the synchro.

I switched and eliminated my tach issues.

[GJH]

If you put the generator on the the engine, then how did the synchro hook to the engine? On the Glendinning synchro, cables from the synchro go to where the generator originally screwed in, via an adaptor, and the generator screws in to the synchro. I got Aetna generators from Lauderdale Speedometer to replace my old metal Suns and they fit and work perfectly; one of the easiest fixes of all time.