DD 4-53 Tachometer issue

[mkh8911]

My port tachometer quit working on the flybridge and in the pilot house. Anyone know how to resolve this?
Thanks,
Kevin

[Captain Ralph]

This forum went thru this for another member a few months ago. Many good points and ideas were brought up.
I believe that final fix was just bad wire connects on the engine sender.

However, your sender could be in a few different places.
Usually on the back of the engine, or the Glendinning synchronizer box. Sometimes on the front crankshaft.

First question to you, When you find your sender and it is not on the back of the engine and the wire connection looks good, does your synchronizer work?
There is a reason for this silly question.

[mkh8911]

I don't have synchronizers. I suppose the trick will be finding the sender. I thought maybe someone here who had 4-53's would know where it's located. Otherwise, I'll see if I can find it when I get back to the boat in a couple of weeks. It surely can't be that difficult to find. Thank you for letting me know about the other thread. I'll try to search it out.
Thanks,
Kevin

[Captain Ralph]

Then your on easy street. Rarely does the mag pick-up / sender fail. Just like your raw water pump, you should find your sender on the other cam end or blower drive end.
Could still be on the front but look aft first.
Send pictures of all if your not sure of what you find.

Now, think back,, what service was preformed rite before the tach's died. Water pump service??

You may also have a electrical issue powering your tachs. Please keep that in mind. Do they move or zero when engine switch is enabled? Volt meter coming up is a help..

[yachtsmanbill]

Off the rear end of the cam is a cable drive to a right angle gear unit. One side of that goes to the cable driven lower helm tach and the other side is a tach generator for the electric upper helm tach. One pic shows the cam end drive with sheared 2 inch long cable... 649736497464975

[yachtsmanbill]

Thats also the NOLA contact for parts as of 2006. Youre welcome...

[mkh8911]

Captain Ralph, I had new raw water pumps installed just before they quit. Thank's for the pics Bill. At least I know what I'm looking for now.

[SKYCHENEY]

I just replaced a Sun Tach sender on a 60C. It was the sender that failed, not the cables or ends. The sync worked fine. So you won't know until you find them and you can always swap senders and make sure that's not your issue before you look into the cables and ends.

[mkh8911]

Thanks everyone for your insight and suggestions. I'll dig into it and let you know what I
find.