2002 380 DA dual 8.1 engines-Tachometer jumping

[Johnny Blades]

Hi all, Just got an 02 380da last month. I am starting to experience this problem and was wondering if anyone knows anything about this. Port side engine tach is going crazy. It shows slightly higher than starboard at idle and gets worse at cruise.
A typical instance: Starboard side will be at 3200 and port will go as high as 4500, yet the engine does not sound like it is over-revving at all, and the boat remains in a straight line.
I have tried swapping the grey wires between tachs (behind the gauges) and the port engine is still showing hi-revs, ruling out the gauge. I think it's a little strange too that the starboard engine has 390 hrs and the port side has 190hrs.
The port side tach was changed some time ago by the previous owner..
Any advice would be greatly appreciated. Thanks.

 

[Pseudomind]

I would clean the contacts first, to include pulling the two cable connectors off of the tachometer sync module and clean them. You have to remove the gauge panel and then look down behind it almost in the center, where it is screwed down. West marine has a spray electrical contact cleaner. I loosened all of the contact connectors and sprayed some of this on them and then re tighten.

Mind has just done this only it was the reverse to what you are experiencing. Port 3200, starboard creeping up to 4200, 4300, 4600.

I have been told this is a normal occurrence for stock sea Ray Tachometers.

Prior to this my sync gauge would read center line if the starboard engine was not running, once you started the starboard engine it would then peg to the far left. If you raised the throttle slightly it would try to peg harder to the left. I cleaned the cable connectors and the contacts they plugged into on the sync module and this quit. It went back to working normally. As to the starboard tachometer, I will have to check on the next outing.

It was the tachometer only and not the engine, as the boat would track straight and there was not increase in sound (rev's) from one engine to the next. Gauge just started climbing higher

If anyone else has more information I would be interested in hearing about it

Thanks

 

[Two Peas]

I'd recommend upgrading your boat to SmartCraft gauges asap. Since I've done so all of this tach fluttering nonsense has disappeared. There are a ton of benefits on top of that.

Total cost was around $800, was an easy DIY job, and makes the boat look way more up to date.

Do a bunch of reading here on CSR - there is plenty of info to make you understand what's involved.

 

[Pseudomind]

I'd recommend upgrading your boat to SmartCraft gauges asap. Since I've done so all of this tach fluttering nonsense has disappeared. There are a ton of benefits on top of that.

Total cost was around $800, was an easy DIY job, and makes the boat look way more up to date.

Do a bunch of reading here on CSR - there is plenty of info to make you understand what's involved.

can you expound a bit on the details regarding the Smart Craft gauges? Example, did you do just tachometer gauges or a Smart Craft display of some type.

Where did you get a blank gauge panel without holes pre-cut in it?

 

[Two Peas]

I have all new Smartcraft Tachs, 4-in-1's, and an SC5000. The blank panel (with cutouts from the factory for the Smartcraft gauges) came from Ken at FP Marine. He is a great guy and very helpful.

Read away...

http://clubsearay.com/forum/showthread.php?t=27511

http://clubsearay.com/forum/showthread.php?t=27039

 

[Southpaw II]

Simply remove the panel and move the switches on the back of the tach. This is the switch that changes the setting from 4, 6, or 8 cylinder setting. Just switch it back and forth about 5-6 times. This cleans the contacts, and the problem should be solved. This corrected the issue on my boat.

 

[Warren]

You have established that: (1) the port tachometer is OK by switching the terminals port for stb. and (2) you have also concluded that the port tach was already replaced 190 hrs. ago.

As Pseudomind suggested cleaning the terminals is a good suggestion, but it is likely that you have already done that in changing the leads on both tachs. He also mentions checking the terminals on the "tack synch module" something which you might NOT have checked. It is, as he mentions, installed under the dash forward of the synch guage somewhere (all models are different) close. It looks like a black hockey puck, black in colour and round in shape.

If the synch guage is also unreliable (you don't say either way), with the synch needle moving randomly or stuck at one side or the other, you may need to replace the module - usually less than $80 and generally supplied by Teleflex Morse with different models for gas and diesel. Most marinas can supply this item or you can order direct from TM as I did - and it fixed my synch guage problem immediately.

However, if the synch is operating normally and only the port tach guage is irratic - after you have cleaned/checked terminals and flipped that switch as suggested above - a new tach may be the only answer. The Sea Ray ones are very basic and prone to failure. Check out the digital models if it's in your budget.
Warren

 

[terminaldegree]

Southpaw II's approach has worked well for me on at least 4 boats, fwiw. Luckily, never had to replace a tach, but have had to replace a couple of other gauges in the past.