crazy tachometer

[rblatter]

Why does the starboard tach show a differrent r.p.m then the port side one. Mentioned it to our dealer and he said not to worry to keep the engines balanced and all would be well. It just bugs me to see it. Any ideas what is going on.

R.B.:smt021

 

[Hampton]

Depending on the type of boat, engines, and tachs, try accessing the back of the tach. If it has a switch to indicate a 4 or 6 or 8 cyl motor, cycle the switch back and forth a few times and then select the correct setting. See if that helps. They tend to get corroded and wander off the correct setting electronically. That messes up the tach reading.

 

[rblatter]

Thank you for the information. I have a 310, 2001 with 350 EFI, bravo 3s.

 

[NorCal Boater]

I was having the same problem on my 340 plus the needles bounced around. I did exactly what John said and it solved the problem. I checked them recently with an engine analyzer and found they were right on the money.

 

[LifeisGood]

I had the same problem and the fix described above fixed it.

 

[rblatter]

Hi John,
Today

 

[rblatter]

Hi John,

Did exactly what you said and it works like a charm. Thank you for the good advice.
Robert B.

 

[mgingrich]

Had the same problem with my 98 400da.
Seems to be a Sea Ray exclusive.
I bought new digital tachs on line at ebay. they matched exactly, and all is well.

Maury

 

[Walz]

Depending on the type of boat, engines, and tachs, try accessing the back of the tach. If it has a switch to indicate a 4 or 6 or 8 cyl motor, cycle the switch back and forth a few times and then select the correct setting. See if that helps. They tend to get corroded and wander off the correct setting electronically. That messes up the tach reading.

My tachs were off by about 400-500 RPM. Pulled the dash today and did the switch thing. It worked! Now tacks are about 75 RPM off which is within reason. Thanks for the tip! :smt038

 

[Hampton]

Everyone is welcome.

 

[DavidS]

My 290AJ did the same thing and Sea Ray replaced both n/c under extended warranty. They said it was a common problem.

 

[jbiddle]

Adding to this thread, I tried the tip on a 1997 250DA. The back of the tach has a light bulb receptacle, and what appears to be a plastic switch that you could turn with a screwdriver. Is that it? It is not clearly marked 4 6 or 8 cylinder. It has settings like 2p and 6p (unless my eyesight has slipped more than I thought). Is that it?
Thanks.