Tachometer setting

[StanKromfols]

I took my Sea Ray 176 out today for a trial run. I have the 3.0 Alpha One . At idle the tach registered right around 600 RPM, which I believe is correct. With myself (200 lbs) and my friend (170) on board at almost wide open throttle the speedometer showed 48 MPH and the tachometer only showed 2,100 RPM. I have a 19P 3 blade aluminum prop.

There are different settings on the back of the tachometer and I don't know which setting I should be at for a correct reading on the Tach. Has anyone else got this set up and if so can you tell me what setting your tach is at ?

 

[boatrboy]

I don’t remember the settings but I do remember that when tachs start acting erratic putting a small screwdriver back there and rotating back and fourth usually cleans something and the tachs often work perfect again. I have done this on my first boat with luck.

Also - just guessing here but I’ll bet the 4c where it sits, is for 4 cylinder, which would be correct. If that’s so, move it back and fourth and see if it fixes it.

 

[StanKromfols]

Thanks Boatboy, I'll try changing the settings, but 4C was where it was previously and it showed 2,000 RPM when idling, so I don't think that was the correct setting.

 

[Soulshine]

It is the correct setting but if the switch's contacts are dirty you'll get funky readings.

By cycling that selector back and forth you'll clean those contacts. Just put it back to the setting that corresponds with the number of cylinders and you should see results.

 

[boatrboy]

While I would not switch it running, and this video shows a little different situation, it seemed to work..

 

[GypsmJim]

Read the dial and find the manufacturer of the tach.

Go to their web site and find the specs for your particular engine.

Set the switch accordingly.

My SeaRay was usually set for an I/O but I bought the OB. Obviously, the builder guy didn't set it up right because the rpm readings made no sense. I did as above and put it right and viola I'm in bizness.

 

[techmitch]

Read the dial and find the manufacturer of the tach.

Go to their web site and find the specs for your particular engine.

Set the switch accordingly.

My SeaRay was usually set for an I/O but I bought the OB. Obviously, the builder guy didn't set it up right because the rpm readings made no sense. I did as above and put it right and viola I'm in bizness.

I'm surprised that the dealer didn't correct that after the pre-delivery sea trial.

 

[GypsmJim]

I'm surprised that the dealer didn't correct that after the pre-delivery sea trial.

Pffffftttttt. I'm not surprised. Where can you get anything done right these days?

 

[StanKromfols]

I like the idea of checking the dealer web site to see if it gives me the right setting. Thanks

 

[Blueone]

It is the correct setting but if the switch's contacts are dirty you'll get funky readings.

By cycling that selector back and forth you'll clean those contacts. Just put it back to the setting that corresponds with the number of cylinders and you should see results.

You have to be kidding me….. I was about to replace mine and I tried this today and it looks like it worked…. At the dock anyway…… major improvement.…. Time will tell but thanks for sharing

 

[Soulshine]

You have to be kidding me….. I was about to replace mine and I tried this today and it looks like it worked…. At the dock anyway…… major improvement.…. Time will tell but thanks for sharing

I'm glad it worked and surprised that it was new to you. There have been many threads here on the subject and that's where I learned that trick.

While you're in there you can calibrate them too. I connected a remote digital tach once warmed up and choke open and adjusted my tachs to match through that tiny hole in the back of the gauge.

 

[Scott215]

Same thing happened to my boat with an eight cylinder moved it back and forth a couple of times and it fixed itself