1989 Carver Santego 2767 RPM Question

[DukeLang83]

I have a Carver Santego 2767 with twin 4.3 Mercruisers. I am not sure if my RPM gauges are showing accurate information. I
cruise at about 28 MPH at 1900 RPM on each engine but when I read some of the other posts it seems that the RPM needs to be significantly higher for me to hit that speed. Are my gauges wrong and is it possible for both gauges to be wrong?

[buster53]

No way you are hitting 28 mph at 1900 RPM’s. Maybe double that would be a lot closer.
Anyway, not an expert on this, but if I’m not mistaken, tachs have a settings button to tell it if it connected to a 4,6 or 8 cylinder engine. Maybe yours is not set for a 6 cylinder engine.

[Midnightsun]

Yep, should be turning at least twice as fast to attain that speed. What is your WOT? Should be 4400-4800 rpm. Your tachs are not reading correctly at all.

Curious, what do the tachs register at idle?

[bud37]

One question from the other direction.......how are you reading the MPH ?

It is true the tachs can be adjusted or need the little screws moved back and forth ( corrosion) to be on the right engine setting but both are the same ?

New boat to you ?

[DukeLang83]

Source of the post Yep, should be turning at least twice as fast to attain that speed. What is your WOT? Should be 4400-4800 rpm. Your tachs are not reading correctly at all.

Curious, what do the tachs register at idle?

At idle they register 7-800. Is that accurate? I don't know about WOT, I haven't gone that fast yet.

[DukeLang83]

Source of the post One question from the other direction.......how are you reading the MPH ?

It is true the tachs can be adjusted or need the little screws moved back and forth ( corrosion) to be on the right engine setting but both are the same ?

New boat to you ?

Yes, new boat to me. The speed is based on GPS. Yes, both tachs show the same. Where would these little screws be located?

[km1125]

Source of the post
... Where would these little screws be located?

They're on the back of the tachs. You might have to slightly depress them before turning, but just turn back and forth several times then put them on the right setting (6cyl) and see if that makes any difference.

[buster53]

Source of the post

Source of the post Yep, should be turning at least twice as fast to attain that speed. What is your WOT? Should be <a href="tel:4400-4800">4400-4800</a> rpm. Your tachs are not reading correctly at all.

Curious, what do the tachs register at idle?

At idle they register 7-800. Is that accurate? I don't know about WOT, I haven't gone that fast yet.

It’s a good idea to open up your engines once in a while even if only a half minute just to know what they are capable of from both the speed and RPM’s. You might be over or under propped and you will now have a baseline to let you know down the road if you are having any issues.