Tach not working

[1sweet63]

I have a 2002 sea ray weekender 225, w a mercruiser 5.0 MPi my tach is not working. Starts out at about 4500 and then goes to 5500 when its running. I believe and hope this is the reason my boat is running in limp mode. Can anyone tell me how to check this on both ends to find out the culprit. Back of tach is getting 12v to all the wires except the one that says snd its not showing any volts at all. The grey wire that leads from it goes to a relay beside the ecm, I believe the relay is still good considering the fuel pump runs off of it and is working. Also any insight on that or why else the boat is in limp mode would be greatly appreciated. All new tune up and oil pressure sender so I know its not that.

 

[JVM225]

Before getting too crazy with it:
There should be an adjustment point on the back of the tach where you can adjust it for use with 4,6, or 8 cylinders.
If it isn’t marked for those 3 things then you’ll see that there are markings on it to indicate a position.
It will look like a screw head. A small slotted screwdriver fits in it.
Make note of the position.
Insert screwdriver and twist back and forth a few times.
Return to original position
This usually cures tach problems.

 

[1sweet63]

Before getting too crazy with it:
There should be an adjustment point on the back of the tach where you can adjust it for use with 4,6, or 8 cylinders.
If it isn’t marked for those 3 things then you’ll see that there are markings on it to indicate a position.
It will look like a screw head. A small slotted screwdriver fits in it.
Make note of the position.
Insert screwdriver and twist back and forth a few times.
Return to original position
This usually cures tach problems.

Already did that, didnt work, plus may I note the digital hours indicator is not on either

 

[scoflaw]

Is that ECM even limp mode capable ? MEFI 3 isn't. 555 yes

 

[1sweet63]

Is that ECM even limp mode capable ? MEFI 3 isn't. 555 yes

Im assuming yes, since the boat is supposed to do 45 at 4500 rpms and will only do 35 and 3500 rpms, with the motor sounding amd running like a kitten

 

[scoflaw]

Im assuming yes, since the boat is supposed to do 45 at 4500 rpms and will only do 35 and 3500 rpms, with the motor sounding amd running like a kitten

If your down a cylinder or 2 it's possible to sound smooth. So what ECM do you have ? If you don't know, post up your engine # If your engine runs up to 3500 rpm, that's not limp mode