Tach issue on 6BTA 5.9 – 1996

[Mike Uliasz]

Having an issue with my Star Board tach, getting progressively worst each time out.  Won’t read at start up, but would start reading at 800 rpms, then read at slow idle (600 rpm’s) once warmed up.  Now it’s not reading till I hit the throttle to put the boat on a plan. The port engines has the Dual Output Magnetic Pickup Speed RPM Sensor (TACH) (2 sets of connections).  The port has the single output magnetic pickup.   Does this sound like a magnetic pickup issue (either replace it or adjust it)?   And does SMAR sell the single output magnetic pickup or can I just use a Dual Output Magnetic Pickup and just use one connection? The port engine with the Dual Output Magnetic Pickup has the sync on that side.  I’m guessing that is why it has the dual output? Thanks Mike

Topic

[Clark Leighs]

This is just general.

Make sure that the wiring , at sender AND at the guage,  is tight and free of any corrosion.  Even light oxidation can interfere.    Make sure the guage itself is receiving full 12 v.     It is not just the ground wire but all of it.  Poor voltage to the guage will produce poor results.

Check the sender.   I am assuming you have one at the back of the engine which reads the flywheel teeth as they whiz by when the engine is operating.     The face of the sender must be clean and free of rust flakes which can interfere with the electrical pulses the flywheel teeth create.   Remove it and see, clean it, and reinstall.

Check the depth adjustment of the sender.   If it is out to far  it may not be able to read reliably.  I have dealt with senders like this in different applications and when they are initially set up they read but as they age the range they can sense at reliably can be reduced.    All they need is to be adjusted.   

 

THe adjustment is, ENGINE OFF, to turn it in untill it touches the flywheel lightly, then back it out  about 1/2 turn and reset the lock nut.

See what happens.

 

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Mike Uliasz

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