Tach pegs 10 when trim is used

[Kzaker]

OT153924
200EFI.
Just replaced the regulators with new oem, I’ve never had this issue before but I always had a bad regulator so I’m not exactly sure where I would be crossing/shorting. Doesn’t matter if I’m trimming up or down, the Faria tach goes all the way to 10, and the voltage droppes to around 12v, I didn’t anticipate that much of a draw, that’s why I’m suspecting something is crossed. It still charges at around 14v after my first trip with new regs, I don’t want to burn one up at the tune of $210...

Any advice or direction is greatly appreciated!

Regards,
Karl

[EuropeanAM]

Karl:

Check your battery terminal connections. ENGINE cables first, remaining lugs Largest to Smallest, and finish off the connection with a Stainless Nut or LOCKNUT (do not use wing-nuts).

If still having problems at that point, check wiring connections on instruments (make sure they are clean/tight).

[Kzaker]

Thank you. I will check again as I believe you had just made a note in my previous post to connect engine terminals first, then largest to smallest, which I have done.

Under NORMAL conditions, should I be seeing the voltage draw from 14 to 12v from the trim motor operation?

[EuropeanAM]

On this engine, that is not at all abnormal. Trim pump pulls more current than the charging system puts out (at idle or low RPM's, especially).

It is a high enough draw that there will always be a change in voltage (note that you need to be viewing a DVOM connected directly to the battery for this type of reading... anything running from dash wiring is likely not accurate to start with).

[Kzaker]

Still troubleshooting this.. the tach apparently only does it while the motor is running- I’m not exactly sure why that is.. with ignition on and dash on, tach stays at 0

[EuropeanAM]

That is normal... the other needle jump you described probably is not.