Merc blackmax 150 trim/tach question

[Masterbaiter_rios]

Hello all, boat/motor is a 1994 procraft 150vc fish ski combo/ 150 2.0Liter serial #0g043426

I had a voltage spike recently all the way up to 18v which alarmed my hummingbird unit. So I replaced both regs with new oe merc units that are updated with inline fuses in case they crap out your harness doesnt get burnt up. Voltage went back to normal at idle and charging with peak of 14.4 volts.

Well now the problem is when I trim up or down my voltage and rpm drops. I replaced both trim solenoids aswell as the starter solenoid just to be sure. Voltage on my fish finder shows charging at 13.4 when revved to 3k, but volt meter shows 14.4 peak, I know the fishfinder isnt reading correct but that's not a problem I dont feel.

My question is how much voltage drop is acceptable when trimming up or down? At idle trimming up or down it goes from 13.8 to 12.5ish so about a full volt. So when I'm wot trimming up or down my tach starts twitching like its losing voltage signal, could I have 2 bad new regs or a stator going out? Or possibly a trim motor drawing too much amperage? Does that trim tilt sensor on the left side of motor effect anything? Any tips info recommendations appreciated, trying avoid throwing more parts that I dont need at it. Thankyou!

 

[Chris1956]

Power trim uses a lot of power. It will definitely cause a drop in voltage, especially if the battery connections or other connections are dirty or the cables are corroded. However, it should not affect the ign system or the tachometer, I wouldn't think.

I would clean all the wiring connections and be on lookout for corrosion under the insulation on the major wires.

If that doesn't fix it, the PTT motor could be partially shorted causing the power drain. Not sure how to test that. Can you inspect the PTT motor for corrosion? I had one nearly rust thru...

 

[Masterbaiter_rios]

Power trim uses a lot of power. It will definitely cause a drop in voltage, especially if the battery connections or other connections are dirty or the cables are corroded. However, it should not affect the ign system or the tachometer, I wouldn't think.

I would clean all the wiring connections and be on lookout for corrosion under the insulation on the major wires.

If that doesn't fix it, the PTT motor could be partially shorted causing the power drain. Not sure how to test that. Can you inspect the PTT motor for corrosion? I had one nearly rust thru...

Not sure if I can test it I'm gonna take it off and see how it looks, worst case just replace it as it's only $60 I think for oe on Amazon. I checked all the wiring, batteries load Test good. On the regulators it has the 3 yellows, 2 reds, and 1 gray tach. I get the yellows to yellow, but the reds does it matter? They all go to the starter solenoid post anyways so I didnt think so, but wanted to make sure. I cut off all the bullets and waterproof heat shrink butt connectored everything for both regulators.