Yanmar electrical problem.

[Mika1]

Is there a tutorial on how to bypass the existing wires to the pushbutton with new wire? (Yanmar 2GM20F)?

The distance from my engine to the starter button is about 4 feet, yet my Raspberry Pi restarts whenever I start the engine (running off the same bank). I assume that could be due to the poor wiring issue.
I am not sure If fixing the wiring or adding the starter solenoid is the best fix.

Greg

In my experience if any of your electronics reboot when you start the engine it's probably because they're pulling their power from the start battery instead of the house battery.
A starting battery, when you hit the button to start the engine, will temporarily drop down to something like 9-11 volts even though it's showing 13+ while at rest. A starter draws a massive amount of current for the few seconds it's turning the engine over and that draw will pull the battery voltage below the minimum threshold of the electronics involved - thus, they reboot.
Simple troubleshooting, simple fix: Turn your raspberry pi on then go to your start battery and pull one of the battery cables off. If your electronics shut down, they're wired to the start battery and you need to move them to the house bank. Hope this helps!
P.S. If you don't have separate start/house batteries, replace your battery cables. They're probably ~20 years old anyway. And when you do, look up an ampacity chart or cable sizing guide. Bigger is better as it will minimize the voltage drop and that'll be better for both your starter and your electronics.

 

[Jim Legere]

I am surprised that no one has mentioned the 30 amp fuse, just to the right of the starter in the schematic diagram posted by @jjgrizzard. This fuse is housed in an in-line, non-waterproof holder in the wiring harness, near the harness connector. Corrosion in the fuse holder will cause the intermittent engagement of the starter motor. Cleaning the contacts here (and the wiring harness connector while you're in there) will restore reliability. Nothing wrong with the Cole Hersey solenoid and new wiring either, just a lot more work.

 

[Marmalade]

Have a Legend 37 as well, and took a slightly different approach. I read lots of these threads on running new wires or a booster relay, but thought I'd experiment with something a little different.

I took a 500A winch solenoid with remote, and wired it directly to the starter solenoid. I'm basically just using it as a remote switch as a 2nd parallel button to the push-button on the panel, but saved me pulling new wires to the panel. So the push button still sort-of/almost works.

Works great for me, don't know if it's the best idea. Was cheap and supposed to be weather proof for life exposed to the elements on a vehicle. I sail on fresh water... so we'll see the long-term, this is year 1.

I Keep the remote at the helm. Engine starts immediately. I'm obviously only using 1-side of the relay... and I've contemplated wiring the other side to an actuator to kill the engine... but maybe someday.

 

[east coaster]

I use an ACR in the circuit, it ensures my house bank stays charged as well as taking care of my separate start battery. However there is a feature people may not be aware of and that is the isolation feature. If connected to the start battery as per the wiring diagram on the package, it will isolate the house bank from the short but high amperage draw that can cause your electronics to power off or perhaps cause a power surge to them. Since installing and wiring in the full functions of the ACR I have never had a problem with my electronics dropping out during engine starts. Of course you can do this manually, start the engine then turn on all the electronics after the voltages have stabilized. To me, it is well worth the 100 $ the Blueseas ACR cost. Again your boat, your choice.