Engine won't start with the key - but with wire

[andreas.mehlin]

I have had my engine (Yanmar 3JH2) out of the boat for a couple of years...and installed it recently. All cables has been replaced and I ditched the old extension wire harness and wired it with my own black and red cables, marking each of them.

Hooked up the last things yesterday and tried to start it....but no. Nothing. Not a sound. The electric shutoff switch worked (connected to a actuator)...and the buzzer alarms went on when I turned the key to on....but to start the engine...Nothing. I then discovered that the cable (negative) going to my relay wasn't connected to the key switch on the panel. That should solve the problem.... Connected it...but still no sound. I took that negative cable and pushed it to the connector next to that stud (which is supposedly closing the circuit when the key is turned). Yes then the engine starts. When I tried to have the key turned to “on” my trick didnt work...and not when turning to “start”. Only worked when the panel was off.





Second problem...there is NO voltage added to the circuit/battery when engine runs. So is the alternator dead? Is this causing the engine not to start, some kind safety feature?

When turning the panel to “on” the buzzers starts and oil pressure and water temp gauge is going to max. Is that normal?

I had the engine started outside the boat last year...standing on a pallet. But I never connected any cables between battery and the alternator. Did run it a couple of times, but never longer than 10 minutes. Did the alternator got damaged?

[gleason99]

More than likely with no battery connected to the alternator you fried the diodes, never start a motor without some type of load on the alternator!

[SteveSails]

If the alternator is internally regulated, which it most likely is if it is the original Yanmar, then I doubt the alternator was damaged. With no battery connected to the alternator the regulator would never turn on.
As for your other problems you say you ditched the original cables and made your own. Find a wiring diagram for that engine and get out your multimeter, start tracing your wiring to the diagram. Verify all the wiring is correct then look for problems with the key switch, starter, and alternator.
Good luck.

[andreas.mehlin]

Well, I can for sure say that I have used Yanmars wire diagram, haha. Without that it would have been a total mess....but of course there can be faults made along the way.

I managed to solve the problem with the key to start the engine, and also so the stop button work when it should. Had made a very stupid fault connecting the relays

Although, Oil pressure and water temp gauge is maxed out when panel is turned on. Also, the RPM gauge doesnt move. Maybe the sensors are all bad? Or something else...

Another problem that occurred. My Simarine Pico battery monitor system says the alternator is drawing 30 Amps!!! Not charging, Drawing. It says minus -30 amps, but also showing a higher voltage. Would this just be a monitoring issue where the numbers are mixed up plus/minus? The monitor displays correct when the fridge is running etc. Also, the regulator output from the solar panels are connected on the same busbar as the output from the alternator. So in-/output current are entering the same stud on the shunt.

[jimbunyard]

Sounds alot like you have a ground and a hot reversed on one of the gauges.

[SailRN]

Originally Posted by SteveSails

As for your other problems you say you ditched the original cables and made your own. Find a wiring diagram for that engine and get out your multimeter, start tracing your wiring to the diagram. Verify all the wiring is correct then look for problems with the key switch, starter, and alternator.
Good luck.

Good advice, and good luck.

[WoodenKetch]

Something is grounded that shouldn't be. Pegged gauges means short circuit. Careful or you will let the smoke out...

[MJH]

Originally Posted by andreas.mehlin

I have had my engine (Yanmar 3JH2) out of the boat for a couple of years...and installed it recently. All cables has been replaced and I ditched the old extension wire harness and wired it with my own black and red cables, marking each of them.

Hooked up the last things yesterday and tried to start it....but no. Nothing. Not a sound. The electric shutoff switch worked (connected to a actuator)...and the buzzer alarms went on when I turned the key to on....but to start the engine...Nothing. I then discovered that the cable (negative) going to my relay wasn't connected to the key switch on the panel. That should solve the problem.... Connected it...but still no sound. I took that negative cable and pushed it to the connector next to that stud (which is supposedly closing the circuit when the key is turned). Yes then the engine starts. When I tried to have the key turned to “on” my trick didnt work...and not when turning to “start”. Only worked when the panel was off.





Second problem...there is NO voltage added to the circuit/battery when engine runs. So is the alternator dead? Is this causing the engine not to start, some kind safety feature?

When turning the panel to “on” the buzzers starts and oil pressure and water temp gauge is going to max. Is that normal?

I had the engine started outside the boat last year...standing on a pallet. But I never connected any cables between battery and the alternator. Did run it a couple of times, but never longer than 10 minutes. Did the alternator got damaged?

I had a similar situation this summer. Came into the dock OK. Completed my business and the engine would not start with the key on departure. A friends 12V jump starter would start the engine but not the key switch which I replaced. At first it still would not start but after reinstalling the new key switch a couple of time, success. That makes me wonder if the old key switch is actually OK and it was simply a wiring issue on the old key switch. Oh well, it is running and I'm not about to take it apart again.

Good Luck.

~ ~ _/) ~ ~ MJH

[Peterbreit]

First problem, when you turn the starter switch to start and nothing happens it means no power or low voltage issue. Which is common on Beneteau because of the distance from the engine panel to the starter on then engine. I don't think your starter switch is bad. You may have to install a small relay.
2. problem with No RPM showing. Yanmar engines connect the tachometer lead to the fly wheel housing not the alternator.

[Jorge M]

Originally Posted by SailRN

Good advice, and good luck.

Check if the new wires are of the same amperage as the originals

[andreas.mehlin]

Originally Posted by Peterbreit

First problem, when you turn the starter switch to start and nothing happens it means no power or low voltage issue. Which is common on Beneteau because of the distance from the engine panel to the starter on then engine. I don't think your starter switch is bad. You may have to install a small relay.
2. problem with No RPM showing. Yanmar engines connect the tachometer lead to the fly wheel housing not the alternator.

I solved the problem. Had made a stupid mistake when wiring my relay.
Now just need to see if I can fix so the gauges are showing ok

[andreas.mehlin]

Originally Posted by WoodenKetch

Something is grounded that shouldn't be. Pegged gauges means short circuit. Careful or you will let the smoke out...

What I understand it's also the way they can act when the senders are broken? Especially if the lamp is still lit?

[hzcruiser]

Originally Posted by andreas.mehlin

I solved the problem. Had made a stupid mistake when wiring my relay.
Now just need to see if I can fix so the gauges are showing ok

Hmm, not sure if I sum it correctly: you jump on this forum after messing up the wiring of your engine, expecting some support, then you found some "stupid mistake" without telling us what the problem was in the first place, and then you're hoping the forum members to follow your trail and suggest how you can fix your gauges?

Do you see where I'm coming from ?