Port engine will only start using the LINK switch

[Thepipdoc]

My Sealine F33 (KAD32's) port engine will only start if I use the battery link switch.
In fact I get no response what so ever from the port ignition untill I flick the link switch. Once I press the link switch the warning lights become illuminated and I can start the port engine. When it fires up, I then release the link switch and the rev counter and warning lights are all dead. The rev counter, oil pressure, temp gauges etc. will only become active if I hold the link switch for a split second.
I know the port engine battery is healthy - I've had a drop test carried out.
I've checked the battery connections and anything obvious but I've had no joy.

It doesn't matter if I try to start the engine from the flybridge or the lower helm - the port ignition remains dead
Any suggestions would be greatly appreciated.

 

[volvopaul]

So your linking your 2 domestic/stbengine batteries to start the port engine, once its running as a marine diesel thats has voltage activated stop solenoid will run for ever as long as it has fuel and air, but id say although you have drop tested presume with a hydrometer, has it actually got voltage above 12v and have you load tested it or placed a multimeter at the terminals then cranked the engine.

It looks like the battery to me as you loose your gauges when you release the stb battery, but baffles me as once its running the alternator should take over to supply current charge back to the port battery, unless its that flat it wont excite the alternator, or has the bad battery caused the alternator to fail.

Firstly I would fit a battery from the stb engine into the bat box etc of the port engine that way you know the battery is A1 and charged, if it wont start it then you need to be looking at the H tension cables from the port battery up to isolator switch then to the starter motor.

Id also check the isolator as ive replaced many on f33s that have burnt out, thinking about it id probably go for that first.

Also if the batt switch has failed dont run the engine as the alternator when the link switch is released wont run a circuit back to the battery thus blowing the alternator.

 

[pappaecho]

Clearly you have no connection to the port battery. Has it got a master in line fuse?
The fact that the ignition light is not even lighting when connected to the port battery, means there is no connection from the battery to the engine.
I am assuming that you have some sort of changeover switch. I think that you need a meter, so see if you have any voltage from the port battery to the switch. It may be that the switch itself is at fault.
The other possible fault is the negative side. Using a meter you would need to check if you have a connection from the port battery +ve via the meter to the starboard -ve, and vice versa.
You have a major disconnection - usually if it is a bad connection you will get lights, but not enough power to crank the system.
If you have a very good quality jump lead, you might try a direct connection from the battery terminal straight to the starter motor terminal. If the system cranks momentarily, then it the circuit from battery terminal via the changeover switch to the starter solenoid. I I have no idea of how old the engines are, but older engines tended to take their power takeoff for the engine loom from the spade connector which was linked to the battery +ve cable ( heavy duty) If the spade connector has jumped off, then there will be no power on the complete loom. Check that all spade connectors are properly seated on the starter solenoid. If in doubt compare and contrast with the connections on the equivalent starboard engine solenoid

 

[Cheekybrat]

Id also check the isolator as ive replaced many on f33s that have burnt out, thinking about it id probably go for that first. quoted from volvopaul.

I would certainly check the isolator first as if you say the batteries are fine it seems a good bet the isolator is causing the problem
Nick Heath

 

[Thepipdoc]

Fantastic. Thanks for the detailed replies.
Im down to the Marina tomorrow so I'll be putting some, if not all of the suggestions to the test, will let you know how I got on.

 

[LukcyOne]

Exactly the same thing happened to us and it was indeed the battery isolator switch !!

Good luck !!

 

[DAKA]

Id also check the isolator as ive replaced many on f33s that have burnt out, thinking about it id probably go for that first. quoted from volvopaul.

I would certainly check the isolator first as if you say the batteries are fine it seems a good bet the isolator is causing the problem
Nick Heath

I had the exact same symptoms with my corniche that sounds wired the same way.

It was also the isolator switch, looked as new but was just about dead.

The contacts had become so badly soiled/burnt they would not allow any decent current through but did sometimes allow enough 12v through to light up a test meter which made tracing the fault a real pain.

just bypass the isolator and try it, 5 min job !

 

[Thepipdoc]

Well done all!
The problem was with the Isolator switch. It looked OK and the connections were good and tight, or so I thought, but a bit of a nip up with a spanner and hey presto, sorted!

Thanks all.

 

[rafiki_]

Good result, well done. Forum comes good again!!

 

[AllanJ]

Not to spoil the party, but to dip into the well of expertise;
I had a slightly different problem; the port engine started OK, but the link switch did not enable enough current to get the stbd started after the stbd batteries had apparently lost their charge. Usual clicking noise from the starter motor that you get when there is not enough juice. Eventually started after an hour on shore power to recharge the stbd batteries.
Question is why the link switch would not start the stbd engine even with the port one running?

 

[timbartlett]

Question is why the link switch would not start the stbd engine even with the port one running?

If one battery is "completely flat", then when you hit the link switch the first thing that happens is that current flows from the good battery to the duff one, so you have (in effect) two "partly flat" batteries.

The alternator on the engine that is running can't generate enough power to top up two flat batteries and start an engine all at once.

 

[AllanJ]

Thanks, Tim. Makes sense.