Volvo 2020 Starting Problem - Electrical

[widgeon]

When I last used my boat, in early December, she started fine on each occasion. Yesterday, I went to start the engine and there was no response, not even a click from the starter relay.

I checked the fuse in the starting circuit and it looks OK on the multimeter although I moved to a spare just in case. I get 12.8 volts at the engine start battery and also at the output terminal of the engine master switch on the cable leading to the starter motor.

However, when I test at the output of the starter circuit fuse, or at the back of the start switch in the cockpit, I get a voltage that fluctuates around 4.5 to 6.0 volts. Is this normal and, if not, is this likely to indicate where the problem lies. I don't get any sound when I operate the alarm test switch, but this has been intermittent for a couple of years and may just need another squirt of WD40.

Nothing in the wiring, or indeed anywhere else, has been changed or touched since she last started perfectly. I am baffled!

Nick

 

[VicS]

You should get the full battery volts at the fuse once the isolator switch is closed. That fuse supplies power to the instrument panel and the starter relay.

See the wiring diagram in the manual. Look at an older edition on the VP website if your manual does not include a wiring diagram http://www.volvopenta.com/volvopent...lication_search/pages/publication_search.aspx

Check all the connections.

It may be better to use a bulb on a pair if leads rather than a digital multimeter when checking for power supplies. ( or better perhaps put a bulb in parallel with the meter)

Digital meters take so little current they will often give a normal reading through a poor connection.

 

[widgeon]

VicS,

Thank you very much for your response and that link. I now know where to start digging for a bad connection.

Nick

 

[VicS]

VicS,

Thank you very much for your response and that link. I now know where to start digging for a bad connection.

Nick

Dont forget that you can have bad connections on the negative too !

 

[widgeon]

Good point, as a Land Rover owner that should be at the front of my mind!

 

[tillergirl]

On my 2030, I had a similar problem traced to a poor earth connection on the block. It looked fine, felt fine, was clean but it wasn't.

 

[widgeon]

Tiller Girl,

Thanks, I'll look closely there.