Engine trouble!

[IC7]

Hi all, we’ve recently installed 4 new leisure batteries on our narrow boat. All connections are fine and all batteries, including starter battery, are reading over 12v with a multimeter, as well as on our panel in the boat. After putting isolators back on engine started fine. We let it run for 10 mins then turned it off. When we went to start her again, the engine turned over and sounded like it was trying to start but then gave up. The battery light circled in the picture attached stayed on. Diesel level is fine and we haven’t touched anything else. Any ideas greatly appreciated ?

[Jen-in-Wellies]

Would the battery isolators happen to be ones with red keys by any chance? Try cycling the engine isolator off and on a few times. The contact it is making may be poor and not flowing enough current to spin the starter properly. Try looking for poor contacts generally. Corrosion on nuts and studs that the wires are attached to. You can read 12V+, but a poor contact somewhere will restrict the flow to the starter.

Jen

Edited September 24, 2020 by Jen-in-Wellies

[Mike Adams]

Check the Isolators first and all other connections you have messed with.  Most isolators are crap and often fail after you disturb them Probably just a bad connection. Measure the voltage at the stater motor when trying to start the engine. If it falls very low (<6v) you have a problem. Just work back to the batties at every point measuring the voltage when trying the starter.

[Jen-in-Wellies]

Good advice from @Mike Adams. Take care when working around the engine taking voltage measurements while trying to start it. Keep away from drive belts and so on.

Jen

[IC7]

Thanks everyone, will give all that a try and report back!

[Alan de Enfield]

4 hours ago, IC7 said:

Thanks everyone, will give all that a try and report back!

Just remember that at 12v the batteries are quite discharged (about 60% discharged).

 

Fully charged 12v batteries should read 12.7v - 12.8 volts after they have been stood for a couple of hours with no input and no output.

 

If you have the batteries 'on charge' the reading can be anything up to 14.6 volts.

 

 

12v is almost 'flat'.

 

 

 

[matty40s]

Worked on a boat last week that phoned up and said they needed new batteries as they were very flat after every journey. 

(Purchased 3 years ago from Whilton, new batteries and starter motor installed, boat on a landline 50 weeks a year and used for occasional weekends out only).

Tested batteries, 9v(after an hours cruise)

Tested alternator, zilch, absolutely knackered.

Removed it and took it to a test centre, replaced. 

Stuck landline on whilst away, batteries recovered to 12.5 by the time I got back.

Installed it, with a fresh belt and straight away was reading 19v +.....somethings not right here....batteries still reading 12.5v

Head down the battery back under the back steps, all connected well, no loose terminals, checked bus bar....something missing....

Found the live feed cable under the battery bank, unconnected to anything, and hasnt been for 3 years. 

[Tracy D'arth]

A virtual charging lead? And who fitted the batteries? I'm amazed that you never found this for 3 years.

[Tony Brooks]

6 minutes ago, Tracy D'arth said:

A virtual charging lead? And who fitted the batteries? I'm amazed that you never found this for 3 years.

I took his post to mean he was on that boat as a job, not owning it or doing jobs on it for three years. The owner is very lucky alternators self limit current wise otherwise the wiring harness may have caught fire.

[Sir Nibble]

Something I'm not clear about. That battery light, it should be on with ignition on and engine not running. When you say it stayed on, do you mean after the failed start attempt (which is normal) with the engine running, or with ignition off?

[matty40s]

33 minutes ago, Tracy D'arth said:

A virtual charging lead? And who fitted the batteries? I'm amazed that you never found this for 3 years.

The yard/broker was mentioned at the top, first time it's been to us so we would have struggled to find it for the preceding period.

[Tracy D'arth]

47 minutes ago, matty40s said:

The yard/broker was mentioned at the top, first time it's been to us so we would have struggled to find it for the preceding period.

Glad it wasn't you how fitted them!