Bukh DV20 starter motor not working. Any suggestions?

[joyfull]

The starter motor on my DV20 has stopped working on a Westerly Centaur. First time since I have owned for two years and strangely a week after I had had a long 5 hour motor along the coast, my longest ever.

Red light ok on the panel. Stop solenoid clicks ok but no signs or any clicking noise when turned to start.

My first thought was battery as it was 12.5v (which had been ok up to now). Charged battery to 12.9v and still nothing.

Checked battery terminals, all good. Checked earth , all good, checked connections to starter motor and alternator all good. Lightly tapped start er motor with hammer. Still dead.

Any thoughts much appreciated.

Starter motor not too accessible.

 

[neil_s]

The multi-way connector mounted on the side of the engine, behind the starter motor springs to mind. The damp got into mine and some of the crimp connections broke up. I ended up doing a complete re-wire (without the connector), but try giving it a wiggle first so see if you just have a dirty connection.

 

[James_Calvert]

Will the engine turn over with the starting handle?

 

[Graham376]

Firstly, if you have a multi meter (or 12v bulb on wire) check if there's voltage with the key turned, to the start terminal on the solenoid. If there is, short out the two large battery connections on the solenoid (an old spanner works) and see if starter motor turns.

 

[srm]

If there is, short out the two large battery connections on the solenoid (an old spanner works) and see if starter motor turns.

I had to resort to this at times with a big Gardner diesel on an ex-fishing boat I owned. Expect lots of sparks and a melted blob on the spanner or screwdriver used.

 

[joyfull]

Will the engine turn over with the starting handle?

Sadly I don't have a starting handle! Wish I had.

 

[joyfull]

Access to the wiring of the starter motor and solenoid very very inaccessible. Just managed to get a picture. Not sure which two wires I should test for power or to short circuit with a spanner

 

[James_Calvert]

A starting handle would be easier, but if you decompress the engine, you may be able to turn it a bit by hand, pushing on the flywheel. The toothed rim can be a little sharp though so take care.

The object would be just to check the engine isn't resisting turning for some reason. You could also try the starter with the engine decompressed.

Forget all that if you've already established that the starter isn't engaging at all, ie no clunk when you turn the key.

 

[joyfull]

The starter is not engaging at all. Nothing when I turn the key. Though stop solenoid clicks when I turn key left. Flywheel turns very freely, does not seem to turn over the cylinders at all as they are not decompressed

 

[joyfull]

Picture from the front.

Is it fairly straightforward taking off the starter motor solenoid assembly (after removing the alternator). I guess I will be struggling with 40 year old nuts and bolts and studs again!

 

[joyfull]

 

[James_Calvert]

Access to the wiring of the starter motor and solenoid very very inaccessible. Just managed to get a picture. Not sure which two wires I should test for power or to short circuit with a spannerView attachment 98305

Just had a look at a spare starter motor to double check but of the three terminals you can see in this pic, the one with the blue wire is the one that should energise the solenoid for the starter motor. When you turn the key for starting, this should be at 12v. Can you put a meter or a bulb across this and an earth point on the engine, anywhere you can see bare metal, and check whether it registers or lights up.

 

[James_Calvert]

The large terminal with a nut on it to the right of that has a direct lead from the positive of your battery, probably the one with + on it.

The other large one is the positive that is directly connected to the starter itself.

When the solenoid is energised by the blue wire it makes the switch between these big terminals.

Be careful fiddling about, the only way of isolating that large positive lead from the battery is to disconnect the battery itself.

I'd be a bit wary of shorting out the two big terminals as suggested, not just the electrics but catching yourself or clothing on the engine if it turns over.

 

[James_Calvert]

View attachment 98311

Yes, it's mechanically straight forward. You need to undo the nuts behind the two bolts you can see in the picture. The assembly will then slide backwards out of its mounting.

You also need to disconnect all the wires going to the first two terminals I mentioned above. Best to disconnect the battery first.

Be warned, the assembly is probably a little heavier than you expect, significantly heavier than the alternator.

 

[joyfull]

Thank you James. All clear. Hoping those nuts and bolts are interested.

 

[James_Calvert]

Good.
But do check the blue wire first as suggested. It could easily be a disconnection in the loom or wiring leading to it, or in the ignition switch itself. And nothing wrong with the solenoid or starter motor.

 

[joyfull]

Yes. I will go through everything again and more before attempting the removal. I think more likely a bad connection problem. Difficulty is no side access hatch

 

[davidmh]

Make sure the starter pinion is free to slide in to the flywheel teeth, use a screwdriver to lever behind the pinion and it should slide easily into the teeth , you may need to move the flywheel a touch. This can happen after a long period of without use, a drop in oil on the spindle helps.

David MH

 

[Boater Sam]

Connect briefly a wire from the terminal on the solenoid with the blue wire to the heavy cable that goes to the battery. The solenoid should engage the gear and motor.

 

[joyfull]

Ok. Have to do with alligator clips as not accessible at all.