Give it a bang to start....

[DeeGee]

Recently, my Beta 28 engine has developed a nasty fault. When I come to start, I do the warm-up bit, then twist the key - NOTHING!! This has happened at some very embarrassing moments, including being in a fairly stron current pulling me toward a load of moored boats and no wind.

However, the solution proposed by one or two boaters, was to give the starter a not-too-gentle-not-too-hard whack, to 'unstick' it. This works, but frightens the daylights out of me, cos I have no idea what is gooing on, and whether the solution will also fail at some point.

Any ideas?? Do starter motors have brushes? If they do, can they stick? Is it the solenoid stuck in some position?

I hear no 'click' or 'whirr' when I operate the key, just gentle silence. /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif

 

[minquiers]

clean all the teminals?

 

[elton]

It's a sign that something is going to fail, and you'll suddenly find that no amount of banging will get it to work.
It could be a corroded battery terminal, a dodgy solenoid, a faulty starter switch, a dirty or loose fuse, or many a thing.
Mine did the same over the summer. I discovered that a fuse had been replaced by a soldered-in wire (in a redundant though connected fuse holder), but the wire had a dry joint at one end; sometimes it would work, sometimes it wouldn't. Tapping and pulling at the wiring loom would get it to work, until one day it wouldn't. Luckily I was tied to my berth that day.

 

[Hugh Foulis]

This can happen if the starter bendix doesn't release from the flywheel ringgear. Starter motor off and clean everything, ensure the bendix is free to move up and down the shaft.

 

[cliff]

[ QUOTE ]
This can happen if the starter bendix doesn't release from the flywheel ringgear. Starter motor off and clean everything, ensure the bendix is free to move up and down the shaft.

[/ QUOTE ]AFAIAA the Beta 28 has a pre-engage starter (as do many diesels these days) not a bendix drive.
From the description I would suspect a dodgy solenoid - simple job to strip it down, clean and reassemble.
--------------------

"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>

 

[rogerthebodger]

When you "Turn the key" does the battery voltage drop (ant lights dim).

If so, starter stuck in starter ring.

If not, bad connection on battery/ starter motor/ solenoid / brushes

 

[elton]

I forgot to mention - yes starter motors have brushes. They are usually carbon rods, spring loaded to push against the commutator. Sometimes they stick, and a cleaning them will sort it out. Eventually, they do wear out and will need replacing (normally a fairly simple job). An auto-electrician would replace them for £20-£30 I'd have thought, but I'd do it myself.

 

[StanFolds]

I have had this fault on several of the old bangers that I used to run, still do come to think of it. The earth return for many pre-engage starter solenoids is via the starter motor brushes and the symptome described are a sign that they are wearing out. Cleaning and banging will only work for a short while, time to get them changed.
Stan

 

[Frankklose]

The problem is caused by the high current ( 10 Amps) of the starter solenoid. Add a relay to the starter circuit) and problem is solved. After some time of use, the contacts of the ignition lock are corroded and the voltage drop is too high. Therefore the solenoid doesn’t have enough power and a wack helps to move the shaft inside the solenoid.

 

[gandy]

Our starter motor was rebuilt by local auto electrical specialists. New solenoid, drive unit, brushes and a couple of bearings. Not quite the same symptoms, because ours would "click" but not do anything. Once it reached the stage of taking four or five attempts before starting it used to prey on my mind. Time to get it properly fixed.

 

[davidbfox]

In my experience with various vehicles starter motors can almost always be rebuilt by electrical engineers much cheaper than buying a replacement. Last one cost about £35 (Vauxhall Nova!).

 

[boatmike]

Would agree, but take it off, clean it, inspect and clean solenoid as cliff suggests but strip and clean commutator with fine wet and dry and fit new brushes if needed as well.

 

[pampas]

in ten years of testing and overhauling starters I have only seen two that had your symtoms that were cuased by the solenoid, as most people think. the rest, the main cause was one or more brushes worn or sticking, these can be done at home but you should first but some solder for aluminum or you will come unstuck /forums/images/graemlins/blush.gif

 

[William_H]

A starter motor must be engaged into the ring gear large gear wheel on the crankshaft to enable the stater to turn over the engine. However because of the high gear ratio the stater must be disengaged after stating to avoid the stater motor being driven by the engine at high speed, destroying the starter. (usually by a strong spring)
The pinion (small gear) of the stater is shoved ito the ring gear. One form of shoving this is to put the pinion on a helical spline so that when the stater motor starts to turn the inertia of the pinion causes it to lag behind the stater shaft which turns winding the pinion forward into the ring gear. This starter type is characterised by a harsh crashing engagement as the partially rotating pinion goes into the teeth of the ring gear. Electrically all you do is apply power to the stater motor to get engagement and starting. A remote solenoid relay will switch the high current from the battery via a small current through the stater switch.
OK the more common type of stater on diesels is the prengaged type. Here a electromagnet coil gets the power from the key switch. This pushes the pinion along a a spline into the ring gear. When the pinion has moved far enough the arm also operates big electric contacts which apply battery power to the stater motor. The solenoid is the lump mounted on top of the stater at the engine end.

Now if there is not enough elecric power to the solenoid the arm does not move enough to fully engage the pinion and the electric contacts are not made. So you get a loud click but no starter cranking.
You can bypass the start switch, main battery switch etc with a wire from the battery positive to the starter solenoid terminal. If you get good starting you have an electrical resistance in the wiring or the switches. As stated you may need to (fix the switch contacts or,fit a relay to give good current straight to the stater solenoid. Only a small current is needed through the start switch etc to operate this relay.
If this bypassing by wire does not fix the problem. Then probably the pinion is not sliding on the spline sufficiently freely due to corrosion or you may have a bad earth or possibly crook brushes on the starter. It is time to remove the starter. Usually 2 or 3 bolts and 2 wires. The starters are fairly easy to dismantle and you will see the spline and also the brushes. If they look grotty they probably should be cleaned. or heaven forbid you take it to a proffessional.
good luck ....olewill

 

[Frankklose]

Many small boat engines have no relay. The feed the 12 Volt via the lock to starter solenoide. After a while the contacts of the lock are melted and you hear only a click.
This is also what William explained.