Sticking starter solenoid - I think.

J

jsl

Well-Known Member
Joined
19 Dec 2001
Messages
287
Location
BA2
Visit site
Would I be right in my guess? Symptoms: 10 amp discharge when I turn the key to start, but no turning of the engine. I have re-made all the connections at the batteries without result. I have banged the back end of the starter-motor with a spanner and got normal starting. This has happened twice now, with several normal starts before and after each refusal. Intermittent faults are always scary: advice, please, on what I should do next.
 
I agree that the symptoms suggest a sticky solenoid. Presumably your starter is of the pre-engaged type.
I suggest that the starter motor is removed and checked over.
The cause of the sticking might be visible. Replacement the solenoid should be possible, but is not a simple job.
 
I agree with earlybird. The symptoms suggest a sticking solenoid...... maybe little rust somewhere.

clean and check the mechanism for easy free operation.

While you are there check the solenoid contacts.

Also worth checking the starter motor brushes and commutator.

A local auto electrician should be able to fully recondition the starter for a fraction ofthe cost of a new one if you do not feel able to fix it yourself.
 
Very helpful if rather grim news: thank you both. It will take a contortionist to get the starter off the engine, I fear. Is there any way of getting lubrication into it without dismantling? (I suspect I know the answer: you would have mentioned if it were possible.)
 
Assuming it is a pre-engaged starter (the solenoid is mounted on the starter) .............

There is no "bendix" (post #5). The bit with teeth that whizzes around is called a pinion. This should not be oiled or greased.

There is a piston in the solenoid that operates a lever, which engages the pinion with the ring gear on the flywheel, before the motor starts to turn (hence pre-engaged). When the piston reaches the end of it's travel it basically shorts two contacts together to engage the motor.

The symptoms in post #1 are caused by one of two things, or both. The piston sticks, therefore not reaching the end of it's travel and completing the circuit, or the contacts are dirty and the circuit is not completed. It's possible to take the solenoid apart and clean it, along with the contacts, and spray some PTFE on the piston (SailKote will do the trick).

However, if it is a real pain to get to, i think i'd be inclined to take it to an automotive starter repair guy and have a new solenoid fitted.
 
jsl said:
Would I be right in my guess? Symptoms: 10 amp discharge when I turn the key to start, but no turning of the engine. I have re-made all the connections at the batteries without result. I have banged the back end of the starter-motor with a spanner and got normal starting. This has happened twice now, with several normal starts before and after each refusal. Intermittent faults are always scary: advice, please, on what I should do next.
Click to expand...

FWIW : from a few weeks ago :

Re: Starter motor replacement - Volvo MD 2002 18hp.

Finally I have ordered a starter from MANCHESTER AUTO ELECTRICAL LTD for a total delivered price in France of £75.

It will probably p!$$ off the French mechanic. See OP.

Read more at http://www.ybw.com/forums/showthrea...cement-Volvo-MD-2002-18hp#uiJAiOhu1bOcBpv3.99

Originally Posted by Sybarite
image: http://www.ybw.com/forums/images/ybw/buttons/viewpost-right.png

Starter motor received in France at 9:30 this morning. Good service, good price.
Epilogue.

I fitted the new starter motor (net cost delivered to me = €87.04) but it still did not start. There was a clicking sound at the relay and so changed that (€17). Even then it did not start. Found that there was little fuse box (on top of the relay) and plugged the lead into an adjacent plug. And it worked. The problem was one tiny fuse worth pennies.

When I was with the Volvo concessionnaire I checked the price of their standard starter motor. €1400...!!! (a bit more than €87...!!)

However the shaft appears to running rough and so I will probably have to change the shaft, stuffing box, and cutlass bearing.

At least I have repainted the stripes on the boat and it's looking super.

Read more at http://www.ybw.com/forums/showthrea...cement-Volvo-MD-2002-18hp#uiJAiOhu1bOcBpv3.99
 
Worn brushes or corroded brush holders can give these symptoms, the jolt of the tap is usually sufficient to persuade the brushes to briefly make contact with the com. You will have 2 large ( M8) terminals on the solenoid, one connected to the battery by a large cable, the other terminal disappears into the start motor. Connect a volt meter on the terminal with thd lzrge wire first and invoke the start button battery volts should be present if the start motor does not actuate 10+ volts if the engine cranks. Assuming volts are present, connect meter to other large terminal and invoke start switch, 10 to 12 volts will be indicative of a healthy solenoid but motor malfunction.
 
Thanks everyone: more useful advice. It is good to have agreement about the likely cause of the non-starting. If I thought I could take the solenoid off myself, I'd do it. Then it would be easy for me or the factor to deal with. But I just don't fancy the contortions, so I think I'll have to pay.
 
PaulRainbow said:
If you oil the piston it sticks.

If you oil or grease the pinion and ring gear it either comes off rapidly, making a mess or it attracts dirt and causes wear.
Click to expand...

They were the reasons for not oiling or greasing a bendix gear when installed in vehicle clutch housings.

Below are the lubrication instructions for a pre-engage starter motor and solenoid

DSCF1683.jpg
 
VicS said:
They were the reasons for not oiling or greasing a bendix gear when installed in vehicle clutch housings.

Below are the lubrication instructions for a pre-engage starter motor and solenoid
Click to expand...

I agree with Vic. I mentioned lightly oiling the solenoid and pinion on a car starter a few months ago and attracted the same criticism. As I said on that occasion, the original starter motor had started sticking so what's the worst that lightly oiling it could do ...... cause it to stick? ;)

Richard
 
VicS said:
They were the reasons for not oiling or greasing a bendix gear when installed in vehicle clutch housings.

Below are the lubrication instructions for a pre-engage starter motor and solenoid

DSCF1683.jpg
Click to expand...

If you thought you knew the answer, why ask the question ? Oh yes, being your usual smart arse Googling self.

The same reasoning applies now as with bendix type starter motors. The shaft is lubricated but the gear isn't. As Peter stated, graphite powder is the traditional choice for the solenoid piston, lately PTFE is more commonly used. Grease is a shit idea.
 
RichardS said:
I agree with Vic. I mentioned lightly oiling the solenoid and pinion on a car starter a few months ago and attracted the same criticism. As I said on that occasion, the original starter motor had started sticking so what's the worst that lightly oiling it could do ...... cause it to stick? ;)

Richard
Click to expand...


Cause it to stick worse. Create a grinding paste in the pinion and ring gear teeth and cause premature wear.
 
You must log in or register to reply here.

Share this page

Top