Corroded solenoid connections

[doraymefa]

I would like to clean up these corroded connections on my starter motor solenoid. They are reluctant to undo. I don’t want to strip the plastic nuts. Is there a trick to undoing this sort of nut?
I have left them soaking in a good dose of WD40 in the meantime…

 

[snowbird30ds]

Just a pair of pliers should do it, once they move they'll probably be fine.

 

[wonkywinch]

WD40 isn't a penetrating oil, paint some diesel or Plus Gas or similar on there.

 

[MontyMariner]

Aren't the plastic caps push on?
I would have thought that you would need to get to the nuts under them to tighten them properly before the caps go on.

 

[doraymefa]

Monty mariner that makes sense.
I will now concentrate on pulling the plastic off rather than trying to turn them. If the nuts below are still stuck I will improve the penetrating oil. Thanks both you and WW

 

[Refueler]

I would like to clean up these corroded connections on my starter motor solenoid. They are reluctant to undo. I don’t want to strip the plastic nuts. Is there a trick to undoing this sort of nut?
I have left them soaking in a good dose of WD40 in the meantime…

Remove the plastics and then make sure all power is switched off at batterry isolators .. then good wire brush all that crap away .... then undo the nuts ... carry on cleaning up ....

Why power isolated ? Ever seen what happens when a wire brush shorts terminals ???

 

[snowbird30ds]

Is that definitely the starter solenoid? Looks like a volvo oil pressure sender.

 

[PaulRainbow]

Is that definitely the starter solenoid? Looks like a volvo oil pressure sender.

I think you're right

@doraymefa can you post a pic of the whole thing ?

 

[Alex_Blackwood]

Aren't the plastic caps push on?
I would have thought that you would need to get to the nuts under them to tighten them properly before the caps go on.

I don't think they are push on. Look like standard terminals to me, the nut is embedded in the plastic outer

 

[VicS]

Is that definitely the starter solenoid? Looks like a volvo oil pressure sender.

I think you're right

Two grey wires would suggest its the tacho sensor if its a VP engine, but VP engines are not usually blue >>>>>. its a Nanni but I don't know the wiring colour code .

Unscrewing the terminals is the problem though , not the ID of the component
.

 

[PaulRainbow]

Two grey wires suggest its the tacho sensor if its a VP engine.

but VP engines are usually blue >>>>>. its a Nanni
.

VP engines are usually green (typo i suspect?)

Could be Nanni, but looks quite old, might also be a BMC or Thorneycroft.

Engine make isn't really importand, it's likely a VDO sender from any of the above.

 

[VicS]

VP engines are usually green (typo i suspect?)

Could be Nanni, but looks quite old, might also be a BMC or Thorneycroft.

Engine make isn't really importand, it's likely a VDO sender from any of the above.

Yes typo , but already corrected

In another recent thread the OP refers to a Nanni 2.14.
.

 

[wonkywinch]

I would like to clean up these corroded connections on my starter motor solenoid. They are reluctant to undo. I don’t want to strip the plastic nuts. Is there a trick to undoing this sort of nut?
I have left them soaking in a good dose of WD40 in the meantime…

If the connections are good, then there is no need to disturb everything. Just spray some rust remover then rinse/brush off and repeat as necessary.

I use Bilt Hamber Deox and Korrosol products. Then spray with XCP rust blocker.

Anti-Corrosion – Bilt Hamber

Rust Blocker - XCP® PROTECTION

 

[Graham_Wright]

If it is the starter solenoid, disconnect the supply at the battery. A few staggers with the spanners could result in some interesting consequences!

 

[Sandro]

WD40 isn't a penetrating oil, paint some diesel or Plus Gas or similar on there.

Is it not? I always used it and it seems working.
Let's clear the matter, may be someone else can help.

Diesel is surely good and CRC 6-66 also.

 

[penberth3]

Is it not? I always used it and it seems working.
Let's clear the matter, may be someone else can help.

Diesel is surely good and CRC 6-66 also.

Let me agree with you. WD40 is a general purpose product. It works very well as a penetrating oil. A dedicated penetrating oil might work better, it might not.

I don't think diesel is any better, and it makes everything stink.

 

[penberth3]

If the connections are good, then there is no need to disturb everything.....

They'll have to be removed one day, so why not crack on and deal with it now? The OP is obviously in the mood to get it sorted. I hope he hasn't destroyed the plastic bits yet, as some suggested.

 

[Refueler]

Let me agree with you. WD40 is a general purpose product. It works very well as a penetrating oil. A dedicated penetrating oil might work better, it might not.

I don't think diesel is any better, and it makes everything stink.

And WD40 does not stink ??

Anyway WD40 is crap and only good for spraying into padlocks !! There are far better products out there ...

 

[doraymefa]

They'll have to be removed one day, so why not crack on and deal with it now? The OP is obviously in the mood to get it sorted. I hope he hasn't destroyed the plastic bits yet, as some suggested.

 

[doraymefa]

I can assure you this is the solenoid attached to the starter motor on a Nanni 4.50.
Thanks for the warning re disconnecting at the battery - I had already clocked that but very good to be reminded.
The engine is not old, but this connection is hidden and I noticed the corrosion when working on something else. It just happens to be in line to be dripped on when I change the pencil anode on the exhaust.
I have committed the sin of asking AI about the ‘knurled terminal nut’ in this set up and it suggests that the plastic is only a cap and underneath I will find an honest nut.
This has been a great reminder to me about the importance of pottering about the boat with open eyes and how good this community is when helping, thanks everyone