What's up with my starter solenoid?

[Jed]

Isabella's been reluctant to start. Charged battery, key in, press start button, big click from the solenoid and nothing from the starter. Put the meter on the solenoid and get 12v in and 0v out when engaged. Take the solenoid out, pull the top off, lubricate the piston, check it on the bench, 12v in and 12v out when engaged, good. Put it back in the bike and click, no start, d'oh!. Check voltages, 12v in and 0v out again. Disconnect the starter motor get and 12v in and 12v out when solenoid engaged. Hmm, Touch the 12v solenoid input terminal with the 12v starter cable and away the starter motor goes and she starts first time. Why would the solenoid output 12v when the starter motor is not connected and 0v when it is?

Any advice gratefully accepted.

:-[

 

[Dellortoman]

G'day Jedzo

There's bugger-all resistance through the starter motor. It pulls a lot of amps and is pretty much equivalent to putting a dead short across the battery. So you'd expect a low voltage reading when the motor is energised, although I'd have expected something more than zero volts.

There could be crap or corrosion on the high current (secondary circuit) contacts in the solenoid that gives an OK reading under no load, but breaks down when under starting load. Similar to the way dirty batery terminals sometimes behave.

If you can get your hands on another starter relay (borrow the one out of your wife's car  ) wire it in and see what happens. If it works, it's confirmed that your starter relay is not performing. May be fixable if you can get it apart and clean the contacts.

Cheers
Cam

 

[Jed]

Thanks Cam, appreciate. I can get hold of a different solenoid so I'll wire it in and give it a go.

 

[Jotahowl]

        Have had similiar problems with my starter relay.  Basic'ly it was just worn out.  Easily
        replaced with a secondhand Suzuki unit,  quite cheap....no further problems. 

        Shorty NZ       


   

 

[Jed]

Hurrah, it was this old starter solenoid causing the trouble in the end. Something's not right inside. The electromagnet engages the plunger okay but enough current does not get through and the starter motor does not turn;

I figured I'd never find another Bosch 0333 006 004 solenoid like that so I thought I might put on one of these tre cool ones that I found instead;

It's got a KNOB.

Nah, I'd have to mount is somewhere exposed so I could push the knob. So then I settle on this new one from a V8 Ford;

It's not quite right fit wise with the terminals on the front and side not on the bottom and it'll have to have a bit of cunt and shutting to fit and not to foul the side panels but it works just fine.

All I need to do now is to sort out the two Dellorto's and the old girl should be ready for rego.

I'll take the old Bosch unit off to an auto electrician and see if it can be repaired. It'd be nice to think it could go back on. I don't think they were used for long on the 650's & 750's.