Volvo MD5 wiring problem

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All_at_Sea

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I'm sure someone can help. I have wired up a refurbished MD5 but find that after turning the key the engine turns over ok but on releasing the key the starter motor still turns. I've obviously wired something wrong! The engine came out from the boat so nothing has changed with the wiring other than l have a new starter and solenoid unit....

Any help? I need to sort this out before bleeding the engine and actually starting it!! Has anyone got one they could take a picture of so l can check mine?

Thanks in advance.
 
Not quite sure what to expect to gain from a photo!

There are wiring diagrams that should enable you to sort the problem out in the owners manual that can be downloaded from http://www.volvopenta.com/volvopent...lication_search/pages/publication_search.aspx


Main battery +ve lead to one large terminal on the solenoid together with the red lead from the alternator and the red lead that feeds the control panel
the other large terminal is connected to the starter motor

A white wire, from the key switch, goes to the small terminal
 
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All_at_Sea said:
but find that after turning the key the engine turns over ok but on releasing the key the starter motor still turns.
Click to expand...

When you release key, is this to the normal run position ? if so you may have a feed from the live switch terminal to starter motor.

If you have a relay between key switch and starter, you could be back feeding the coil latching the relay.

Brian
 
There is no relay according to the wiring diagram (q.v.)

If there was a live feed from the key switch then it would operate the starter as soon as it was turned on.

It is implied that the starter does nor crank until the key is turned to the cranking position but then continues to crank when released to the normal running position.

If that is correct it could be a faulty key switch
OR
there could be a connection between the switched terminal of the solenoid (the one that goes to the motor) and the coil connection ( the one with the white wire).
 
VicS said:
Main battery +ve lead to one large terminal on the solenoid together with the red lead from the alternator and the red lead that feeds the control panel
the other large terminal is connected to the starter motor

A white wire, from the key switch, goes to the small terminal
Click to expand...

On the back of my solenoid l have one large terminal for the postive lead, the red to the alternater and the red to the control panel via a fuse. There are two other spade terminals, one for the white, but which one and what is the other for?

I do not seem to have a cable to the starter itself, which is directly below the solenoid?
 
VicS said:
there could be a connection between the switched terminal of the solenoid (the one that goes to the motor) and the coil connection ( the one with the white wire).
Click to expand...

If it's a car solenoid, there may be a output on the solenoid to feed a ballast igntion coil when the solenoid is closed. Check for a feed to the pull in coil, crossed wires etc.

There may also be two coils in the solenoid, pull in and hold in, could be a fault in the hold in coil.

Run a temp wire to the start terminal on the solenoid, does it do the same, check wires on solenoid, if okay work back to switch.

Brian
 
I do not seem to have a cable to the starter itself, which is directly below the solenoid?
Click to expand...
Thats Ok there's a connection there somewhere but not one which is visible.

If one of the spades is labelled "50" thats the one for the white wire,
id not like to say what the other terminal is without checking it out

Disconnect the white wire connect a 12 volt bulb between it and earth

Now operate the key. The bulb should light when the key is turned to the "start" position and go out again as soon as the key is retuned to the running position

If it does that then the key switch is OK and the problem lies elsewhere.

Maybe the solenoid is simply sticking in the closed position!
 
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All_at_Sea said:
I'm sure someone can help. I have wired up a refurbished MD5 but find that after turning the key the engine turns over ok but on releasing the key the starter motor still turns. I've obviously wired something wrong! The engine came out from the boat so nothing has changed with the wiring other than l have a new starter and solenoid unit....

Any help? I need to sort this out before bleeding the engine and actually starting it!! Has anyone got one they could take a picture of so l can check mine?

Thanks in advance.
Click to expand...

Sounds like you have connected the small wire to the solenoid to the wrong terminal on the starter switch It needs to go on the terminal which is energised only when the key is turned to start.. You seem to have it on the terminal which is constantly powered when switched on. Possibly the next terminal in the direction the key turns is the one you want.
 
Bilgediver said:
Sounds like you have connected the small wire to the solenoid to the wrong terminal on the starter switch It needs to go on the terminal which is energised only when the key is turned to start.. You seem to have it on the terminal which is constantly powered when switched on. Possibly the next terminal in the direction the key turns is the one you want.
Click to expand...

If that had have been the cas ethe starter would have operated as soon as the key was tuned to run position.

The implication was that this did not happen, only cranking when advanced to the start position but continuing to crank when released back to the run position.

Anyway problem apparently now identified as a faulty switch
 
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