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 Post subject: difficult starting
PostPosted: Sun Jul 08, 2018 3:07 pm 
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My 101 has always been difficult to start and I've been told that's because the oil pressure needs to build up first - a precaution against squaddies revving the engine too soon after starting and damaging it. Does anyone know how to disable this feature? Does the oil pressure switch cut the power to the coil until it's reached working pressure? Is there a wiring diagram which explains this?


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 Post subject: Re: difficult starting
PostPosted: Mon Jul 09, 2018 7:45 am 
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My understanding of how this works is that start up is not affected, it only operates once engine is running and will cut engine if pressure drops. Poor starting is probably something else eg carbs.

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 Post subject: Re: difficult starting
PostPosted: Mon Jul 09, 2018 8:22 am 
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Thank you. I will investigate the carbs


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 Post subject: Re: difficult starting
PostPosted: Mon Jul 09, 2018 8:25 pm 
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Mine is the same, oil pressure needs to build up to run the fuel pump. Heard it said the pump runs when cranking, but not sure if this is the case or not. I crank until green light goes out, stop cranking and fuel pump runs. When oil pressure light comes on I crank a bit more until oil pressure light goes out. When I think fuel up to carbs crank and it fires!

Has to be said I've had it a while so I'm used to it, also have a big battery on it so a bit of extra cranking doesn't bother me. Obviously if it's been stood a while all the fuel has run back down the pipes so takes a bit longer.

A solution would be to have a push button to run the fuel pump to prime the carbs, never got round to it on mine.

Think it's a feature to protect in case of an accident, engine stops, ignition still on and you don't want the pump to run and pump fuel all over the place...

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 Post subject: Re: difficult starting
PostPosted: Wed Jul 11, 2018 10:48 am 
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The pump should operate during cranking via the brown/red feed to the oil switch.
The oil switch is there to prevent engine damage should oil pressure drop below minimum whilst the engine is running by cutting the feed to the fuel pump.
There is a wiring diagram in the workshop manual in the engine section which describes the operation.

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 Post subject: Re: difficult starting
PostPosted: Fri Jul 13, 2018 6:25 am 
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ptsteer wrote:
The pump should operate during cranking via the brown/red feed to the oil switch.
The oil switch is there to prevent engine damage should oil pressure drop below minimum whilst the engine is running by cutting the feed to the fuel pump.
There is a wiring diagram in the workshop manual in the engine section which describes the operation.


As Pete says when cranking the oil pressure switch is fed by a Brown/Red wire. The other end of this wire is from the starter Motor's solenoid, and then traces back from there to the remote starter relay. When the starter relay is energised by the ignition/starter switch power is fed to the operatong coil of the starter relay, this switches power to the Starter Motor's solenoid (also Brown /Red wire) and the power is carried to the pressure switch for as long as the starter relay is energised.

On my 101" the starter relay had been bypassed and power from the Ign/Starter switch was being fed directly to the starter's solenoid when the key was turned to start. I have since re-inststed the Starter relay into the circuit.

The starter relay is hidden away on top of the right Hand front wheel arch, behind the wheel and under the RH seat. .....

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 Post subject: Re: difficult starting
PostPosted: Wed Jul 18, 2018 1:29 pm 
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I’m not sure this is of any use that you but both my series 2 and the 101 run the cut off for the fuel pump to the oil pressure switch. When it’s been stood for a while I need to crank over either till the pressure light goes out the. Wait while the pump has a chance to fill the lines etc before it cuts again. I’ll do that again and usually both will start after that.
They both need a little more turning over when hot.
Hope that’s of any use.

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