Just got back and about to start again. What would be a better way to wire it? There’s another option on his site that does away with the need for a prime switch but still uses the alternator, it does look a lot more complicated though.
Just wire it as per the pic I posted. The diagram you posted before can't possibly work (or do what you want it to). Your engine will stop once the carbs run dry.
Thanks, I’ll have a go at that. It did work before, maybe another ‘fault’ was causing the pump to run when it shouldn’t have!
Another poss is to fit an ignition-triggered fuel pump relay, the subject of much recent discussion on here. Then you don't need the alternator connection at all.
Its really easy and works well, momentarily priming the carbs on turn of the key without any faffy switches etc. I just wired mine like this. Connect wires as per Ratwell and job done: https://www.ratwell.com/mirror/www.dolphinsci.com/relay.html
Did you get a new relay or go the scrapper route? I don’t fancy spending a load of extra money when the setup I’ve got works (sort of anyway) and I’m redoing it to Snotty’s diagram. It’s more ‘modern stuff I don’t / barely understand’ to go wrong as well!
New one. It was about £30 quid I think. It was sold as a "MK1/2 SCIROCCO Fuel Pump Relay, With Fuse" - 321906059C
Someone on here is using the reverse lights to trigger a relay to prime the pump. I like that, it sort of goes with pump up washers and the engine being in the wrong end. If this is you, did you double up on the alt triggered relay or fit one just for this? Ta.
That’s a good idea and no one would ever think to put it in reverse to make it start. The only issue for me is I can never find reverse, it usually takes 5-6 goes of creeping forward before it clunks in!
I’ve printed the diagram off and writing the colours it on as I attach them. I used to have numbers and letters that slipped over cables but chucked them during a house move. Typical!
https://www.cablecraft.co.uk/cable-identification/swa-and-outer-core-marking I used this company when I worked in certain industries where the specification detailed that cables and cores be identified the link is an example that fits over cable marker but can easily be fitted over a conductor
That’s how it’s supposed to work. The relay is only energised when the ignition is on but the engine is off with no 12v from the blue wire to the charge light. As soon as the alternator starts charging the relay drops out.
Ignition on, engine off pulls the relay in and disconnects the pump, once the engine starts and the alternator is charging the relay drops out reconnecting the pump. But if the charge light doesn’t come on with the ignition the relay wont work and the pump will run constantly.
It’s all getting very complicated but I think I understand what you’re saying. Which of the two ‘Jim’ diagrams is the better/safer way?
Yes, you’re right. Noticed later that one side of the coil is connected to +12, not ground. If the alt light output is behaving, it will work. But the ignition-triggered job is a better solution.