LCGB Forums

Quite often, when I turn off the ignition on my SIL GP150, the engine carries on running, I have to 'stall it' to stop the engine. Otherwise it runs well.
Any ideas please?

Hi Geotomc,
Probably ignition switch, or the earth wire(usually pink )from the ignition switch is loose or has a bad connection.When you turn off the ignition you short the green ignition wire to earth/ground via the ignition switch and pink ground wire. Check with a meter or open up headset and clean tighten up pink earth wire from ignition switch.
Grandpa.

If it is not that then you may have other more serious issues such as pre-ignition caused by overheating. Let's hope it's just electrical.

Also pre-ignition can have the same symptoms.This can be caused by a number of things including the top end needing to be de-coked.But as grandpa says,check that the wire on the igntion switch hasn't come lose.

Thanks guys, fingers crossed, I hope its the wiring.

Try with the right hand panel off & whip the plug cap off to see if it stalls.

That'll soon tell you quicker than anything else where the problem is likely to be...

BTW. Wear gloves when you try this

Warkton Tornado No.1 wrote:Try with the right hand panel off & whip the plug cap off to see if it stalls.

That'll soon tell you quicker than anything else where the problem is likely to be...

BTW. Wear gloves when you try this

Surely that will stall the engine regardless of any other problem?

Rich Oswald wrote:

Warkton Tornado No.1 wrote:Try with the right hand panel off & whip the plug cap off to see if it stalls.

That'll soon tell you quicker than anything else where the problem is likely to be...

BTW. Wear gloves when you try this

Surely that will stall the engine regardless of any other problem?

No, if it's really hot or coked up it will fire whether there's a spark or not. In the same way diesels work without a spark

Check the green wire hasn't fallen out or broken at the junction box - the one that goes into the loom towards the front of the bike.

I had an incident some years ago (won't be a minute love, just up to the garage get some petrol. ..famous last words!!) when engine wouldn't turn off. Had just fitted a secondhand engine without checking anything on it and had panels off. Switch wouldn't stop it; pulled plug cap off and sat in shocked amazement when it kept running. Pulled the lead out of the coil; why I don't know as plug cap was off and it screamed itself to what sounded like, destruction !! Screamed for what seemed like minutes.
I thought it had smelled a bit hot.
It turned itself into a diesel !!
2 hours later after pushing it home in a pair of flip flops (where the hell have you been xxx@@@!!!); the memory stays with me, still I can't believe what happened.

Post by EddieStone » Tue Sep 06, 2016 4:12 pm

Rich Oswald wrote:
Warkton Tornado No.1 wrote:
Try with the right hand panel off & whip the plug cap off to see if it stalls.

That'll soon tell you quicker than anything else where the problem is likely to be...

BTW. Wear gloves when you try this


Surely that will stall the engine regardless of any other problem?


No, if it's really hot or coked up it will fire whether there's a spark or not. In the same way diesels work without a spark

Check the green wire hasn't fallen out or broken at the junction box - the one that goes into the loom towards the front of the bike.

Thanks Eddie.

The 'plug cap' pull takes a brave man (with no gloves!) but is an easy, initial check to identify one way or another if it is pre-ignition or not.

Besides which, everybody should try it once in their life (without gloves) as I did on a mate's metal capped FSI-E thinking I was the Joker....

How many was it ..20,000 volts. To this day when people say "take the plug out and kick it over whilst holding it against the frame", I cringe in memory of the pain. It's something you definitely never forget !

EddieStone wrote:

Rich Oswald wrote:

Warkton Tornado No.1 wrote:Try with the right hand panel off & whip the plug cap off to see if it stalls.

That'll soon tell you quicker than anything else where the problem is likely to be...

BTW. Wear gloves when you try this

Surely that will stall the engine regardless of any other problem?

No, if it's really hot or coked up it will fire whether there's a spark or not. In the same way diesels work without a spark

Check the green wire hasn't fallen out or broken at the junction box - the one that goes into the loom towards the front of the bike.

Could understand that with the oils we used to use in the 70's but hard to imagine with modern oils which hardly leave any carcon build up at all. Never had to de coke in recent years like I used to do back then.
Green wire to the regulator is the most likely fault here.

Many thanks for your replies, I plucked up courage, and whipped the plug cap off (insulated pliers, dry cloth and gloves) can't be too careful, the engine stopped straight away. Wiring to check out now.
Once again, cheers.