Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Engine cut out with faulty Inertia Switch

The engine would cut out unpredictably on the road at slow to high speeds. Very dangerous in heavy traffic.
I found that it could be restarted by first turning the ignition key off & then on using the starter or if I was quick leaving the car in gear with the clutch still engaged.
No cut out at idling revs.
Fortunately the local Morgan Service Agent, Cremorne Prestige Motors, found the problem to be a faulty inertia switch which was being activated by engine vibrations
They also relocated the switch away from the the oil tank on a vibration free pad.

Problem solved! What Next.

That's what makes the cars so endearing!

Seems quite odd that the inertia switch was resetting itself. They are designed to require a manual reset if they are tripped.

👍 my thought exactly.

This week I picked up my M3W at MMC after a rebuild with a new chassis (thanks MMC for this perfect service)

During this rebuild they also stripped the engine completely due to problems with the camshaft bearings.
Flushed the engine to get all metal particles out and installed new camshaft bearings.

When I picked up the car it was perfect weather so we went out for a ride in the Malvern Hills.
Wow, that felt great again !!
After 2 kilometers the engine stopped. Found out it was the inertia switch.
During our 70 kilometer ride we needed to stop 7 times to reset the inertia switch.

Before the enigen rebuild I never had problems with this switch during more as 30.000 kilometers.
So probably the rebuild engine gives now more of different vibrations which allow the switch to open.
Hope a new switch will solve this new problem.

Yes, correct it's the same generic switch used on all modern (ish) Morgans, your problem is more likely a poor connection into the actual switch from the plug below

For those of us who have never run across this issue, where is the Inertia switch located? I'm refering back to my official Three Wheeler Parts Book but don't see it anywhere.

Thanks

I experienced the same symptons, engine randomly cutting out, once just outside the M25 tunnel, and I too learnt that you could carry on by switching the ignition off and then on , without even stopping.
I eventually traced it to a poor pin connection in the 15 pin plug between the chassis loom and the engine loom, found by having the engine running and gently wiggling this plug in a certain direction, then you could hear the ignition relay trip out, so cuting the engine, then it would immediatley restart until another wiggle.
I couldnt imagine a cheaper looking 15 pin plug!

Mounted to the right hand rear of the oil tank - black rubber square looking thing.

Not sure it's possble in a M3W but I recently fitted an electric pump in mine and added an inertia switch for safety.I mounted it in the cockpit, just under the dash so I can reactive it on the move if it does trip over a bump or similar. I've also wired in a warning light, so I get a visual indicator if it's tripped.