yet another "engine cutting out" thread.

[Moggie94]

When I rev the engine, instead of it coming back down to normal idle speed, it starts struggling, and goes right down below idle and starts struggling... half the time it just about recovers after a few seconds and goes back to idling smoothly again.

Been trying to eliminate variables so far I've got:
the carb piston goes all the way up and falls with a clunk,
the plugs are beige,(and new)
the timing is just backed off from pinking in 4th uphill,
Sealed up an exhaust manifold leak, no difference (or when the leak came back)
Throttle has no play in it, and comes back to rest on idle speed screw.
Topped oil up in dashpot

I'm stumped, problem is very much still there and is getting annoying, any ideas?

[bmcecosse]

No - you've covered it all! Can only suggest general ignition overhaul - points/condenser/rotor arm/cap/HT leads - not necessarily renewing everything - but cleaning and checking. Also worth checking the throttle cable - is it sticky??

[David W.]

I had similar symptoms, and found that the points gap was nearly nil, and I had forgotten to tighten the distributor.

[Moggie94]

Head gasket blew today, whether it was the cause or an effect I don't know

[bmcecosse]

Probably the cause of it all... Good chance to grind in the valves !

[Moggie94]

Found the cause of the cutting out, exhaust is blocked somehow.
I can barely even blow down it, no wonder the engine couldn't breath properly and kept popping the pipe off at the manifold.


While it's in bits now's the time to upgrade the engine with the bits I've accumulated methinks.

[bmcecosse]

Blocked exhaust! That's a new one on me ! Well done finding it. If you take it off - you can set it on fire to clear out carbon/oily mess.

[katy]

I've seen blocked exhausts from cars being backed into a snowbank, which causes a bunch of snow to get stuffed up the tail pipe,the snow partially melts from the warm pipe and then subsequently freezes into a block of ice.
Other times people have stuffed a raw potato up the tail pipe of a friends car that has been parked. The potato freezes and blocks the exhaust.
I don't know if you get cold enough winters in the UK for these scenarios to happen over there.

[bmcecosse]

Not as cold as Red Deer.......