misfire

C

clivees

Well-Known Member

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2,070

Location

Somewhere in deepest darkest Hampshire

• Dec 20, 2007

• #21

I have never looked at it but there is a flap / vent on the inlet manifolds below the carb mount and just above the exhaust manifold.
This flap is controlled by a by-metallic spring and there is very little information on what it does or on how it works but i suspect that it's a carb heater for this very problem.
So you may want to check that you have one and its working before you start replumbing your landy.

 

C

CharlesY

Well-Known Member

Posts

7,084

Location

BANNED

• Dec 20, 2007

• #22

clivees said:

I have never looked at it but there is a flap / vent on the inlet manifolds below the carb mount and just above the exhaust manifold.
This flap is controlled by a by-metallic spring and there is very little information on what it does or on how it works but i suspect that it's a carb heater for this very problem.
So you may want to check that you have one and its working before you start replumbing your landy.

Click to expand...

That is the very doo-dah!
From cold, the flap opens only to the air over the exhaust manifold.
So, it takes air from over the exhaust manifold from a cold start, and that manifold gets hot in seconds as we know from burned knuckles. This stops the carb from freezing-up (icing inside) just after the cold start. As the engine warms up, the warmer air off the exhaust gets too hot for comfort or the good of the carb, and the bi-metal spring warms up and swings the flap over a tad to allow some COLD air to mix in. Thus WARMED air reaches the carb, but not too hot.

BL / BMC / Austin-Morris / etcetera were good at making these things work.
CharlesY

 

Davec

New Member

Posts

2,131

• Dec 22, 2007

• #23

From memory, the flap was dropped from later manifolds. On Land Rovers it only controls the air getting to the base of the inlet manifold, below the carburettor, so is physicaly warming up the maniforld and carb, unlike many of the car systems that actually diveretd the intake to the air filter, so altered the temperature of the air actually entering the carb.

 

jon123

Member

Posts

68

• Feb 2, 2008

• #24

this was an electical problem.
Changed dizzy complete with points condenser and cap and it all runs well now.

 

Davec

New Member

Posts

2,131

• Feb 3, 2008

• #25

Thanks for letting us know, I hope its a permanent solution.
I'm particularly pleased as I am having similar problems. I was already planning to change the dizzy, it's next weekends job, but was contemplating ordering a carb as well, but now I'll wait.

 

jon123

Member

Posts

68

• Feb 3, 2008

• #26

dave, yep the dizzy fixed this problem have been pondering it for weeks ran like s**t and broke down on every outing. i believe problem was the LT lead off the points and/or possibly the vacum advance, but a dizzy was about £17 so not worth messing about with. this time paddocks got it right and supplied the right bit.

 

Davec

New Member

Posts

2,131

• Mar 16, 2008

• #27

Dizzy changed some time ago, but had it's first good run, on & off road, today. Touch wood seems to have solved all the problems, some of which I was convinced were carb & fuel pump.
LZ scores again.