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MG Midget and Sprite Technical - firing 3 only

hi all
got a problem with 1275 engine only fires on 3 good compretion and spark any ideas regards robbie
RP Devine

Have you got a spark to all four HT leads?

Have you checked each plug?
Dave O'Neill2

First question

How do you know it is firing only on 3 pots?
Robert (Bob) Midget Turbo

yes done all the obv checks
RP Devine

can hear it bob
RP Devine

So for all you know then it could be simply firing on 2 cylinders? would that be right?
Robert (Bob) Midget Turbo

this has been 20 year rebuild now getting near the end just this prob with no2 cly
RP Devine

this is my first [post do i have to keep going back to thread to repl ?
RP Devine

The reason why I ask is that I rather fancy this could be a fueling problem affecting both 1 and 2. When this is the case very often people remove the plug caps one by one and generally will see no difference when the 2 is removed but will be a weak mixture on the front carb.
Robert (Bob) Midget Turbo

yes bob i catch your drift i to think carb prob how would i check
RP Devine

First remove filters and see if both pistons rise in the carbs when the engine is revved. These should rise at the same rate, if not fill both with fresh oil. Also chech that both float bowls are full of fuel then check mixtures as normal by raising each piston slightly. Oh and make sure both are balanced correctly
Robert (Bob) Midget Turbo

I am going in my garage now to do a bit of work so good luck and see you later.
Robert (Bob) Midget Turbo

thanks bob will try that and let you know
regards robbie
RP Devine

took bobs advice
front fuel bowl empty all ok now
many thanks to bob and the rest of you guys
RP Devine

Can you tell us why it was empty and what you did to fix the problem?
Dave O'Neill2

yes car has been having restoration over last 20 years
last time the engine was started was about 4 years ago
the float valve was stuck so stripped down and cleaned some times you cant see the wood for the trees big thanks to bob landed on it straight away
RP Devine

This thread was discussed between 30/12/2011 and 31/12/2011

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