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MG Midget and Sprite Technical - Midget dies when she gets hot!

Hi

I have a midget 1500 which has just come back on the road after 5 years in under a sheet!

She got through her MOT okay but when the engine gets hot. after about 10 miles or so, she gives off a petrol smell, falters and dies, as if she has run out of fuel. Leave her to cool down and she is fine again. I am not sure if the fuel is evaporating in the pipe, but she never did this before? I am going to change the HT leads, distributor cap and rotor arm, mainly because I know how to do that! It may help though?

My knowledge, and technical ability, is limited so I can't work out what is wrong. the car is older that most of the mechanics at my local garage and they keep looking for somewhere to plug their diagnostic machine into. (not impressed with them)

Does anyone have any ideas what I should do?

Thanks

Mack
g mcpartland

Hi Mack

I had a similar problem with my MKII last year. It turmed out to be the coil was old and getting too hot causing it to fail temporarily ontil it had cooled dowm. The smell of fuel may well be from the attempts to restart it when it doesn't want to!

HTH

Tony
A Brough

blooming heck, that was quick Tony!!

I might as well get the coil as I am getting the rest of the ignition stuff.

Thanks

Mack
g mcpartland

Have a look on the thread about hot running 1500s in the general too ... :)

Mine is coz the carbs desparately need resetting and time never works on my side!
rachmacb

Sounds like it could be fuel vaporisation, for that matter. Are your carbs fitted with a heat shield?

On a related note, are you sure that your carbs' float valves are sealing correctly? The petrol smell you mentioned can be caused by a float chamber flooding and venting, and this can certainly cause your engine to stall as surely as fuel starvation. Been there...

Best of luck, and keep us posted,

-:G:-
Gryf Ketcherside

Well worth checking out the thread on the general page (hot running 1500) My experiance is that if the heat shield is missing or damaged the fuel in the float bowls starts to boil, this leads to the bowls sinking allowing extra fuel in which then leaks out of the overflow giving the petrol smell. Do you have the original engine driven fan? An electric fan will usually only cut in when the water gets too hot which may happen long after the heat from the manifold has boiled you fuel.

Carl
C Bintcliffe

just another thought to check for... bad fuel cap...when it dies try removing the cap and listen for a swosh sound and se if it will start back up.

theres a vent in the cap that allows air to breath in the tank... if its blocked its like sucking on a straw that blocked off. at the bottom.
Prop

>>> just another thought to check for... bad fuel cap... <<<

I'm not sure about the UK-spec 1500s, but the US models use a vapor recovery system and have a fuel cap that's sealed, not vented. That is, rather than venting fuel vapor to the atmosphere through the cap, vapor is drawn through pipes into the charcoal filter(s) in the engine bay and then pulled into the intake airflow for burning.

Note that if the vapor recovery system clogs for some reason - such as fuel overflow at the carb(s) filling the front charcoal bin with fuel - you can have issues. Ask me how I know...

Anyway, as suggested above there are several things to investigate here, both on the fuel and ignition side.

Best of luck - let us know how it goes.

-:G:-
Gryf Ketcherside

This thread was discussed between 23/05/2010 and 25/05/2010

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