MG Midget 1500 white smoke and misfire
MG Midget 1500 white smoke and misfire
Author
Discussion

auxilarygrub8

Original Poster:

33 posts

171 months

Friday 24th August 2012
quotequote all
Hello again,
I just finished stripping down my Carbs and refitting as my midget was chucking out plumes of white smoke that smelt like petrol and was very thick exhaust, it wasn't water as white smoke usually dictates. I have emptied my petrol tank and wiped out incase the fuel was contaminated , filled with new petrol and still no luck more white smoke . My other problem is its now started mis firing and i havn't touched the distributer ect . Any ideas anybody .

jagracer

8,248 posts

265 months

Friday 24th August 2012
quotequote all
Head gasket or maybe inlet valve stem seal or guide gone.

auxilarygrub8

Original Poster:

33 posts

171 months

Friday 24th August 2012
quotequote all
like i say the smoke doesnt smell right to be a head gasket and it lingers far to long .

SV8Predator

2,102 posts

194 months

Friday 24th August 2012
quotequote all
Head gasket is steam, not white smoke.

If it is genuinely white smoke and it stinks, it is brake fluid, usually from a leaking rear seal in the master cylinder letting fluid into the vacuum system and thus into the carb.

No brake servo on your car? Then it won't be that then.

auxilarygrub8

Original Poster:

33 posts

171 months

Friday 24th August 2012
quotequote all
yea its definatly not steam . or water vapor . so not head gasket

Globs

13,847 posts

260 months

Friday 24th August 2012
quotequote all
What do the plugs look like?

greeneggsnsam

648 posts

185 months

Friday 24th August 2012
quotequote all
Globs said:
What do the plugs look like?
I was about to say the same thing- could be the cause of the misfire and might give you more of a clue as to what the problem is.

Dogwatch

6,381 posts

251 months

Friday 24th August 2012
quotequote all
Diesel?

auxilarygrub8

Original Poster:

33 posts

171 months

Friday 24th August 2012
quotequote all
no brake servo on the car . so cant be that.
i havnt checked the pugs yet . ill do that tomorrow and update .
Just seems strange . i no the previous owner put 5 litres of diesel in it, realised this drained and replaced the fuel, when i got the car i drained cleaned duel pump flushed the lines cleaned the carb pots drained the tank. due to the smoke not going i have done this all again and ragged out the tank as best i can still no luck . could there still be something there though to cause smoke .

Globs

13,847 posts

260 months

Friday 24th August 2012
quotequote all
The 1500 has a fuel pump on the engine and a long fuel line - give it a run of a few miles to make sure you have got clean petrol through.

What you'll also find on that car is that the head gasket 'beds in' over time so you will need to re-torque all of the head bolts or you may get a leak - maybe an oil passage to the cylinder.

If they have never been done since the last gasket went on they could be surprisingly loose. Worth remembering if you end up having to change it.

Flying Phil

1,735 posts

174 months

Saturday 25th August 2012
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Another thing to check would be the crankcase breather system which is evacuated by the inlet manifold - it might be drawing oil?

auxilarygrub8

Original Poster:

33 posts

171 months

Monday 27th August 2012
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Just a quick update ive checked the plugs and they seem clean and in a good condition . The crankcase breather hose seems clean and not pulling oil . The white smoke seems to get worse as the engine gets hotter . The misfare has now stoped after I retuned the carbs however I cannot get the idle speed below 1150 choke off . All very cofusing . My next job is to check that the head is torqued down correctly after that its a call to the mobile classic car mechanic to see his views I think as im now outta ideas.

Globs

13,847 posts

260 months

Monday 27th August 2012
quotequote all
auxilarygrub8 said:
Just a quick update ive checked the plugs and they seem clean and in a good condition . The crankcase breather hose seems clean and not pulling oil . The white smoke seems to get worse as the engine gets hotter . The misfare has now stoped after I retuned the carbs however I cannot get the idle speed below 1150 choke off . All very cofusing . My next job is to check that the head is torqued down correctly after that its a call to the mobile classic car mechanic to see his views I think as im now outta ideas.
Yes check the head - the cam cover comes up very very easily (two nuts IIRC), mine were finger tight after a few weeks - your mileage may vary!

auxilarygrub8

Original Poster:

33 posts

171 months

Tuesday 28th August 2012
quotequote all
check head all torqued down correctly . found a cause of one of the oil leaks though the stud had a bald thred so two new studs and bolts orderd . however i think i need to get the mechanic in now for this white smoke gunna cost and bit of a downer