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MG MG Y Type - Poor idle / fuel issue

Occasionally when I start my YB, the engine surges at idle up and down as if I were revving the engine a few hundred RPMs. If I drive the car, it sputters a bit and seems low on power. Normally the car is fine. The times I remember the car doing this it has been warm out. Any ideas what could be causing this? I did sense the smell of fuel when it happened last so I was assuming it was flooding.

Not sure if it's related but sometimes when I start the car regardless of whether the engine is warm or cold, a large puff of exhaust comes out with no other symptoms.
Steve Simmons

Is the carburation OK - take all the spark plugs out, check them for colour, clean them, check the gap and adjust as necessary.

Could be a worn carb jet, or just junk that has got into the system / rust that has come through.

Carefully dismantle the filters out of the pump and clean them, take the carb assembly off,strip, clean and reassemble.

Best of luck

Paul

Paul Barrow

The odd thing is that it only does it occasionally. Seems it usually happens when I've recently stopped the car. I'll give it all a check at the next opportunity. The car otherwise runs perfectly, and more often than not idles equally as well.
Steve Simmons

Steve - With the climate you have down there, you may be getting a vapor lock. I suffered that on our TD after restoring it and finally installed a heat shield betweent he carbs and the exhaust manifold. The vapor lock builds in the passage betweent he float bowl and the jets in the carb, in my case on the front carb. I have a write up, picture and template for the heat shield if you are interested in such. Before going to all that trouble, you might want to check a few other things first. Check the grill slats are not bent too flat to the point that they are cutting off air flow. Also check that the engine is not running too lean and thea the timing is correct. incorrect timing or a lean running engine will cause it to run hot and then a vapor lock can form on shut down when all the heat is trapped under the hood. Good luck- Dave
David DuBois

It sounds like fuel evaporation but it may be the butterfly in the carb play where it revolves in the carburettor body.
John

Thought that too especially with unleaded petrol.

Excellent data sheet on Fitting a Heat Shield available from Regalia Sales.

Solved many of my problems.

Paul
Paul Barrow

You can also reroute the petrol-line, instead of over the hot manifold my line was modified by the PO with a longer rubber hose to run over the radiator-stay. I'll mail you a picture.
Willem van der Veer

I was wondering what that picture you sent was for! Thanks. :)
Steve Simmons

This thread was discussed between 10/05/2004 and 12/05/2004

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