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MG MGB Technical - Rough Starting 78B

Sorry for the delay, called out of town..

Based on the original suggestions.. now in the archive under the same Thread Title:

Remove the air filter(s) and check for smooth operation of the pistons...when you reach in and lift one up does it come back down smoothly or does it stick? Does one come down faster than the other? Is there oil in the dampers?

I looked and fiddled with the dampers.. damper on front carb has black sticky oil all over it.. rear damper seems cleaner.. They seem to move about the same.. I looked down the dampers, can't see any oil but as I put the plunger and caps back in, I get resisitance at the last 3/4 inch before I start to thread them.. I have been using 20/50 oil in the dampers as per the Haynes book.. should I be using a lighter oil.. could I use a spray cleaner / degreaser to clean the pistons.. would this make any difference??

I am going out for a drive this afternnon... When I get back I will check the spark plug colour, as suggested in the Archived Post

Cheers Jeff
J Lanaus

Black sticky oil would make that carb piston rise slower than the other one, I would think.
Tom

Could also delay its fall, but neither should have any effect on starting, only running. When starting the throttle should be closed, and cranking like that the pistons will hardly move, less even than at idle.

Anything black and sticky should be cleaned off, carb cleaner would be a good bet. Also remove the piston cover, spring, and piston with needle and clean that and the internal body of the carb.

Clean 20W/50 (or whatever grade of engine oil is correct for your local climatic conditions is fine, if you use too thin an oil you will get stumbling on acceleration.
Paul Hunt 2

Thanks for the advice.. I will pull apart the carb and clean and then pu some carb cleaner in to clean out the internals..

cheers jeff
J Lanaus

This thread was discussed between 15/07/2007 and 17/07/2007

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.