w 124 fuel cut off problem

[Alastair Nether]

I own a 1988 w124 200 saloon petrol with a stromberg carb, there is a fuel cut off solonid at the bottom of the carb which should operate when the ignition is switched off to stop the engine from running on. my problem is that the fuse which is number 11 in the fuse box keeps blowing after about 1 minute when the engine is started, I have replaced the relay and i have replaced the crankshaft sensor but to no avail, i have bypassed the system by fitting a manual push button inside the car has anybody got any ideas what else i might try thans in the meantime Alastair