Yamaha Malta 2.2hp 2-stroke problem

[Montemar]

I have a Yamaha Malta 2.2hp 2-stroke outboard motor. It used to work fine when out in Spain where I bought it and a can of fuel second hand.
Now it is back here, fresh fuel, 100:1 2-stroke mixture as it says in the handbook, oil change to leg. It starts, smokes a bit runs for a 20 seconds then starts to slow down. I can keep it going by putting the choke in gradually and opening to full throttle then it stops. It will not restart. I have done this a few times now after heating plug, getting fresh petrol etc. etc.
I would greatly appreciate any help on this as I feel sure it is a simple fault but I am damned if I can find it. I have had the carb in bits, cannot check the ignition but as it starts it would appear to be OK. The only thing I notice is that it smokes but I am sure the mixture is correct.
Please help before I have a Basil Fawlty moment and beat it to death!

 

[davidej]

The Malta has a tiny fuel filter buried in the on/off fuel tap. My one picked up quite a lot of debris and stifled the fuel flow and it would only run with the choke partly on.

If your has one, chuck it away and fit a proper in-line filter

 

[Kawasaki]

If you have to pull the choke to keep the motor running you probably have a pilot air jet problem. Strip and clean the carb properly and make sure all the jets and airways are clear. It's not difficult with that model.

 

[TQA]

When you have the carb bowl off open the fuel tap and check you have a good flow of fuel to the carb. A bit more than a dribble.

 

[Montemar]

Thank you for your suggestions, I shall give them a go next weekend.