Inlet Valve Trouble

Hello again all,
I had hoped for a little more run time before major works, but unfortunately not. Long story short, I mended the plunger on the fuel regulator wheel and decided to try a run with fuel in the tank. Filled tank, tried to hand prime carb but pump not working. Pump removed, gentle prod at both non-return balls to free up, lightly oiled pump rod and re-assembled. Bingo, pump now working. Tried to start but only fired a few times (randomly) and noticed fuel mist exiting the air intake. When I first got the engine it started well but ran very lumpy. I turned the engine by hand and there appeared to be low compression and on the compression stroke I could hear air passing the inlet valve, I also noticed petrol on the valve stem passing the seal . Hopefully, after dismantling I can re-lap the valve but I wonder why the inlet valve should start to leak?. I guess it's head off and see. Don't get me wrong, this is one reason I bought the engine (to tinker with as well as enjoy the magic of watching it run). I did hope for little more run time first but, Hey Ho, it is what it is!!!!
Any advice or similar experiences greatly received.
Thanks for reading, wish me luck.
Stuart.

Sorry, for those I have not already chatted with, the engine is a 1934 Lister AK

Stuart, your Lister AK is it hopper cooled or tank cooled, either way dont go looking for head bolts/studs or cylinder head as it wont have either. What your looking for is two brass bungs, a very large square piece of bar stock to make a T bar, a lot of heat, you will need a dictionary of swear words and finally a lot of time.
When you have made and assembled the above you can ask more questions

Maryalice

Hi Maryalice,
It's hopper cooled, yes I noticed said bungs, I shall find some square bar and get the welder out to make the tool and have a go when I have some time. Any ideas as to what cause could be? I could have expected exhaust valve to fail but surprised at the inlet, I suppose debris in fuel could be a cause..
I'll keep progress posted.
Cheers,

Stuart,

Try the following, turn the engine over until both valves are shut, get a large screw driver and place between the inlet valve stem and the valve lifter, push the blade in so that the valve is as open as you can get it and then sharply pull the screwdriver out to allow the valve to snap shut and see what occurs.

Maryalice

I had considered that, I've also got the carb and thottle body off and was going fire some electrical cleaner (very quick evaporating) up towards the open valve to see if that might move any debris. I wonder whether there may have been some debris in the pump which has dislodged and ended up on the valve seat. We shall see.
Thanks

Good news I took the plug out and could see the valve, turned the crank so the valve was just open and fired some electrical cleaner in. Result , fires up and runs a treat. Change of mind to run on paraffin so filled tank with petrol and pumps fuel perfect and had a good long run this afternoon. I'm a happy chap today. Thanks for advice.
Stuart.

Well done, you must have been lucky with the plug, bit late now but did you heat soften the copper seal.

Maryalice

I didn't need to remove that plug, I meant the spark plug, sorry, I could just see the valve with the spark plug out and managed to clear it though there thankfully. I had made a hefty 'T' bar just in case so I have it should I need it in the future.