I have a moki 210 which ran good last season only about 2 or 3 gal. threw it . I tried to start it up today and it would not start not even a pop .
It also has almost no compression . The piston and cylinder look fine could it be that the piston RING needs to be replaced.
If so where can i get one
Tony...

A suggestion. Maybe the ring has gummed up with castor? I ahve a brand new one of these, unrun as yet for my 27% Extra.

Try Just Engines in the UK for spares.

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I agree with the other poster. Most likely it is gummed up and the ring is stuck, hence, the low compression.

OR, you ran the engine way too lean during its last flight and damaged the ring's metal tension. This tension holds the ring against the cylinder wall and provides the compression that is needed to run properly.

The first possibility, a stuck ring, is easy enough to solve. Pull the glow pug and drop some fuel into the cylinder. Give it some time to see if the fuel breaks the ring free. This is the most likely problem.

If this doesn't work after multiple tries, it is time to send the engine back for servicing. I do not recommend replacing the piston ring yourself in such an expensive engine unless you are a professional cycle or automotive mechanic. It is easy to damage that expensive cylinder wall.

On a ringed engine that size, 2 or 3 gallons would be barely enough to run it in let alone wear out the ring. Engines don't wear out from just sitting so I'd go along with the stuck ring. If you can't free the ring by soaking with fuel and flicking it over for a while then the next thing I'd do is to take out the piston and gently push on the ring with a finger nail to get it to move in the groove. Sometimes they can get gummed behind the ring and this doesn't let the ring expand outwards all around. Usually they'll expand at the ring gap a little so put fuel in the gap and push the ring inwards at the gap. This will slowly allow fuel to get behind the ring and dissolve any gum.

I had exactly the same problem on my 1.35 when I changed the oil I was using (changed from Castor to EDL). I always hand start my mokis, but putting a bit of fuel directly through the glow plug hole, then putting the plug back in, followed by Two / Three turns on a friends electric starter did it!

PS: I have 3 moki's all now running on EDL with 5% they have never performed better, even better throttling characteristics!

Hope this helps.

W

Thank's to all.
I soaked the engine over night and next day put my big dynatron starter to it I finaly got it running ,ran it very rich to get the ring free
after 5 min i stopped the engine and the compression was back
You learn something every day Thank's RCU and all it's great members.