I would like to get a Moki 2.1 engine and i just found out about the Mark 2.1 engine. Both engines look excatly the same (maybe made by the same company?)
Can anybody tell me what is the difference between these two engines ,if any?

Thank you

They're supposed to be one and the same. Only a name change for marketing purposes in the USA.

Panda is right. No difference except the name cast in the side.

From what I understand the Moki was originally designed to use zero or low nitro fuel so had high compression. This made them run bad in America where the usual high nitro fuel was used so the importer (a Canadian from memory) asked Moki to redesign the head with lower compression just for the American market. Apparently Moki also modified the casting moulds to differentiate between the two types.

Mark and Moki are still designed/built for 0% to 5% nitro. The Dave Patrick models with blue anodized heads are different compression ratio for more nitro. Mark/Moki engines built most recently advertise a different alloy or different finish on internal parts (I think only piston and liner) that allows use of synthetic oils as opposed to only Castor oil in the older versions.