Engine not cranking properly

Hello,

It sounds like you might have some liquid like engine oil, coolant or fuel in one or more cylinders.
What do the spark plugs look like? Are the electrode tips dry or wet? When you crank the engine over does anything spray out of the spark plug holes?

Please see picture of wet spark plug attached

If possible carry out a compression test and forward us the values. How to do a compression test is explained in the below link.

https://www.2carpros.com/articles/how-to-test-engine-compression

Let us know how you get along.

Cheers, Boris