mountfield emporor 21" engine repairs?

The piston & rings may or may not be toast. The big end WILL be totally shot, and the PTO main bearing (n the sump pan) will probably be beyond salvation. You will need more or less the complete set of internal parts, and even then it will probably smoke heavily because the replacement piston & rings will not have the same wear pattern as the cylinder.

A new engine is the only sensible solution, but you need an auxilliary PTO engine, and they haven't made them for years.......

Best compormise - examine the lower main bearing when you get the sump off. If it's OK, find a standard (non aux PTO) engine of the same type. Swap the sump pan (complete with PTO components) and camshaft (with the drive gear) from your existing engine. Take note of any shim washers.

phil_saunders(a)bigfoot.com

Phil Saunders
November 2009

You seem to be scavenging parts from another engine?
Make sure that crankshaft end is bare and the woodruff key removed. Undo the bolts that secure the end aluminium plate to the cylinder block and pull it clear. Remove the cylinder head. Undo the 2 bolts from the big end bearing / connecting rod. The piston plus rings can be withdrawn upwards through the top of the cylinder. I would advise changing the crankshaft too as they don't have separate bearing shells.

John
October 2009