Montgomery Ward One Lunger missing

[borgward]

I have a Montgomery Ward single cylinder engine retro fitted on a rototiller. Looks like a B&S. It has had a knocking noise for years. Could be rod, piston pin, or a cracked piston. Starts easy. I run Chevron Delo 400 SAE 30 in it. Surprised it has not blown up on me after years of abuse. Any ideas about it. How to ID. Parts availability.

 

[stangguy]

The engine should be a B&S, as most all old Wards were. There should be model, type and serial numbers stamped into the blower housing right above the spark plug. Is it a vertical or horizontal shaft engine.

 

[Bud_One]

Any pics ?