JAP Nash Boadicea Rotary mowers seized

from my experience recovering old engines, there's a few methods. the first and second I prefer to use. method 1 concerns the use of an oxy acetylene torch with a rose bud flame heating the piston carefully and the casing to hopefully free the cylinder. method 2 is to remove the electronics, drain oil where applicable and fully submerge the engine in an ultrasonic bath like I use in my workshop. using a light acid to heat and clean debris, it is possible to free up the piston.

a decent way of doing so involves removing the head and head gasket where possible, draining the engine if applicable, dismantle the bottom end so the con rod can be removed then with a bit of heat and a wooden or high density plastic bar and a dead blow hammer, strike the piston with the protective implement and hammer until the piston exits. this is where you'll need to inspect the piston and walls for warping, cracks, etc. if there's damage, the best thing without serious cost is to scrap the engine. if you're into lathes and milling machines though, re reaming the block would rescue you but this is an experienced art form so I'd advise finding a precision engineer where possible.

ed

Hi Ed,

Thanks for the advice, I managed to free one of them up today whilst trying to remove the blade which is connected to the engine shaft, I was using a socket to undo the nut and It required so much force it freed the engine. Got the other one to tackle yet and all the other problems that will arise! I might go for the make one out of two method.

Henry.

ewell done, sounds like a good plan. sometimes an engine seizure is due to blade drive or gear drive faults, others it's the piston swelling in the pot, others, it's the con rod failing, etc. come across various issues in the past and in some cases it's worth abandoning.

every confidence in you. keep up the good work.

ed