1967brutus

So... you're selling a worn out 85 pound engine for which the worn out parts cost 60 pounds to replace?

Apologies if this comes across as a bit brash, but...IDK, that seems like a really dumb idea to me: If the buyer knows what he is doing, he's not going to pay more than a tenner for it because he'll be spending 70 pounds on a set of bearings and a new P/L set to get the engine in good condition again, which gives him a saving over new of a whopping 5 pounds. Which is not worth it, so he'll refrain from buying it. IF he knows what he is doing...
And you still have to spend 75 pounds of your own money to get a new engine. Better to just shill out those 60 (or 70 if you need bearings as well) pounds and keep your own engine in good condition. Cheaper for you in the end.

If you were going to ask anything over 15 pounds for that engine in worn out condition... well... there are words for that, none of them very friendly.

You could however, sell the engine for a fair price while it still has a decent amount of life in it, let's say you sell after a year for 50 quid or so and THEN get yourself a fresh engine which only costs you about £35. That way you have a yearly cost that is overseeable while having a new engine every year, while the buyer saved some money by buying a decent engine for less money than new.