Buying an old Rotax 503

Hello, all. I have a line on a used microlight in France with a Rotax 503 which has has been little flown over the course of 20 years. I am told that the current owner does turn over the engine from time time and it runs fine, though I'll have to see that for myself.

What should I be looking for when considering the purchase of a used 503? What are the must-do overhaul items for a 503 that has sat more than it has flown for a long time?

I'll need to take it to a Rotax shop, I am just trying to get an idea of what i may be in for.

Thanks!

Matthew

Quote:

Originally Posted by cluttonfred

Hello, all. I have a line on a used microlight in France with a Rotax 503 which has has been little flown over the course of 20 years. I am told that the current owner does turn over the engine from time time and it runs fine, though I'll have to see that for myself.

What should I be looking for when considering the purchase of a used 503? What are the must-do overhaul items for a 503 that has sat more than it has flown for a long time?

I'll need to take it to a Rotax shop, I am just trying to get an idea of what i may be in for.

Thanks!

Matthew

Matthew let me be the first to help you here. I see no one else offered any help.

Rotax states that any of thier engines after 5 years needs to come back to them for service or to a service center for service. What happens is the seals will dry out and leak, then you will never get the mixture set right for you have a air leak.

Even a Brand New engine setting on a shelf needs this done after 5 years. Could you get by a few more years before this needs to be done maybe, but your butt is in that airplane so do as you see fit.

The other thing is the needle bearings, Going out and just turning the engine over does nothing for a two stroke. You are pumping no oil into anything, just turning over a already dry engine. Myself I would run from this engine. Why.

20 years old it has to be a SI or single ignition engine. It probably does not have mounting holes for a gear box, the last 503 rotax sold had 8 bolt holes for the gear box, the early models either had none or 4.

Myself I would find another engine. Just me

The manufacturer established TBO for all Rotax two strokes is 300 hr /5 yrs.