Rotax 503 experiences and alternatives

[flynow]

Looking for an (minimum) 50hp engine and wondering if anyone has experience with Rotax 503. In case I can't find one to purchase or it's not a good engine, is there a good alternative for less than $5K?

Thanks!

John

[Dana]

The 503 is a very good engine, probably better than any other engine in its power / weight class. The 582 is similarly reliable if you want a bit more power. Being 2-strokes, they do require care and attention different from 4-strokes.

If you can afford the weight penalty a 4-stroke like a HKS or VW would be my preference, but you won't find a HKS under $5K, VW maybe.

[turtle]

I buy every 503 I can get my hands on. Always someone parting out a crashed ultralight. Repair what failed and stick it on an airboat. Can almost get a season out of one before rebuilding the top end. What size boat are you planning on putting it on?

[melann]

I will say this. Back in the day, I was a dealer for Spitfire Ultralights. I ran quite a few Rotax 503s. I found that the single carb version put out the same hp as the dual carb version. The only difference I found is that the dual carb version burned much more fuel and had to have the filters cleaned much more often.

[flynow]

I buy every 503 I can get my hands on. Always someone parting out a crashed ultralight. Repair what failed and stick it on an airboat. Can almost get a season out of one before rebuilding the top end. What size boat are you planning on putting it on?

Minimax 1650 EROS.