Rotax 503UL post-purchase inspection with NASTY surprise

Inspection of a engine from a recently purchased Challenger II. This 503UL had been sitting for a extended period. Follow along with my dismantling and inspection.

[@metocvideo]

Always good to watch a man who knows what he is doing….

[@RotacRepair]

Thank you for your kind compliment!

[@keithschneider6348]

That mouse did a number on that ignition system. The inside looked great. Good video.

[@RotacRepair]

Thank you!

[@williamwhitley1174]

Great video. Thanks for your careful explaintions!

[@YamahaC7SRG]

Very interesting! Thanks for sharing that.

[@richerone]

Nasty findings, I am sure glad the new owner brought it to you before starting it or flying it! If I buy another plane with a two stroke Rotax, I am bringing it to you for a full inspection.

[@josepsopena6022]

muchas gracias muy interesante el relato 👍

[@JohnBaker-og4zp]

De nada

[@Armilite1]

How about a Rotrax 277UL Rebuild?

[@AhmedAdly11]

Nice!

[@embededfabrication4482]

Does the 503UL use metal ring type head gaskets? I don't see them on my skidoo engine, only the O rings.

[@johnbaker1407]

The 503UL engine uses metal ring type head gaskets only, no o-rings like on your sled.

[@MrHanowski]

What should I use for crankshaft locking pin if I don't have one? What size diameter is the locking pin? How long? Maybe I can just use a proper size bolt? Grade 2, 5, 8? Thanks for any advice!

[@johnbaker1407]

STOP! please use the correct tool only. Why do I recommend using only the $3.12 CDN Rotax #876640 “crankshaft fixation tool”? Here’s the hard luck story. I received a contact explaining to me how a fellow had used a centerpunch to lock the crankshaft of his brand new 582UL. While tightening the propeller drive pulley the centerpunch failed and shattered. He extracted the makeshift tool, now realizing there are now shattered bits of centerpunch inside his new engine. This engine was shipped to my shop where I completely dismantled it and retrieved all the fragments of metal. I then fully assembled the engine and placed it back into service. I’m able to sell and ship to you this tool. It’s likely the least expensive tool Rotax available!

[@RotacRepair]

Stop, please don’t make a lock pin for this. The proper “crankshaft fixation tool” Rotax #876640 is $3.12 CDN. I can sell and ship you the tool. This is the reason you need to use only the correct tool, a fellow used a centerpunch in an attempt to lock the crankshaft. This was a brand new 582 engine. The centerpunch shattered inside the engine when installing the propeller drive pulley. After a phone contact he brought this brand new zero hour engine to my shop. I then dismantled the engine and retrieved the shattered metal fragments from inside the engine. After assembly it was placed back into service. The $3.12 would have been preferable to the fee to clean the debris from inside the engine. Best regards, John

[@MrHanowski]

@@RotacRepair Good advice, thanks. I was advised similarly from another knowledgeable Rotax mechanic. I'll get the correct locking pin.

[@russellhuston6481]

Tip # 1, never use an impact on a torx or allen bolt..

[@RotacRepair]

Thank you for your comment Russell

[@RC-Heli835]

Thanks for sharing. You dont know where I can get some dimensions on this engine do you? Im building Ralley 3B to fly in phoenix RC Simulator. We had one of those and it had this engine on it.

[@RotacRepair]

I would suggest you visit Rotax-Owner.com. Select manuals. I believe the “installation manual” for the 503 will contain the the dimensions you require.

[@avalanche9026]

Hey you paid couple hundred ?? For the damn thing. So what you expect ?? Rebuild ?? Haa.

[@RotacRepair]

We’ll unfortunately they paid full purchase price for this aircraft that apparently only grandma flew on Sundays.