Rotax 503 Maintenance - Fan and Starter

[@billhuitson5208]

Thank you , very easy to understand, a great explanation of the fan belt mechanism.

[@markmurray8517]

Glad you liked it!

[@jcowan7487]

Thanks for info about the 503. I would enjoy seeing more videos on this great engine

[@johnnyrobertson1409]

Good discussion of common problems that pilots tend to forget and ignore though failures can be costly. Thanks. -Johnny

[@markmurray8517]

Thanks!

[@RC-Heli835]

Thats a great looking engine We had one that came installed in a Ralley 3B Ultralight. Im modeling the engine and plane to fly in Phoenix RC Simulator.

[@62heliman]

Thanks for the review, I'm looking at a Titan 1 with the Rotex 503. I'll have to really quiz the owner about all this. thanks Mike

[@Superrandomz768]

Awesome video. Please share more details on engine and maintenance...possibly overhaul.

[@cropduster48sady46]

I would like to see you point out the oil drip holes in the crankcases of the 503, and talk about the importance of these holes for main bearing lubrication. The main bearings tend to run very very dry because of windage effect of the spinning crankshaft throwing every thing away from the bearings. The problem is even worse with a inverted engine. The drip holes don`t help with this problem when the engine is inverted. Your thoughts on this subject please.

[@markmurray8517]

Thanks for the input. I currently don't have any plans on covering the overhaul. But, I can say that in my own experience, I have not had any problems with the 503 in the inverted position.

[@hokehinson5987]

Hard chromed pulley sheeves would be a great after market item to prevent belt degradation due to rust on sheeves.

[@rolandsinclair-brown2970]

Hi Just an input on your commented re the pullies on 503 after 2 belt failures (rust) I had the pullies cromed 4 years later no problems My Airfield is close to the sea North Coates Lincolnshire U. K

[@richardballmer5540]

thanks, good info. i just got a challenger 2 with a older 503

[@ernesthiggs7677]

Mark, I'm one of those people that needs to see something done to understand it. If you install a GPL Electric Starter WITH Pull Start on a Rotax 503 PPC would you make a full video from beginning to end on the full installation? With KZbin available, you would think GPL would make a video. Thank you Sir

[@destroytheilluminati770]

i have seen the GPL starter cup that bolts to the mag/flywheel shim develop cracks, even seen 1 example blow apart and damage the fan housing. Another starter that is very rarely seen is one called air redrive, this system has a 1way sprag needle bearing cup mounted to flywheel and it is driven by a toothed belt driving a toothed pulley off starter motor, that 1 way sprag bearing fails easily and sometimes locks up causing the motor to suddenly lose rpm during flight. If you have an air redrive starter system, take it off and throw it in the junkpile

[@hesjevoll]

Thanks i have a 503 in a 87. Escapade

[@arsyadtech]

Great machine and good job

[@embededfabrication4482]

how can you tell when that fan bearing is nearing the end of it's life??

[@way2manyhobbies]

great video. after i flew today i found my gpl starter was loose. Wondering why the allen bolts arent replaced with AN bolts that can be safety wired. You recommend just using loctite 682? btw, i have a spare 503 that was pulled out of service with no issues at 600 hours that i"m planning on getting to you for overhaul.

[@claeyer3866]

If you install the electric starter , can i still use the pull starter ?

[@markmurray8517]

Yes, pull start can still be mounted. Assuming the structure allows sufficient space for it. On the Challenger design there is not sufficient room for both the GPL and pull start

[@paulsheather7657]

you hear people always talking about 2 stroke engines and how unreliable they are. So my questions is what is the number one thing that pilots do to make these engine fail. the reason I ask is I am thinking of buying a flight star with a 503 and really learn more about these engines.

[@markmurray8517]

Great question! Number one problem that I see regularly is more with fuel and air supply than the engine it self. Fuel hoses, fuel filters, and airfilters have to up to the job. Secondly, the engine needs to be run at the temps and rpms that Rotax suggest for long life. Lastly, they need to be run often.

[@paulsheather7657]

@@markmurray8517 Thanks for the quick reply mark. I have been told people tend to leave aircraft sitting for long periods of time without changing the fuel or checking float bowls and try and fly the aircraft which can lead to engine failures.

[@wiley0714]

Does rotax still make the 503? I was considering a Ultralight powered parachute with a 503 but was told go with a 582 as 503’s are no longer “supported “ what that meant im not sure.

[@curtstauff8982]

Stopped making it in 2011.

[@ernie2147]

Would you recommend a Rotax electric starter over the GPL?

[@markmurray8517]

I've used the Rotax starter without any real problems. It usually comes down to installation. Some designs, like the Challenger, don't have room for the starter mounted on that end of the engine. The GPL places the starter at 90° to the engine, which will work with the space provided.

[@samean6749]

😄