What stand the engine beside me - Rotax ???

It sounds like the timing has slipped, but it could be so many things. The title is just the engine, it is useful to know what on as some things have history. Bombardier-Rotax 511 engine on a '??'.

https://www.google.com/search?q=Bombardier-Rotax+511+no+start+and+backfires

Service manual and owner manual for 2002 Traxter XL and XT.

https://www.google.com/search?q=Bombardier-Rotax+511

..

The engine in a 2004 JD Buck should be a Rotax 650, which is a 2 cylinder 4 stroke water cooled engine generating 62 hp. With that said, the most likely cause of oil in the air filter and leakage from the top of the motor is excess pressure in the crankcase. A cracked block is a possibility, but the most likely culprit is worn piston rings. A compression test should help narrow it down, but in either case you are looking at a complete tear-down of the engine.
https://www.rotax.com/en/products/rotax-powertrains/details/rotax-650.html

A Rotax motor with dual carburetors... sounds like one(or both) of the carbs needs a little TLC.. take this engine to a qualified professional..they will take care of what ever ails your engine...

Hi Faye,

I found this,





Rotax spark plug advisory for ultralight, experimental lightsport, amateur built aircraft.




Rotax 2 stroke aircraft engine spark plugsThe recommended spark plugs for the Rotax 277, Rotax 377, Rotax 447, Rotax 503, Rotax 532, Rotax 582 are the NGK B8ES series or the NGK BR8ES ( the R in the spark plug denotes it is a resistor plug and should be used in all of the CDI ignition engines.



BUT the Bosch points ignition engines should NOT use both a resistor plug and a resistor spark plug cap - use one or the other.

The least expensive option in the long run is the cap as you purchase it once while the resistor plugs cost more than the standard plug each time you buy them.


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Use spark plugs that have a SOLID TIP - DO NOT USE spark plugs that have an aluminum screw on tip. They vibrate loose, the tip wears making a loose cap to plug fit, and can lead to the spark plug arcking across from the cap to the plug. Also the screw on style spark plugs are NOT designed for our applications, the gap is generally set up for .030 to .035 thou. The solid tip spark plugs are set up for a gap of .015 to .020 thou.

Spark plug gap

• Allowable range: 0.4-0.5mm / .015 -.020"



• Optimal: I usually set them to .015 and let them wear out to .019



• This also helps getting the engine started in colder conditions

This was found at

Did you get the Rotax 912S overhaul manual?

Jet size varies depending on modifications and air density. We use a Mychron w/head temp gauge to keep an eye on our kart jetting on a Honda Clone. There are probably some sites out there with forums that deal with Rotax on karts. They may can help. Four jet sizes seems a big leap to me on a guess but then again I've never dealt w/Rotax.
Check out this site for all the torque specs -

http://www.ultralightnews.ca/articles/torque.htm

88 /89 af1 sintesi & futura both use rotax 123 engines and parts,