Rotax max starting problem

[G3pex]

I have just bought a rotax max 125, it started up really easy. I went out on it on the track and on my way back it died. Ever since then i cant get it to start again. Can anyone help me please

email
gp-super-sales@live.co.uk

[Clay Maddox]

Have you installed a new spark plug and tried that? Being new to Rotax, you might be running it rich and/or not running it hard on the track. Both of these will load up the plug and not allow it to burn itself clean.

The Rotax is finnicky about spark plugs. You can take a plug that will not start a Rotax but put it in a Yamaha & the Yamaha will start fine.

Try that first. It is quick and easy countermeasure.

[Marc Miller]

Originally Posted by G3pex

I have just bought a rotax max 125, it started up really easy. I went out on it on the track and on my way back it died. Ever since then i cant get it to start again. Can anyone help me please

email
gp-super-sales@live.co.uk

Some simple things. Check all wiring connections. Make sure choke isn't still on. What jet is in it? Has it sat for a long time? Is the battery fully charged?

[G3pex]

The spark plug is sparking I have already checked that. But I have just purchased a new one to try. When I bought it had been stood in his garage. The guy I bought it of started up first time. When I got it home I got it started really easy. Had a few goes on it and on my last go
it just died on me. I fort it was low on fuel, so I put some more in and ever since then it won't start. What else can
I check. The choke, when the chokes is on should it be in the veritcal postion? Thanks

[G3pex]

I have put a new spark plug in the rotax max. Still wont start, i have spray fuel into the carb and it starts up, after a few secs its stops. This make me think theres no fuel getting in.

[Jean Stafford]

Ours has started first time, every time, so far.

How much oil are you using in your gas? What brand of oil? Use Moutil 800, at 3 oz/Gal. Works very well with little carbon buildup. Any other oil especially Castor, can cause prtoblems.

Pull carb off, to check tor a broken reed. Unlikely, but possible. Take to a ROTAX dealer for this repair. Hew can re-seal the motor and insure legality.

Make sure there's a good ground. Make sure the timing lead is secure on the motor.

Only reasons a two-cycle engine won't start:
No fuel
No Spark.
Spark not at right time.
no crankcase pressure to transfer fuel within the motor.

[Chris Lobaugh]

More than likely the needle valve is stuck closed. Pull the carburetor off the engine, remove the bowl and floats, turn the carburetor upright again and check to see if the valve is returning properly. If everything looks okay there I would begin cleaning out all of the jets to make sure there isn't any oil or debris plugging the holes. If everything still looks good on the carb side it could be oil bulid up in the fuel pump. Remove the fuel pump, pull the 4 screws out, then split the pump make sure that there is no oil residue clogging the pump.

Put everything back on the engine. Prime the tank by blowing into the vent line on the gas tank. Fuel should leave the tank, fill the pump, then you should see the fuel travel from the pump to the carb and fill the bowl. Pull the choke up and turn the engine over with NO THROTTLE. Once the engine fires leave the choke up for about 5 seconds, then turn the choke off, and begin to feed a little throttle.

As Jean mentioned if one of the reeds are broken (unlikely unless there is alot of time on the engine)it will be difficult to start.

Double check that the engine still has compression...use a 17mm socket and turn the engine over by hand (using the nut that holds the clutch on) you should be able to turn it over but it won't be easy by hand (with the spark plug in obviously)

let us know how you make out and feel free to give us a call if you need immediate assistance

[Jean Stafford]

Here's another thought, learned the hard way. Is there any other rway??

Floats can go in upside down. If this has happened, the inlet needle will be held closed, and no fuel wilkl pass from pump to bowl. You can grind forever, and it won't start.

Check by putting a piece of fuel line on the inlet, and testing with a pressure tester. With no fuel in the bowl, you shouldn't be able to get any pressure.

(The little tabs on the floats should be toward the bottom of the bowl. Not the other way round.) (Oh yeah. They should be facing toward the center as well.)

DUH!!!