Hi guys,
I am fairly new to Superkarting, but thought Id inquire about an odd problem I am having that I just can't seem to figure out.
My Rotax 125 was running fine until I manage to come off the track and onto the dirt. At which point it died completely and would not start up again. Easy fix, took it back to the pits, cleaned the carby, checked for any loose wiring or damage and off it went again.... for about 1 min ( I got to the pits from my garage). Back into the garage and another carby clean later, it seems to be running fine once again... but only on the stand. As soon as the kart is placed on the ground (with any sort of load), the kart struggles to go anywhere. Full throttle is barely walking pace.
I've cleaned the carby thoroughly (all jets, needle, filter several times.. even tried different main jet). Cleaned out the power valve and readjusted, cleaned out the air filter (couldn't clean the actual filter at the track) with no luck. Checked fuel is definitely getting to the carby (no blocks or fuel pump problem). After getting home, I checked the battery to ensure it was outputting 12 V (not sure how to test the battery during operation however... so I am not sure if those 12V are getting to the engine).
Has anyone experienced this kind of problem before? It runs flawlessly on the stand (no power loss when throttling), but struggles under load. Last time I had a similar problem, an ultrasonic clean of the carby seemed to have fixed the problem so that'll be my next step. Could it be clutch related? Could it be electrical?
Any help would be greatly appreciated.
Comments6
Re: Rotax struggling under load
Ill get the muffler checked out to see if that may be the cause. Thanks for the advice.
What exactly is the stinger responsible for? How does it affect the performance?
Re: Rotax struggling under load
You said that you ran off the track and onto dirt,sometimes dirt can get sucked up between side of the filter and the airbox.You may have sucked some dirt/dust into the motor and scored the bore.
Re: Rotax struggling under load
Also are your floats in the right way??? If you blow the fuel up and they are the wrong way the bowl will fill but not accept any fuel when you start the motor from the pump so you can run it for a couple of minutes on the stand and when you put it on the ground there is not much left.
Check the rubber gasket between the throttle body and the carby body. If it is not lined up correctly it will give the same problem you are explaining.
Batteries usually are either working or not but when there is a small break in the bars or it is getting down on voltage you will get a miss at high revs.
A broken stinger usually gives less power at top end.
Re: Rotax struggling under load
The floats in the carby seemed to be correct, fuel was going across fine (wasn't flooding). Nothing seemed to be wrong with the throttle body connection.
I suspect its either the battery or the carby. I am getting the whole system tested through a dyno run over the next couple of days ( I wanted to do a checkup before getting into competition anyway) so hopefully any problems will be determined then. I've asked for the ultrasonic carby clean and a load test of the battery just to be sure.
Ill get the stuff back on the weekend (hopefully) and will update you guys on what the problem was. Thanks for all the input! I really am getting to know the components of the kart a lot better through this. Appreciate it.
Re: Rotax struggling under load
Re: Rotax struggling under load
However, inspection wise it looked fine. Not sure how to test it thoroughly. However, the loom went in with the engine for testing so I am hoping the dyno is able to detect any voltage drops in the wiring loom as it should have an effect on the engine output.
Certainly will be interesting to see what the problem was/is.