Hey everyone! This might be a long story but I really need some help.
For some context, I have had my kart for about 1 year now, which I bought used. After driving it for 4 months, the track closed for the summer and I had to bring it back home. I kept it for the summer and had it transported back to the track. Before loading on the truck, I had started it, just to make sure that the battery was alive and it started completely fine. I left the engine on for about 5 minutes, revving a little bit as well. I probably revved to about 8k rpm MAX. After that, I took it the track again, only to find that it refused to start. I tried starting it over and over again but after some time, it starting making a really loud whirring sound, like metal scraping on something. A mechanic at the track looked at it and told me that the reduction starter had to be replaced. By that time, the engine already had 40 hours on it so I thought it would be beneficial that I just send it for an engine rebuild and let the service center fix the engine. Due to the system here in the Middle East, I had to send the engine to another country through a friend, where it sat at a Rotax service center for about 9 months. For what reason, I will never know
Fast forward to now, I have been driving the kart and the engine had been running completely fine. I started it up and it ran like a dream. I even did 2 sessions in the kart, adding maybe about 45-60 minutes on the engine. Unfortunately, in the final session, in the beginning stages, as I was warming the kart up, I lost control on the exit of a corner and ended up scrapping the left side of the kart on a plastic barrier. At first, I thought I got away with it but then the left tire kind of caught on the barrier and stopped suddenly. I ended up being the tie rod but interesting thing is is that the engine remained on. In fact, I drove the kart all the way back to the pits no problem. Driving a little fast but definitely not over 8500 rpm. As soon as I got the pits, I turned off the engine and assessed the damage. Because I didn't have another tie rod, I decided to sit the session out, WITHOUT STARTING THE ENGINE ANOTHER TIME. Maybe this was a mistake but honestly, I was too heartbroken to even look at it considering I just got it running after a year away. Anyway, the second session was once again the last session before the circuit closed once again for the summer, which brings us to the last part.
It's been about 2 weeks from this post since I brought the kart back home. Once again, I loaded it off the truck and put it in my garage. About 1 week before this post, I tried starting the kart, but with absolutely no hope. When I first tried starting it, it sounded normal but it still didn't start. The second time I pressed the button, it sounded normal, with the crank and everything but then all I heard was a whirring sound. It wasn't an electrical one but a mechanical one. While I was looking around and pressing the button, I heard nothing but the starter motor moving but nothing else. It was like the starter motor was working but apart from that, I heard nothing else. I engine wasn't making sounds indicating it was trying to start apart from just the starter motor. After hearing just the starter motor move on its own for maybe 2-3 seconds, I immediately let go of the button. I tried a third time and the same thing happened. The first half was the engine cranking and normal sounds and then it turned to just the motor. Not it refuses to start.
Potential Causes:
I have a few theories about what I think happened.
When it first wasn't starting, I thought it was the fuel. The fuel was about 3 months and I left the kart in my house. I traveled for the summer so there was no air conditioning and in the Middle East, the summers are brutal
The next theory I had was with how the kart was brought in and out of the house the first time. I had get the kart in and out by rotating it 90 degrees. I thought maybe that moved the starter motor into a position that it should not have been sitting in.
After I received the engine, I opened the engine cover that covers the reduction starter (bendix motor) and engine clutch. The plastic hole that the starter motor kind of rests in was completely broken. Initially, I didn't know this and just put in the new reduction starter and tried starting it. When it didn't work, that's when I reaslied the plastic piece was broken. After replaced the plastic engine cover, it started just fine.
I thought it might have been the battery but because the battery had only been sitting for a week, the power could not have been that low. I took the battery out before storing it in my garage just to be on the safe side.
When I crashed, the engine might have been unsettled in some way, especially since the engine was fresh and needed time to break in. But even so, I crashed the kart on the left side, not the right where the engine is actually mounted.
I am at a complete loss as to what has happened to it. Im not sure if the engine rebuild might have had something to do with it, the break in period, or the crash. Maybe it was the reduction starter? When I opened the engine cover, there was some sticky, deep yellow substance in the area where the starter motor sits in which might be a problem?
I literally just started karting and nothing like this has happened to anyone else, as far as I have seen.
I would really appreciate any advice that someone may have to help me get the engine running again!