spark arrestor plugged?
Pull the belt and measure it's width? And for hourglassing? Hourglassing is very common on CVT's, due to folks using them for tractors and such. Machine sits still, clutch engages and puts a bunch of friction and heat in one spot, narrows the belt in that ONE spot. When this happens, on some machines it causes the crankshaft speed to flucuate, which causes (A) the engine to run weird and (B) throws a check engine light, a misfire code, and occasionally might go into limp mode. This is done because they have a catalyst built into the muffler, so the ecu is programmed such that when it 'sees' a 'misfire' (whether it really is or not), it doesn't keep pouring raw fuel into the catalyst, which burns it up. It will actually melt the cat. On this note, on all cvt equipped machines, low gear is your primary gear when you are below about 20mph. High is just your road gear. It's nothing like a truck where you're in high all the time until you need more pulling power; it's actually opposite-low being your primary gear. Using low will drastically reduce the loads placed on the drive belt.
Not saying that the belt IS your issue, but I did want to point that out for those that may not have known.
and, you can't go by smell because newer engines are totally different. Smell means nothing anymore. Don't rely on it, at all. The catalyst in the muffler changes that smell, as do a lot of other things. And yes almost everything has a catalyst inside the muffler nowdays. Mowers too in some cases. In the old days you could kind of gauge how the mixture was by the smell, but that's not the case with ANY EFI stuff anymore. I don't care how 'good' you think you are, I can almost guarantee you that an EFI engine that "smells" right to us old timers, is rich or has retarded timing-or both. Just as an example, my old car-carbureted 302 ford, it smells normal, and it runs normal. To me. On my EFI car, also a 302, but has cats (factory EFI), if I go in and adjust the mixture via computer to smell like the old one? It's lambda is around .80. 1.00 is stoich. .80 is rich. Also on EFI stuff, your ignition timing can be whatever the ecu wants it to be. At idle, it wouldn't surprise me to see it at 40 degrees or so, and it might be different for each cylinder (polaris is definitely different for each cyl). LH cyl might be at 10 deg, RH might be 4 deg, at idle, simultaneously. My car? Factory EFI, at idle, varies between 30 and 45 degrees. It uses timing to maintain the engine idle speed. At cruise it is sometimes 45-50 deg.
This is where Kubota doesn't have a lot of good data log software (or didn't when I was with the kubota dealer) to actually watch what's going on in the EFI system. On our polaris stuff we can see everything in real time via digital wrench; and from there "usually" we can see what the issue is. If MAP is real high, we know that the valve clearance may be off, or the throttle blade is open too far, or perhaps there is an intake tract leak. Majority of the time it's an intake leak. Similar on Yamaha stuff, with their software you can see what's going on. Kawasaki's stuff was kind of poor at the time but I understand they finally fixed that, but does the dealer have access to it? That is the question. Kubota didn't have a lot decent software to watch the sidekick's efi at the time, which I asked about and didn't get much answer to. I hope they've addressed that, because if you work on EFI stuff, you NEED the data to diagnose. If you don't have that or access to it, you're just guessing-and some techs, that's all they can do is guess because they don't have access to the data.
The OEM EFI software viewing stuff is EXPENSIVE, and some dealers don't buy it. It's auto-shipped in a lot of cases, but the dealer gets billed for it (usually), and sometimes (like in the case of the kubota dealer I was at--that also had yamaha and kawasaki), they'd get it-then get the bill, and send it back. It's expensive up front, and then you have to pay for a license renewal every so often-typically every year, and that's $500 or so I think, billed to the dealer.
there is one I was looking at on Craigslist…no thanks!
