your seals are good because it idles low. bad seals it won't idle, i think your problem is dirty carb(s). hope it helps. my 340 rotax had bad seals would not idle at all.
that's because the machines are too big in cc's and then too fast. the government should say that the 340 be the biggest and that's it. make the chassis the same as the new machines for handling and a 340 the biggest engine. the country would see alot LESS accidents for sure!!!
this car is my neighbour's. i remember it when i was like 7 yrs old. i'm 40 now and he drove passed me with it this summer still runs good only about 30000miles on it. and yes it is all original!!!! it's an awesome car.
owning any ski-doo product is a good way to stay in shape , i know i got a 1977 340 and it is about the same way to start!!!! lol