My brother and I bought a 1990 Yamaha Ovation about three years ago. It was a beater we bought for ice fishing. We ran it three times that winter and for the most part, ran well enough for us. It had a bad gas leak. The following summer, I replaced the fuel lines and found a split line that was the cause of the leak. It then sat in my shed for 2 years. I got it started a couple weeks ago and it ran, but smoked like crazy and after somewhat of a warm up would bog down when squeezing the throttle. I finally got it to move, but it was just lurching ahead a little at a time. I picked the track off the ground and squeezed the throttle to the handle bar and it cleared up and the track took off. I then was able to run it around the house a couple times then parked it. Went out a couple days later and started it without much trouble and after warm up got it into the garage. I took off the carb and air box and the box had acorn hulls in it and the carb was pretty dirty. Cleaned the carb and the airbox. Then cleaned the surfaces of the clutches. When cleaning the carb, I noticed the main jets had the same numbers stamped on both of them(174). The service manual calls for different numbers for right and left depending on elevation. The pilot screws I lightly tightened down and backed out 1 3/4 turns per the service manual. I started it up and it idled for a bit then wanted to puke out. I kept it running by feathering the throttle and it wanted to bog down. It was still smoking pretty good. I buried the throttle and it finally cleared and I made 4 laps around the house with very good power and no smoking. When I stopped to see if it would idle it just quit. Couldn't get it started back up and had to drag it back into the garage. After sitting a bit I was able to start it back up, but had to feather the throttle to keep it running. Anyone have any suggestions? This is strictly a ice fishing sled. I would like it to be reliable and right now,its not. Should I pull the exhaust pipe and make sure it is clear? Would a clogged pipe cause this problem? Sorry for the long winded question. Thank you in advance.
Throw that funky "Teikei" carburettor in the trash can and put in an ordinary Mikuni VM-32 or VM-34 instead.
You can take a used Mikuni VM-32 or VM-34 carb from an Ski-Doo / Polaris / Arctic Cat / John Deere....
Preferably you choose a carb from a model with single mounted carb from a similar 340~370 cc engine.
Just use the intake manifold from an scrapped Yamaha ET-340 engine.
+ a carburetor flange made to Mikuni VM-32/34 dimensions ( Kimpex part # 07-100-13 ).
+ a throttle cable ( Kimpex part # 05-138 ).
ET-340 was not delivered from the factory with Mikuni VM-32 or Mikuni VM-34 carburetors !
...However, you must use the intake manifold from an ET-340 to get this Mikuni conversion to work on a Ovation/CS-340.
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I picked up the parts to do this "conversion" but never did it. I could never find any jetting info and I'm not a jetting guru nor plug reader.
Yamaha Nutz
New member
nothing wrong with the stock dual butterfly carbs .... if it is loading up that bad i would think yo have a needle and seat issue or the fuel screws are not set right ...many needed tweeking after the initial setting from the factory the main jets should be the same on both sides. and depending on the year they use different pilots and mains. Also check the carb on the inside of the bore where the fuel screw tips come threw there should be just small little holes, if the casting is chucked out from someone over tightening the fuel screws then the carb is junk