1999 Yamaha Big Bear 350 Won't Start


Old 07-19-16, 08:17 AM
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Join Date: Jul 2016
Location: USA
Posts: 2
1999 Yamaha Big Bear 350 Won't Start

I've "inherited" a 1999 Big Bear 350 which has been sitting for about a year. The fuel tank was dry when I opened it up, but I don't know how it was done.

Upon initially receiving the vehicle, it would not start by pulling, and got no response from the push button start. The Neutral and Reverse lights never light up.

I have replaced the battery and spark plug, cleaned the air filter and associated box. I cleaned the carburetor, except for one jet, which I didn't want to mar while trying to extract with an improper tool. I poked a wire down into it, and sprayed it with an excessive amount of carburetor cleaner.

I opened up the fuel valve and ran fuel through it to make sure it worked properly and was truly dry to begin with, and also to clear out any debris that may have deposited inside. This seems to be working properly so I filled the tank with new fuel.

After all of this, I have jumped past the starting relay, and get the starter to turn over, but the vehicle won't catch and run.

I have two theories I'm running with -- the Neutral Safety Switch (or Gear Position Sensor) and Reverse Switch are faulty, or an issue with the spark/carb still. I have not checked for spark since installing the new spark plug, but I believe that the Neutral Switch issue would prevent it from getting a spark, even bypassing the starter relay. I could be wrong about that though.

Going with the Neutral Safety Switch, in the back of the engine on the right half I've found a stud with a male spade sticking out with a single wire attached to it, which when removed appears to be a simple brass bolt. I believe this to be the Reverse Switch. I've checked it and it has no continuity between the spade and the inside flat area. I believe this is proof that it is faulty, but I'm not sure of proper identification nor troubleshooting test.

If I look just above this I find two wires going through a rubber grommet into the engine. I opened this up, lost all my oil (which is fine, I was going to change it anyway) and saw that the wires ran behind a couple of large metal wheels (I'm an electrician, not a mechanic, so bear with me here, please.) I believe that to be the neutral safety switch.

If I am correct about these items, I need to replace them, and have no idea how to get to the neutral safety switch. Are these what I think they are? Is there a way to bypass it/them so that I can make sure that it is the culprit? How do I remove the gears/flywheels to actually get to the device?
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Old 07-19-16, 01:28 PM
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Join Date: Oct 2002
Location: Hamilton County, Ohio
Posts: 4,288
Welcome to the forums. If you do not have a manual, check the attached link.

The first thing I consider when most electrical components do not work is the fuse(s).

There is a main fuse under the seat. check the manual - I think it's page 145 - for additional fuses.

Old 07-22-16, 07:11 AM
Thread Starter
Join Date: Jul 2016
Location: USA
Posts: 2
I've checked all of the fuses with a meter and visually. All of them that I can find are good, including the main fuse. When I turn on the main switch, all of the lights work, headlights, tail lights, and indicator lights. When I press the start button the oil light works, so I swapped leads to the other two lights, and used that to test them, both lights are operational, the reverse and the neutral.

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