Hi,
I'm trying to fix and understand a problem with my bf100 1984 motor. I bought it used, and the neutral switch (part #35100-881-003 ) is broken.
I was wondering what was the use of that part? is it only linked to the dc output to shut it off when motor is on iddle or does it have another function related to it?


Finally, engine runs smooth without the engine cover, but as soon as it is put on, the motor barelly stalls. Rev really slows downs and lose power. I checked for any short circuit, everything seems ok. I also checked for any leaks on the exhaust, thinking the carb might have recycled exhaust fume, but everything looks alright on that as well. Even in high wind conditions on the water, it refuses to work well with the cover. i don't get it......!!!!

Thanks for any clues.....

Ok ok, after some fidling around, unbuilding barely the whole thing i somehow start to really understand how that motor work......not that complicated....

Ok so for the broken neutral switch, motor seems to be unstartable when the wire of the switch aren't shorten together. So to start the motor or to put it on the neutral/idle, those wires have to be shorted. it doesn't seems to bother once motor is running. or does it?

And for the cover problem, yes, the exhaust was leaking back to the inside case by the hole of a missing bolt around the vertical shaft and under the Main body/case/oil case. I had to remove the extension case to see it.

Still wondering about the neutral switch....

The neutral switch is a safety feature so that you dont start the engine while it is in gear. It opens the circuit when it is in forward or reverse, and disables the ability to start the engine. When you go back to neutral the circuit is closed, alowing the starting of the engine.

The reason for this is to prevent damage to the engine if you try to start it in gear.

Thanks for the info...

I came up to that conclusion too as it didn't do any change if i did or didn't shorted it while it was running in Forward at full throttle.....I had the brilliant idea off putting a mechanical switch wich appear to be quite unuseful.

It is quite a tough mechanic as mine is a 1984, it has been dropped to the ground or in to the water, because the oil case misses some metal ...and it still start at the first pull of the starter rope.

Can anyone help me get the engine cover off my BF115a? the front lever unlocks but the left side lever is looser than it use ti be and in not working to unlocking the engine cover. thanks Mike

oh man, yep the nut is not right, keep tiring to unscrew the handle and then you can get a pair of pliers in there and turn the latch