1999 Suzuki King Quad 300 - Running Bad

[jfag5093]

I have a 1999 king quad 300. When you start it .it runs fine for a few seconds ,then really starts to miss. I found out that if you turn switch on over to headlight side, it will smooth out and run fine. I checked voltage at battery while running, and got 17.68 volts. could the regulator rectifier be the problem. also , if this is the problem,where is it located.

[Ajmboy]

That's odd, sounds like there is an open circuit somewhere. Do you have a wiring diagram?

[XWrench3]

17.68 volts is way to high. the first thing to check is the battery bolts. if they are even a bit loose, it can cause a high reading. if they are indeed tight, the voltage problem may very well be the rectifier/regulator. i believe on that model it is under the plastic behind the front rack, bolted to the frame. as far as it misfiring /running rough, that is most likely not a voltage problem. there may be a problem in the handlebar switch assembly that may be causing it, you may have a bad ground (by the way, aprox 70% of all motorcycle/atv electrical problems are a ground problem). if you had a bad ground in the right spot, it could be causing both problems. but that is not likely. that in no way means you should not check it out. on my machines, one of the first "modifications" i make is to run one wire, from the negative battery post, to the engine, and then on to the frame. i make this out of a very light gauge, white whire, so if a ground problem comes up, it will overheat the wire, which will either burn it in half, or at least turn the white insulation dark. off the top of my head, two of the most common problems with these running rough, is either a dirty carburetor, or a leaking intake manifold. if it is an electrical problem, they usually show up with heat, and take 15 minutes plus to show up. please notice i did say usually. one thing about electronics, is there is no certainty.

[Ajmboy]

Good point XWrench3, that is high for battery voltage. Great info!

[XWrench3]

i have better than 30 years of working on these things. i am now diabled (back injury), so in a way, i guess this is my way of giving back. but i am happy to help when i can

[jfag5093]

That's odd, sounds like there is an open circuit somewhere. Do you have a wiring diagram?

Thanks for the help. I finally called a suzuki service dept. and told them what it was doing and they immediately told me it was the regular-rectifier. I put one on and it solved my problem.

[jfag5093]

17.68 volts is way to high. the first thing to check is the battery bolts. if they are even a bit loose, it can cause a high reading. if they are indeed tight, the voltage problem may very well be the rectifier/regulator. i believe on that model it is under the plastic behind the front rack, bolted to the frame. as far as it misfiring /running rough, that is most likely not a voltage problem. there may be a problem in the handlebar switch assembly that may be causing it, you may have a bad ground (by the way, aprox 70% of all motorcycle/atv electrical problems are a ground problem). if you had a bad ground in the right spot, it could be causing both problems. but that is not likely. that in no way means you should not check it out. on my machines, one of the first "modifications" i make is to run one wire, from the negative battery post, to the engine, and then on to the frame. i make this out of a very light gauge, white whire, so if a ground problem comes up, it will overheat the wire, which will either burn it in half, or at least turn the white insulation dark. off the top of my head, two of the most common problems with these running rough, is either a dirty carburetor, or a leaking intake manifold. if it is an electrical problem, they usually show up with heat, and take 15 minutes plus to show up. please notice i did say usually. one thing about electronics, is there is no certainty.

Thanks for the help. I finally called a suzuki service dept. and told them what it was doing and they immediately told me it was the regular-rectifier. I put one on and it solved my problem.

[Ajmboy]

Glad you solved your problem, looks like XWrench3 was on the money!