I bought my son a used 90cc Fushin quad and replaced the dead PXT5L-BS battery with a new 5LB battery and now all it does is blow fuses. Even while the bike is off no key in the ignition as soon as the fuse touches the connectors the fuse blows, but it ran fine yesterday with the dead battery that I had to jump to start. The dead battery would always start once or twice own its own after a jump but it never blew a fuse. Should I go down to a 4LB battery?

Where can I find an owners/service manual?

Also there was a recall last year for Fushin quads I tried contacting them but no contacts are working. How can I find out if my quad is part of the recall?

Thanks in advance, any info is greatly appreciated.

 

Start disconnecting connectors in your wiring harness. This way you can isolate things that could be shorting the battery to ground. Eventually you will find some connector that when disconnected will stop the fuse from blowing. By looking at what connector you disconnected you will get a major clue as to what is shorted.

Start with the voltage regulator connector. This is the most common high current fault path that does not also involve having the ignition switch turned on.

If you still have a short after all the connectors have been disconnected then we'll have to try something different. But I bet the 'unplug connector' route will pay off.

 

Ok so I soldered all crimped connections and covered with black tape. Then began testing connections, fuses kept blown instantly upon contact, until I disconnected the left switch assembly. When disconnected I was able to install a fuse without it blowing. As soon as the Left Switch Assembly was connected the fuse blew. It looks brand new and is clean inside and out is it common for the LSA to go bad? Also what size fuse should be used a 15 or 20 amp fuse?.

 

I've never had one of these go bad, but I've had lots of other chinese switches go bad.

Switched battery power goes to this switch, then on to other things. It is possible that the short is on the far side of the switch. Eliminate this possibility by turning off the headlights and making sure the starter button is not engaged. Does the fuse still blow in this configuration?

If it does then the switch assembly is bad

 

So after messing with the LSA the fuse wasn't blowing today, that was till I noticed I didn't have the ignition hooked up. I plugged in the ignition and messed with the LSA and still no blown fuse. Then I turned the key to the OFF position and pow the fuse lit up like a xmas tree. The ignition is brand new I just bought it on 10/9/2010. I asked for an ignition for a 90cc Chinese atv and the dealer said that ignition was the correct one. I'm going to try exchange it tomorrow but isn't an ignition just an ignition or could it just be faulty?

 

What didn't you mention this before? This is a really important piece of info. On your first post you claimed you changed only the battery and it started blowing fuses. Are there any other recent changes you need to tell us about?

It is possible that your ignition switch is wired incorrectly. Most chinese ignition switches have four wires:

1) Fused Battery Power (from battery plus terminal through fuse)
2) Switched fused battery power (power to all 12 volt stuff only when ignition switch is on)
3) Ground
4) Kill switch (open when ignition is on - shorted to ground when ignition is off)

Note that it is possible to wire the switch incorrectly so that battery power is shorted to ground with the switch, which would instantly blow the fuse.

Use a meter to figure out which two wires on the switch are connected when the ignition is on. What are the colors of these wires in the main wiring harness. Then verify that the other two wires are connected when the ignition is off. What are these wire colors in the main harness?

BTW fuse should be in the range of 7 to 10 amps. 15 to 20 amps is too high.

 

I didn't mention it because after I installed the new ignition I was still able to start and run the quad with the old battery only after jumping the battery. Its only after I bought a new battery charger and charged my battery for 4 hours and it was still completely dead that I decided to get a new battery. Then as soon as I hooked up the new battery the fuses started blowing. So the thinking was that either the new battery is too big a 5lb instead of a 4lb, or the fuse was too small. So after trying 15 & 20amp fuses with both the 5lb and 4lb batteries the thoughts went to other things other than the ignition because the ignition was new right out of the package. My brother was over yesterday so I had him keep an eye on the fuse as I tested everything and as I went through everything nothing was blowing the fuse till I turned the ignition off. So after we noticed that we tested it again and sure enough that was it. I'm not 100% of the colors because I'm not home to look at the connector but it does have 4 wires Red/Black/Red&Blue/not sure of the 4th it may be white. After work I'll exchange the ignition then test it out and see if I can get this going.

 

Because the ignition switch worked at one time it cannot be wired wrong. It may have broken up inside which allows the 12 volts to get shorted to ground with the switch in the off position (bad in other words), but there is another posibility:

When your ignition switch is in the off position the kill switch connection is shorted to ground. This is what kills the spark and stops the engine. The kill switch wire also goes up to your handle bar switch which has another kill switch in it as well. This one also works by shorting the kill switch wire to ground. The handlebar switch assembly also contains fused 12 volts to power the lights. Suppose there is a short in the handlebar switch assembly that connects 12 volts to the kill switch wire. Then the fuse will blow if the ignition is turned off or the handle bar kill switch is activated. This is because the kill switch wire gets grounded when you do this, and it is also shorted to 12 volts which blows the fuse.

If you disconnect the handle bar switch connector, does the fuse blow when the ignition switch is turned off? If so, that would point to the handlebar switch as the culprit.

 

OK the ignition is fine brought it back to the dealer to test it worked fine so I bought a new Left Switch Assembly. Just tested it out hooked up the battery then put in a 20amp fuse & it didn't blow, plugged in the ignition while key is in the off position no fuse pop, turned the key to on and no fuse pop. Plugged in the BRAND NEW LSA and pow fuse blew like a flash bulb. Messed around with the LSA shutoff the lights hit the kill switch. Plugged in a new fuse 15 AMP and it didn't blow, turned the headlights on and the fuse blew but this time it didn't blow instantly it gradually turned red then blew took about 3seconds rather than instantly. Now what? I'm gonna throw this thing in a river pretty soon.

 

Since your problem is not repeatable you don't have a solid short. And since it seems to be sort of random I'm wondering if the problem isn't elsewhere, and it is you tugging on wires at at the LSA that is causing the problem to come and go.

I'm assuming your LSA does three functions:
1) Lights
2) Handlebar Kill switch
3) Start button
Am I right about that assumption?

Disconnect the LSA. Leave it disconnected for now. Use a meter to identify which two pins get shorted together when you push the start button on both your LSA's. Do they agree? Then manually start up the quad by shorting the two wires together in the wiring harness that would normally be hooked up to the switch start button. Use a pair of pliers, or whatever. When the quad starts remove the manual short. Does the quad run normally? Does the fuse blow? Wiggle wires around. Does the fuse blow now? The headlights won't work of course, but does everything else work? Brake light? Battery charging system? Just looking for clues.... Often seemingly different problems are related, and if one avenue gets tough finding and approaching the other problem leads to a solution to both problems though an easier path.

Do you have enough plastic off so that you can see all the connectors? That last fuse blowing where it glowed for three seconds indicates that you were drawing 20 amps or so. There is nothing on the quad that draws that kind of current, so it has to be a short to ground. And if it was a solid short the fuse would blow instantly. Thus I suspect the short to ground was through wire just brushing against ground, and there must have been sparking there. You may want to try doing your tests in a darkened environment, with the fuse masked off with tape so you can see flashes coming from elsewhere.