Hi Everyone, I have a 2000 Suzuki QuadRunner 500 that is having some issues running good consistently.

Sometimes it runs great, sometimes it sputters, boggs, and backfires.
The weird thing is that sometimes turning the ignition switch to have the lights on, it will run good sometimes, not all the time. I checked the ignition switch wiring and that seems ok.

Sometimes the fan kicks on and it runs better also.

I'm wondering if this is a rectifier issue or a short somewhere?
I try to trace all the wires and can't find anything loose...

Most people say carb, ignition, or bad gas, but if that was the issue I doubt the quad would run great after I yell at it...right? LOL

Literally it will run great, then next thing I know I'm sputtering and if I give gas it wants to die? I might have this issue for a couple minutes and sometimes longer, then it goes away and comes back.

I have changed the spark plug, has clean air filter, it's getting gas.

Any help or suggestions is greatly appreciated, thanks in advance.

 

Check how many volts the regulator is putting into the battery with engine running. If it goes over 15v the regulator is bad. When you switch lights or fan on, you may be getting the voltage down to a level the CDI can cope with.

 

Thanks Merryman. I will check this out tonight or Thursday. I'll post what I find. I appreciate the help.

 

merryman, I checked and it is spiking past 15 when it runs rough. Goes as high as 18, and when it drops below 15 in the 14's it runs perfect.

I found that this is common problem for Suzuki Voltage regulators, and the old OEM part was replaced. Suzuki confirmed the OEM part # and compatibility, but forgot to mention the wire harness plug design changed. So I have an opportunity to buy a used 1 but it has a different style connector. I am debating on cutting connector on my quad and the one on the regulator and hard wiring the 3 yellow wires. It is considerably cheaper but it does void the 1 yr. warranty on the used certified regulator. I was concerned not knowing how to properly match which yellow goes to which yellow, but the guy said it shouldn't matter since they all go to the stator. I'd save about

What do you think?

 

To be honest, all 3 phase regulators seem to be very similar except for the wiring plug, OK some have 6 wires, some 5 but the 6 wire type just have two positives for some reason. I think the three yellows can be wired any way round.

We only started selling/repairing Suzukis about 10 years ago, so haven't any knowledge about the pre Vinson 500s, but non genuine regulators with the correct fitting for your harness should be available. I would go for cheap Chinese if you can find one with the correct plug. Arrowhead and Bronco seem to sell non genuine regulators for nearly every model.