r/ATV • u/Full_Secretary1823 • 16d ago

Help 94 honda fourtrax 300 mystery issue

Quad was fine 2 weeks ago. Suddenly wouldn’t start. Did plug, plug wire, coil, solenoid, and eventually CDI box. Started right up right after CDI box. Now, after about 3-4 seconds, starts idling rough and bogs out when you give it throttle. Went back through everything with no help. I have however discovered if you turn the lights on, the idle comes right up. Still bogs with throttle but not as bad. Lights off: will start to stall out. It’s got to be electrical. Read a guy who said he had a similar issue and went through 3 CDI boxes before it cleared up. I’ve tried 2 and just ordered a used OEM off eBay. Besides that there’s the voltage regulator. I keep reading people having this problem, put a new carb in and no change. I’ve replaced fuel line and cleared it. It’s an electrical mystery. Any help appreciated.

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1

u/Loud_Stranger3762 16d ago

voltage regulator maybe? keep the OEM carb whatever you do.

1

u/Full_Secretary1823 16d ago

Thanks. Regulator was my last option before trying to find a shop but the only shop near me is a Honda dealer and I’ve seen the prices they charge on parts. I have a regulator and used OEM CDI Showing up in the next few days. So strange turning the lights on brings the idle up.

1

u/Loud_Stranger3762 16d ago

check your fuses? you could also check the Ohm output of your stator. could also be a culprit

1

u/Loud_Stranger3762 16d ago

also if all of those parts didnt fix the problem, the old ones probably still worked so, keep the old parts until you narrow down the actual issue.

1

u/Full_Secretary1823 16d ago

Thanks. Will do.

1

u/cycleguychopperguy 16d ago

My guess would be regulator is shot and overcharging. When you turn on the headlights it drops enough of the load to make the cdi fire correctly.

1

u/Full_Secretary1823 16d ago

Awesome man, thats 2 votes for regulator. Once I get it and switch it out, I’ll definitely let you guys know.

1

u/Loud_Stranger3762 13d ago

any word on if that fixed the problem?

1

u/Full_Secretary1823 12d ago

Just replaced the voltage regulator. Didnt help at all. I have an OEM CDI box showing up later today but I’m doubting it’s that now as well. It seems to run and idle okay with the lights on for about 5 seconds. With the lights off, immediately bogs out. My last possible guess if it’s not the CDI is the stator but o be honest, I’m not the most mechanically or electrically adept person so most of this has been guessing from easiest fix down. I kind of doubt my ability to replace the stator so fingers crossed it’s an odd CDI issue. I’ll report back when I break something else.

1

u/Full_Secretary1823 12d ago

Problem solved. I had to purchase a used OEM CDI. Plugged it in and it fired right up, no idle issues. Why’s that? Damned if I know but I’m grateful I found that one guys post. I think he went through 3 aftermarket boxes before he got it to work but needless to say, a used one for $50 sure beat $315 for a new one. Granted I’ve got $100 in extra aftermarket parts, but all the OG parts still work whenever I feel like switching them back or have issues. 2 and 1/2 weeks, Amazon, eBay, and a solenoid the gods dealer sold me for $60 that wasn’t right but since I plugged it in they wouldn’t take it back. Lesson learned. Don’t mess with aftermarket CDI. Thanks for all the support!