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Posted

Howdy y'all, I'm trying to fix a neighbors 2015 Brute Force 300. Came in with hard to start and won't idle except on choke issue. I pulled the carb and found the pilot jet as well as the emulsion tube partially clogged. Cleaned up everything, put it back together, still having issues...  It will start right up on choke and will also start off choke if you give it just a touch of throttle but it absolutely will not idle unless it's choked just a touch. Also, excuse my ignorance but I'm assuming the "dial" thingy attached to the carb that turns in and out is for setting idle?? 

  • Like 2
Posted

Not sure about the dial thingy but it should have a knurled thumbscrew on the side somewhere to adjust the ilde speed, and the idle mixture screw is at the front underneath and hidden up a tube.

Did you check the rubber inlet manifold wasn't split, or that it doesn't have an air leak somewhere ? Tight valves can make them hard to start and not idle well too.

  • Like 2
Posted

The black plastic knob attached to a cable is for adjusting the idle speed, not sure about a dial either unless that is whaat you are calling it. It sounds like there is still gunk or trash in your idle circuit jet or maybe the emulsion tube ,did you take that out and clean it. There is also a hidden jet down in a hole thats easy to miss.

  • Like 1
Posted

I appreciate the responses y'all, yes, the plastic thumb screw dial thingy is what y'all mentioned, it is to adjust idle. I wasn't sure what to call it, lol. Anyhow, I didn't see any splits or tears on the intake boot and also double checked the connection was sealed. I even sprayed a quick burst of carb cleaner on the connections and it didn't speed up the engine. When I had it apart I did remove every jet as well as the emulsion tube, the emulsion tube and the pilot jet were both partially clogged and I cleaned everything. As far as the mixture screw, apparently someone has messed with it at some point because the cap has been removed, is there a special tool required to adjust that and what is a good starting point as far as setting it? As far as I know there haven't been any mods to the machine but I will be talking to the owner this evening.

Posted

Well..... I don't know what I did, or didn't do the first time but after taking it back apart and going through it again, it starts right up without even choking it and purrs like a kitten. Thanks y'all. I have another question as far as coolant, I'll ask but please let me know if I need to start another thread.  The coolant reservoir is reading on the Low mark, do I add coolant to the reservoir or in the radiator cap directly? Again, excuse my ignorance but this is my first time on a water cooled Quad...

  • Like 1
Posted

Good for you. Perseverance always wins. Giving up never does.

You normally just check and top up the reservoir bottle. If you suspect it's using water you take the radiator cap off when the engine's cold, you top the radiator right to the very top, then you put the cap back on. As the engine heats the level in the overflow bottle will go up, and when it cools the level will drop. It's a good idea to familiarise yourself where the two levels are and always check they are moving from cold to hot. If the radiator gets a small hole or blown gasket the level in the overflow bottle will probably change with use, but sometimes the radiator sucks air in instead of drawing water from the bottle, then the level stops changing from cold to hot. Glancing at the level before starting, then again after it's warmed up, is a good way to spot any problems at an early stage.

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