Brought in an 06 Predator 50 for tune up because it had been sitting and was hard starting. Prior to tune up I was able to kick it and get it to start after many attempts and took a long time to get it to warm up but seemed to run fine once warmed up.

Drained the tank, removed and disassembled the carb and cleaned thoroughly and blew out everything, installed new plug, added inline fuel filter, cleaned air filter, and put it all back together. Starts up easy now but it's now doing something I've never seen before... it runs great from mid-throttle to WOT with choke on but with choke off it bogs out and dies within a few seconds at WOT. Idles great with choke off but won't idle with choke on.

With choke turned off and airbox removed I am able to keep it running ok at higher RPM if I cover about half of the carb inlet with my hand... Almost acting like main jet is plugged and is going too lean and dying but the carb and jets are nice and clean. I've never dealt with such a temperamental little carburetor in my life.

Thanks in advance for any suggestions on this issue! I'll likely check compression tonight as well as disassemble the carb again to verify nothing made its way into the main jet.

 

Check that tank vent isn't kinked and is open.You can even pull the fuel cap to test. Pull the fuel line from the carb,turn the fuel valve to on and reserve position to see if both are flowing good or if it's possible one position might be clogged.If this checks out,recheck the carb main jet and needle nozzle.
Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse Not a fan of just cleaning carbs,but installing carb kits especially on machines that have been sitting up.2005 2006 Polaris Predator 50 Carb Carburetor Repair Kit 03 418 | eBay Easy way to crank these machines when cold also is to block off the air intake duct with your thumb. Make cold starts easy. Once warm they can crank right back up.Plus as you say,check compression,plus crank seals leaking over time can be another problem. One member had the same problem,found a leaking seal behind the stator.

 

I did check flow to the carb and seems to be fine. I also ensured the tank vent hose was open and venting freely then ran with gas cap removed and no difference.

The only variable for me that I am unsure of is if the choke plunger/mechanism in the carb can fail in a way to cause this symptom. I was going to check cylinder compression just for added measure but I doubt that this is contributing to the issue since I can get it to idle and rev up just fine as long as I am adjusting the choke...

Thanks for the reply!

 

If you have to adjust the choke to get it to run right,you still have a problem in the main circuit,whether it's a plugged up jet,jet nozzle stopped up,float needle sticking or even the small opening in the bottom of the float bowl that has to be clear and open that many over look so the choke circuit operates properly.That's why I pulled everything out of the carbs,soaked them good in Berrymans and made sure all passages were clear and open.Then they got new parts.You shouldn't have to go into a carb more than once.You can at least eliminate the carb as the problem and move on to other areas.

 

Not 100% sure what it was but I did pull the carb back apart, removed slide, needle, jets, etc and sprayed all the holes with some Berryman's carb cleaner and reassembled. Starts and runs perfect!

Ashamed to admit it but the first time I cleaned the carb I was out of carb cleaner and improvised with brakekleen so my guess is that one of the holes had some grime in there that the brakekleen wasn't able to dissolve. Moral of the story - don't improvise. Do it right the first time and save the headache.

Thanks for the help!