Hey all!
been digin for awhile but no luck,
so here's the lowdown. I have a 99 sportsman 500 with power issues. tried some fuel additive to clean it out but no luck. The machine has a new camshaft and rockers with 22 hours on them. clutches have also just been rebuilt and work beautifully.The fuel is fresh, i keep having to drain it out, haha. Oil change was also with the new camshaft so that has 22 hours on it. Coolant flushed real good and fresh stuff a few weeks ago as well. temp dummy light taken off and tested, pretty sure it comes on at about 210 F? if thats correct. the light for the temp sensor works to and has not lit up during any of the testrides. all looks well inside the carb, the float needle has a ring around the tip where it has been sealing off the fuel, but no damage to the cone shape that the naked eye can see. where the needle sits, there is some gold showing from wear on the inner diameter, but nothing to crazy.

Carb was taken off, apart and cleaned. for the first five or ten minutes on the clean carb, it had all the power in the world and sounded amazing, only now the power just isn't there anymore. every time i take the carb off there is fuel on the intake boot of the engine, so maybe to much fuel at WOT? so i took the main jet needle in one notch and cleaned the carb once again. this needle setting made a noticeable difference, i didn't have to baby the throttle to get it to take off and haul butt. Of course i only have a few minutes of fun and back to no power. runing with full or low power, there is no cutting out or sputtering, only a little when the EBS kicks in, but a higher idle helps remedy this. on a low idle, it WILL pop pretty good on deceleration.

any questions or ideas thanks in advance!

 

welcome to the forum. take out the sparkplug and see if it's wet. if it is wet after your little test ride then it's getting way too much gas and maybe your float isn't working. the needle and seat may need replacing as there shouldn't really be any ring on the needle.

 

Replace the needle and seat! There should be no"visible" mark,rings,etc. The "gold color" you're talking about is brass and it's a very soft metal.

 

Thanks a bunch! The plug wasn't wet, just some carbon buildup on the tip, which I cleaned off yesterday and already a thin film.
Looks like I'll be Getin a carb kit!
Is there any way to tune the pilot air screw when I put the new one in?

 

You have to drill out the block off plug to get to the pilot mixture screw,but if it has been running ok previously I wouldn't tamper with it. Only if you've made modifications to the exhaust,etc and after the carb kit is installed and it doesn't idle properly,then would be the only time I'd try adjusting this screw. Plus you need a very small screwdriver or a carb adjusting tool to adjust the pilot screw while it's running.

 

Moose kit came today and is gona be installed this weekend. The pilot screw is exposed, plug must've been taken out a few years back when my dads buddy was workin on the carb for us. It idles fine I'd just like to be able to have it idle low so I can shift easier, while also preventing sputtering when I get off the gas and the EBS kicks in.

Also, the starter likes to hang on to the flywheel for a little to long. Then one it lets go of the flywheel and idles I'm pretty sure the starter gear assembly is what's rattling (this is constant when machine runs). If there's anything to rebuild on it or rig up to help stop rattle that anybody knows of.

Thanks for the help!

 

Don't adjust the pilot(fuel/air) screw to get it to "idle" lower. This is a mixture screw only to make it idle smoothly on the fuel air mixture. Just use the idle adjust screw to alter the idle.#31 is the idle adjust screw. Don't tamper with #30 unless it needs it. Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse

 

500 engines were really the main ones to have the bendix(gear shaft) hang up while starting. You can "blip" the throttle when it starts which helps kick the bendix back quicker and less wear and tear. If it gets to where it's constant,easier just to replace it rather than trying to clean and grease it,replace the spring,etc as they are cheap.http://www.dbelectrical.com/p-5731-n...6191-2962.aspx Plus the starter bushing inside the recoil cover and inside by the starter can wear over the years and cause problems along with causing the "rattling" noise from the bendix. Item #9 (qty of 2) http://www.cyclepartswarehouse.com/f...1999&fveh=5486

 

Alright, moose carb kit was installed today. Pilot screw set to 2 5/8 as clymer book calls for.
Same problem as before now. No power. After a few laps around the yard I pulled the plug and there's no door ring around the base threads, the plug turned a little more light gold color, maybe to lean on fuel now?

I would've torn into the bendix but now looks like I might have a fuel pump or float height adjustment to do?

Thanks for the help

 

Float arm should should be parallel with the carb body when held upside down on this model(13mm/.051). Also if you have any broken studs on the air box(bad on this model)it can leak air under the lid causing lean running conditions.This model was bad about the carb partially pulling out of the intake boot and can suck air,plus check the intake boot for any cracks. I'd recheck the valve settings too .006 intake and exhaust,even if it's a new cam and just has a few hrs on it. 2 5/8 turns out is the "normal" setting on the pilot screw,but best to fine tune it from this base setting while running at an idle.