97 Polaris sportsman 500 runs about 10 sec then dies

[Danny Gardner]

Hello, Everyone first time here, I appreciate this opportunity, I have a 97 polaris sportsman 500 that I just acquired, been sitting awhile ,would not turn over with a new battery, replaced the starter, got it to turn over, but no fire, replaced the coil, cdi box, new spark plug, spark plug wire and boot, still no fire, So I changed out the stator, boom I have Fire, Carburetor was in bad shape ,so I installed a new carburetor, a new fuel pump and filter and all new hoses, and before I tried to start it I cleaned the fuel tank, well here we go, It started right up idled like a brand new one, Idled for about 10 seconds and died, fired right back up idled great and revved up great, but in 10 seconds it died, fired right back up, this time I held the throttle about half throttle, and it kept running, but when I let off it died, so I then adjusted the throttle cable from all the way tight to all the way loose, and vise versa, still the same thing, Please somebody help, cause I'm bout to give it the HAMMER TEST.   

[Danny Gardner]

?

[Frank Angerano]

Hahahaha the hammer test.  That’s a new one. So my guess is that the fuel in the bowl of the carburetor is being used up and then being starved for fuel hence the bike shutting down. So I would think the fuel delivery to the carburetor is restricted somehow.   I would make sure the fuel delivery from the tank/gas valve, through the pump is working correctly.  Take the fuel line off of the carb and aim it into a can of some sort, pull the spark plug wire ao the bike won’t start and crank the bike and see what kind of flow you have coming from fuel line. If it’s flowing good then that’s great. If not start working your way back. 

 A lot of times when you do all the cleaning of the carb and tank etc sometimes a piece of leftover junk in the tank can get into a jet, float pin etc.  it sucks but can happen.

You can also get a small fuel tank and connect it to the carburetor and let gravity feed the carb, start the bike up and see if it runs steady.  

[Danny Gardner]

What gets me though, is you can crank it, and before it has time to die, you can hold it steady at half throttle and it will run until next week, but when you let off it dies.

[Brian Haley]

Will it run continuously with the choke closed or is it the same thing? Also when it runs for those 10 seconds what is the idle speed and does it die out or shut off abruptly?

[Frank Angerano]

Is the new carburetor an oem or aftermarket? We seem to go through this a lot with oem versus cheap replicas.  They don’t work very well.   The oem carb as long as it’s only a dirty/clogged carb it’s nothing a good soaking and cleaning could not fix. Must be taken apart and properly cleaned. 

Is this something you can do? It’s not hard.

 

[wanrep]

2 things come to mind. 1) check the ETC in the throttle. Make sure there is a gap between the contacts at idle or you can just unplug the wires coming from it.

2) the idle mixture screw or the idle speed screw need adjusting.

[Danny Gardner]

Its an aftermarket, thought I would save a couple of bucks, your right, all the old one needs is a good soaking, and blowing out, I have been working on fixer uppers all my life, so there's no problem with me doing the work, I will let you Know how it turns out, Thanks

[Danny Gardner]

11 hours ago, Brian Haley said:

Will it run continuously with the choke closed or is it the same thing? Also when it runs for those 10 seconds what is the idle speed and does it die out or shut off abruptly?

Its the same thing with the choke either way, the Idle speed is normal it idles great, and revs perfect, but in 10 sec. it dies like you turn the key off

[Danny Gardner]

6 minutes ago, wanrep said:

2 things come to mind. 1) check the ETC in the throttle. Make sure there is a gap between the contacts at idle or you can just unplug the wires coming from it.

2) the idle mixture screw or the idle speed screw need adjusting.

I've checked the ETC, and its good, I also unplugged it and tried it, the idle speed screw I have adjusted, but I haven't checked the idle mixture screw, should that be at 2 1/2 out? 

[wanrep]

1 hour ago, Danny Gardner said:

I've checked the ETC, and its good, I also unplugged it and tried it, the idle speed screw I have adjusted, but I haven't checked the idle mixture screw, should that be at 2 1/2 out? 

2 1/2 out is a good starting point. It should idle at that setting.

[wanrep]

Does holding the override button in make any difference?

[Danny Gardner]

6 hours ago, wanrep said:

Does holding the override button in make any difference?

No it doesn't make any difference

[carguydave]

I still think it's running out of fuel. The fuel pump runs off of vacuum. If the baffle or spring in the pump is too stiff, it would give the symptoms you describe. I would hook up a gravity feed external fuel source and see if it will stay idling. The other thing that is a possibility is that the engine isn't producing enough vacuum. Try the external tank first, then we can go from there.

[carguydave]

Oh, one other thing, check that there isn't a small vacuum leak in the hose to the fuel pump and that the lines are routed correctly.

[Danny Gardner]

On 11/24/2018 at 12:13 AM, carguydave said:

Oh, one other thing, check that there isn't a small vacuum leak in the hose to the fuel pump and that the lines are routed correctly.

I found the Problem I did all the things you said, but still same results, so for some reason, I decided to take the new cdi off and put the old one back on,and boom that was my problem it runs like a champ now, Thanks guys for all your help I appreciate it.

[Maggie Hall]

no doubt, sounds like a gas issue or a vacuum line issue. 

[Danny Gardner]

 found the Problem I did all the things you said, but still same results, so for some reason, I decided to take the new cdi off and put the old one back on,and boom that was my problem it runs like a champ now, Thanks guys for all your help I appreciate it.

[carguydave]

Glad you found it.

[JacobSlabach]

On 11/20/2018 at 8:20 AM, wanrep said:

2 things come to mind. 1) check the ETC in the throttle. Make sure there is a gap between the contacts at idle or you can just unplug the wires coming from it.

2) the idle mixture screw or the idle speed screw need adjusting.

got a friend with an 02 sportsman that has this same issue with the ETC and he has never really figured it out...(he doesnt really care about the bike so he just keeps his thumb on the throttle when he wants it running- a pain for me to run tho since im not used to never coming to a complete idle..lol  could you expound on this more maybe?  what is the ETC? and what does it do?

On 11/20/2018 at 8:33 AM, Danny Gardner said:

I've checked the ETC, and its good, I also unplugged it and tried it, the idle speed screw I have adjusted, but I haven't checked the idle mixture screw, should that be at 2 1/2 out? 

oh never mind thats not the problem.

[wanrep]

[Frank Angerano]

@wanrep so that little son of a bi*** etc had me going nuts on one of my older Polaris bike projects.  I could not figure it out for the life of me. It was brought to my attention by a member @davefrombc on this site that the etc could be giving me trouble.  Backfiring spitting etc. anyway I removed the part all together and that bike ran like a champ.  I would have been looking for quite some time before I figured that out.  @davefrombc 👍

[wanrep]

Yep, been there too.  Most times it's not enough slack in the throttle cable that causes the problem.

The other thing that causes problems with spark is that rev limiter box.  You just unplug the black wire to eliminate that.

[Frank Angerano]

Yep that as well. The etc believe it or not was corroded and had moisture in the control.  The rev limiter was a hot mess.  Took the controls off and added a rip cord kill switch by passing both and the bike ran great.