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Discussion Starter #1 (Edited)
Hi all,
Could sure use some help. I purchased a non running 1994 Polaris 300 2x4 W947530. Rebuilt the carb and got it going. Was zipping around the yard no problem and then started fine tune the carb and it started to bog, surge, and bang.
Took apart the carb and recleaned it 2 more times and still have the problem. It will low idle all day with no problem but try to rev it and bog and surge starts up again.
The weird thing is that every once in a while it will rev fine so i will take it for a spin and in 100 yards it bogs down again.
I am out of ideas.

Here's what I've done so far.
Rebuilt and cleaned carb. Float arms parallel per spec. All new parts from kit installed.
New non-ethanol premium gas premixed at 75 to 1
Oil pump works with amsoil intercepter oil (yes i am using more oil than needed just to be safe)
New battery
New starter and bendix
Etc works properly but has been disconnected for trouble shooting
Exhaust port is clear
*New fuel line and fuel filter installed

Any ideas appreciated.

Thx
Pigseye
 

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Did you check the plug and air filter. Might I suggest going back to the way the carb was set before you fooled with it. If it ran before you tried to tune it go back to what it was and leave well enough alone for now. If you didn't modify anything with the engine, pipe, or air box there really isn't much tuning you can do without possibly causing yourself headaches. Or, buy a new plug and do a plug chop to see if you are too rich or too lean. A plug chop is your best friend when tuning.
 

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You might also try a leak down test to make sure the crankshaft seals are good. If the seals were leaking it could lean out your fuel mixture. I dunno - just a thought...

Also check the rubber intake for cracks (between carb and engine).
 

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Discussion Starter #4
Hi Frit91,
There is a new spark plug properly gapped and air filter is good. I'll add that to my list of things I've tried.

I did reset the carb back to when it was running and it still wouldn't run properly consistently. I've also tried adjusting the air screw from closed to open 2 1/2 turns. Very extreme but unfortunately neither setting makes any difference on how the engine runs. Like I said in my original write up, on some occasions it will just run really good and then stop after a few minutes. So I don't know if a plug chop will be helpful at this point. Something is intermittently really wrong and I don't think that the lean/rich fuel setting would create that behavior. It is just bizarre.

Hi Diverod,
Good idea to check the rubber intake and/or perform a leakdown test. I'll try that later this week.

Appreciate the feedback!
Thanks,
Pigseye
 

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i have a 1997 sportsman 400 and it turns over but will not start. i have replaced the starter and battery and checked all electrical connections. i have a gas leak in bottom of tank, has a small problem getting gas to carburetor. it doesn't really get gas. i replaced the oil pump casing as well because the screws stripped the threads out ... any help. will try anything
 

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1997 polaris sportsman 400 problems

i have a 1997 sportsman 400 and it turns over but will not start. i have replaced the starter and battery and checked all electrical connections. i have a gas leak in bottom of tank, has a small problem getting gas to carburetor. i replaced the oil pump casing as well because the screws stripped the threads out ... any help. will try anything
 

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Hi Frit91,
There is a new spark plug properly gapped and air filter is good. I'll add that to my list of things I've tried.

I did reset the carb back to when it was running and it still wouldn't run properly consistently. I've also tried adjusting the air screw from closed to open 2 1/2 turns. Very extreme but unfortunately neither setting makes any difference on how the engine runs. Like I said in my original write up, on some occasions it will just run really good and then stop after a few minutes. So I don't know if a plug chop will be helpful at this point. Something is intermittently really wrong and I don't think that the lean/rich fuel setting would create that behavior. It is just bizarre.

Hi Diverod,
Good idea to check the rubber intake and/or perform a leakdown test. I'll try that later this week.

Appreciate the feedback!
Thanks,
Pigseye
Sounds to me like the Fuel inlet at the float needle has some kind of obstruction in it! And if it gets worse once it warms up there can also be a Vacuum leak at the intake! And it don.t change at all when you move the fuel or air screws ?? You better take a deeper look into doing that carburetor right!
 

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Sounds to me like the Fuel inlet at the float needle has some kind of obstruction in it! And if it gets worse once it warms up there can also be a Vacuum leak at the intake! And it don.t change at all when you move the fuel or air screws ?? You better take a deeper look into doing that carburetor right!
After 4 years I would presume it's been fixed or gotten rid of
 
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