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Hello, i have a polaris magnum 425, 96', and i have engine troubles.. It runs ok at idle and mid range, but will start to rev to top end and then die out.. The plug is white which means lean but when i take the air box off it runs fine ! I dont understand it.. I went throught the carb twice and it has stock jets, cleaned all and still same thing.. Any help would be appreciated.. Tried different fuel pump, no dice..
 

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i think there was a thread on here not too long ago with someone with about the same problem. the seat was smashing the intake boot shut. it is making black smoke at high rpm's?? strong spark?? you may want to adjust the valves(.006 for all four at tdc.) my expedition,same motor,was getting to where it wasn't wanting to rev(it wasn't cutting out like yours,just not revving) i adjusted the valves and runs like new.check the cam lobes as well, should be able to reuse the valve cover gasket
 

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Bad cam

Actually i pulled the valve cover the same night that i put this problem on the website and the intake lobe is worn badly.. I guess that the polaris magnum 425 had a problem with that, and there is an updated camshaft! Thanks for the reply though!! If anyone knows where i can get cheap camshaft and rockers that would be greatly appreciated..
 

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Actually i pulled the valve cover the same night that i put this problem on the website and the intake lobe is worn badly.. I guess that the polaris magnum 425 had a problem with that, and there is an updated camshaft! Thanks for the reply though!! If anyone knows where i can get cheap camshaft and rockers that would be greatly appreciated..
I have a used cam and rocker assembly if you still need it. I know this post was made in December. Thanks
 

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Actually i pulled the valve cover the same night that i put this problem on the website and the intake lobe is worn badly.. I guess that the polaris magnum 425 had a problem with that, and there is an updated camshaft! Thanks for the reply though!! If anyone knows where i can get cheap camshaft and rockers that would be greatly appreciated..
I have a used cam and rocker assembly if you still need it. I know this post was made in December. Thanks
i need a used cam and rocker for my 425 96 how mutch ? plz
 

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$125.00 for the camshaft and rocker arm assembly. Thanks
 

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hey guys, i am going through the same prob, but it gets alot better once its warmed up...cold it has no go..i have one through all the fuel system and was going to blame it on the fuel pump until i read this post...could the beginning of this issue be worse when its cold? mine is a 97 425 magnum..i have heard this was only and issue with early models..is mine old enough?
 

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hey guys, i am going through the same prob, but it gets alot better once its warmed up...cold it has no go..i have one through all the fuel system and was going to blame it on the fuel pump until i read this post...could the beginning of this issue be worse when its cold? mine is a 97 425 magnum..i have heard this was only and issue with early models..is mine old enough?
The 97 also had camshaft issues.
 

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were they also known for fuel pump issues? it still has great power, just starving when its cold...cams would do it all the time i would suppose.. when i take of with the motor cold it will have a great surge of power then it will kinda top itself out,kinda like its not getting enough gas, will pop occasionaly, but never does it after initial warm up...also i have notice the carb drips a little from the overflow tube...
 

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were they also known for fuel pump issues? it still has great power, just starving when its cold...cams would do it all the time i would suppose.. when i take of with the motor cold it will have a great surge of power then it will kinda top itself out,kinda like its not getting enough gas, will pop occasionaly, but never does it after initial warm up...also i have notice the carb drips a little from the overflow tube...
Its sounds like you may have fuel problems. The needle seat and jets may have some wear. Clean the carb and replace the jets if they don't have a good point on them. Check the diaphram in the top of the carb for dry rot also. I think the problem is the needle seat because it causes the engine to backfire, loss of power and it also causes too much fuel to get into the carb. Thanks
 

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thank you for your help, i have had problems finding any parts for this carb...i would much rather put a carb of a 500 on it, from what i read i would be happy..just wish i could buy everything i needed in one shot instead of having to track down parts...i am not even completely sure all that i would need
 

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thank you for your help, i have had problems finding any parts for this carb...i would much rather put a carb of a 500 on it, from what i read i would be happy..just wish i could buy everything i needed in one shot instead of having to track down parts...i am not even completely sure all that i would need
You can buy the needle seat at a Polaris dealer. They should have one in stock. I think they cost about $35.00 That is probably all you will need. You might can just clean your old carb and be back on the road. If the fuel sits very long it causes a gum deposit to build up in the carb in less than a month. Always use a fuel stablizer.
 
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