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Discussion Starter #1
Hello all. I'm not only new to this forum, but new to all forums. I guess we'll see if I can figure out how to navigate these things. You know the old saying, "Old dogs, new tricks....?"

Any way hello and HELP!!

I recently bought a used 2000 Polaris Xplorer 250 cc 2 stroke 4WD. It ran pretty good for a a few weeks. It even needed a battery and I was pull starting it until I got around to getting a new battery. Coincidentally, when I finally got the new battery, that is when the problem started. I'll describe what it does and hope that its a text book symptom for an easily diagnosed problem from one of you that is far more knowledgeable than me about these things.

The electric start and battery are fine now. I'll crank and crank and crank and crank and crank and crank and nothing happens. Then after maybe 3 minutes of cranking off and on, it will rumble or sputter just a bit and then go back to cranking and cranking again. Then after another minute or so it will faintly rumble or sputter again. If I keep cranking it, the rumbling or sputtering will get a bit more frequent and eventually I can play with the throttle a bit and get it to catch on, barely. When it does start to catch on, it starts to run, but I must keep playing with the throttle to try and keep it going and it is barely going. Almost sounds flooded, but I'm very good about not giving it any throttle until it starts the faint sputtering so I really don't thing its flooding.

I've had one local amateur repairman, tell me he heard of these thing's oil injection system giving too much oil and suggested that is what was making it hard to start and that I should disconnect it and just premix.

I called my local dealer and they thought the compression was low. I just bought a compression tester and checked it tonight and got a reading of 85. The dealer said it was supposed to be around 100 I think.

Whew! Sorry for the long winded story, but I wanted to try and explain what was happening well.

Thank you in advance for any help in this matter.
 

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Welcome to the board!:med:
 

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Does the machine have ETC (electronic throttle control)?? It should say on the thumb throttle assembly.
 

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Are you giving it any gas while its cranking? Lots of things it could be on an older 2 stroke, I picked up a 400 2 stroke scrambler so I know the headaches.
 

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Discussion Starter #7
As far as giving it gas, I was taught to give it a couple pumps of gas on a cold engine and then none while cranking so that is what I have been doing. Every once in a while, while cranking, due to frustration, I would break that rule and give it some, but until it started to try and catch about 4 minutes into the cranking it was a useless effort. Once it started to sputter and rumble a bit every once in a while, giving it the gas would help it to catch on and and try to run barely as I mentioned it sounded flooded but since I was really giving any gas it should not be.
 

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Discussion Starter #8
What do you think about that compression reading? Too low?

In my younger days, I had plenty of 2 stroke dirt bikes and learned that those engines were pretty simple. At least back in the 70's. Fuel, spark and compression and it would run.
 

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Just a quick check you can do is pop the lid off that throttle assembly and make sure the contacts inside the throttle aren't touching while the throttle is NOT being pressed in. There should be about an 1/8" to 1/4" gap in between the metal contacts. Change in weather might call for carb adjustments or changing the jet. Does it have a fuel filter on it? Is it getting fuel? Carb clean?
 

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Im not sure on the compression it should have. You might search the forums specifically for that. "Buddy_1" seems to have good knowledge on the machines.
 

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Couple things. First, the carbs on these don't work like cars. When you squeeze the throttle lever it doesn't pump any fuel at all. They don't have an accelerator pump like an old Holly. Second, to do a proper compression test it needs to be wide open throttle while cranking and no more than 3 compression strokes to get top reading. Needs to be at least 100psi to run. Third, the amateur mechanic you talked to doesn't know what he's talking about.

Does it still start easy with the pull start? OR was it hard to start that way before? How does it idle and run once started?

First things I would do is replace the spark plug, clean the carb thoroughly, and make sure everything in it is set to factory specs, and check the ETC.

They are still the same simple thing they were in the 70's so don't get discouraged.
 

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Discussion Starter #12
I'll check those contacts. I'm not sure if it has fuel filter, but I'll check. It must be getting fuel as eventually it does run usually, no? Also, when I disconnect fuel line from top of carburetor fuel flows well so fuel is getting to carburetor. Carburetor is definitely clean. Cleaned it twice.

As I mentioned before, I'm new to forums in general. Can you tell me how to reach out to Buddy_1 specifically without hoping he reads my dilemma coincidentally?
 

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Discussion Starter #13
Wow, that info about the Holley carb makes me feel stupid. All my life I assumed it was putting fuel in every time you grabbed throttle. I wonder why they taught me that back then???

I definately did not do my compression test properly. I'll redo. I used no throttle and cranked it for about 10 seconds. Apparently I had about 50 compression strokes.

If I redo compression test and only get about 85 again, is it safe to say it needs piston rings and that may be my problem?

I'll change plug again, but I'm sure carb is clean, but not sure about factory specs. You're talking about the 2 screws on carb correct? Idle and fuel air mixture?
 

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Discussion Starter #14
Oops. Forgot to answer your other questions.

No, it does not start easy with the pull any more either so electric start or pull seems to be irrelevant. It must have been a coincidence that it started easy before I got a new battery. That means this problem just developed.

It idles and runs good once finally started, but I haven't got it to start at all lately. That's how it acted when the problem first started.
 

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Discussion Starter #15
Oh, I just remembered that once it did start, when it started, it would restart pretty easily as well as long as it didn't sit real long.
 

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If it runs good then it almost has to be a simple fix. How did the ETC look? What did compression test reveal using ridinagain's method?
 

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Discussion Starter #17
The ETC looked good, about an 1/8" gap. Confused though. Those contacts don't ever touch? When I had it opened, I gave it throttle and the stuff moves but contacts never touched.

Just redid compression test per ridinagain's method and only got 57. Ouch. I need piston rings. Does this agree with the symptoms I'm having?

Again, new to forums. Does everyone I'm dialoguing with see my replies, or is impolite to not answer everyone's help individually?
 

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The ETC looked good, about an 1/8" gap. Confused though. Those contacts don't ever touch? When I had it opened, I gave it throttle and the stuff moves but contacts never touched.

Just redid compression test per ridinagain's method and only got 57. Ouch. I need piston rings. Does this agree with the symptoms I'm having?

Again, new to forums. Does everyone I'm dialoguing with see my replies, or is impolite to not answer everyone's help individually?
Papa that is correct. The ETC will always maintain that airgap. It is a safety feature that should it get stretched or snap etc it will close the airgap and kill the motor. It will not start at all with the gap closed.

For the forum question, anyone viewing your thread will see your replies. Anyone that's talking in here will get an update that your or someone has posted/responded per their own configured settings. Some like instant updates, others prefer daily and some weekly.

Hope that helps.
 

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Discussion Starter #19
Thanks, redid compression test again using pull start rather than electric start and got 93. That's better, eh?

Just got off phone with dealer who told me to use pull instead of electric for compression test. He thinks its a vacuum problem, leaking fuel and flooding per se.
 
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