# Troubleshooting help With Starting



## JoshNate223

New to the forum just wanted some help with figuring out why my 2001 Polaris trailblazer 250 ( two stroke) won't start

It's got spark (gapped at .030)
It has compression based on just doing a finger test.
New starter just installed
The carb is fairly clean, I'm not 100% sure that is getting gas.... Put even when spraying starter fluid into the carb it doesn't start. 

Any thoughts appreciated


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## Polaris425

Sounds like the carbs might just need to be pulled & cleaned again. What about the plugs? How old are they? I know you said its getting spark, but if they are old and fouled it might not be enough.


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## brute for mud

The finger test is not accurate enough to tell if there is enough compression try spraying some starting fluid in the cylinder to see if it pops off or not


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## joshwyle

i had a polaris trailblazer not to long ago with the same issue. it ended up being the compression. the rings wer stuck in the piston. did a top end rebuild and it ran great till the day i sold it. think i got kit from dennis kirk for less than $150 and a service manual to. wasnt to bad. did it with the motor still in. but that my guess


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## Guest

If you have finger compression it is enough to start esp.with starting fluid. May not run good or stay running but definitely will hit. Carbs are not likely b/c spraying starting fluid will bypass carbs. Therefore not a fuel problem. That leaves us with bad plugs, bad valves or bad timing. Is trailblazer a 2 or 4 stroke. If 2 than it does not have valves. If I was a betting man I would say timing.


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## Polaris425

^^^ he said 2stroke somewhere in his OP.


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## Guest

Thanks polaris! I see it now. If plugs are good (replace if you haven't) you probably sheared woodruff key.


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## JoshNate223

I did a compression test, read 30PSI. I'm ordering a top end rebuild kit as soon as I get the cylinder off and figure out what bore size I need to order. 

I know for sure the carb is getting gas now too

Thanks josh^ that's what I'm doing. Found a rebuild kit for 100 bucks on Dennis Kirk, sounds good to me.
https://www.denniskirk.com/top-end-rebuild-kit.p1311102.prd/131110S.sku



It's got a new spark plug in it, which is gapped at .030

I can see that it's (the piston in the cylinder) not sealed all the way on one side so at first I was thinking of just getting new piston rings, but then thought I would just do it the right way and order a whole top end rebuild kit considering I would need to order new gaskets anyway. 

I'll keep updates posted, thanks guys. 

And I am planning in just leaving the motor in the frame while I rebuild in the top same as josh^^ was talking about


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## Guest

Sorry if I steered you wrong. Is the blazer new to you or did you just go out one day and it wouldn't crank? Just asking b/c 30 psi is low low.


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## JoshNate223

No man I don't think you steered me wrong at all..... I was gettin ready to write another post.

I'm thinking 30 Psi would be enough for the motor to kindof sputter and try to start a little bit spraying starter fluid in the carb..... But it didn't. It wouldn't surprise me at all if its the timing or the woodruff key. And that's why it didn't even try to start a little bit.

I bought it not running a week ago for a few hundred bucks expecting carb problems. I wanted to bring a compression tester with me when I bought it but didn't have access to one at the time.

It's my first four wheeler (I own a number of four stroke dirt bikes and have been surrounded by four wheelers for as long as I can remember). And if it does come down to timing I don't know how to adjust it. The woodruff key I bet I could do, hard to tell till I get into the motor deeper and see it.


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## Guest

well 30 psi is really low. I believe it should be 125-135. Below 100 and they'll run but... are you sure your gauge is good. Do a wet test by pouring some oil in the cylinder (enough to cover piston). This will temporarily seal the rings. Then immediately do a compression test. If rings are bad compression will rise. If you sheared a key pull the flywheel and replace the key-That's it! 

when doing comp test you need to have throttle wide open and don't stop until gauge stops moving. If you didn't have throttle wide open an didn't keep turning motor over until pressure stops rising you will most definitely have a false reading. Let me know


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## JoshNate223

The throttle was wide open during the compression test. I would do a wet test but I already have the whole top of the block pulled apart and the piston off and all. Appears that the piston and piston rings itself could very well be the problem.

The piston is scraped and rings are flush with the piston on one side....
















The other side isn't so bad^

I'm gunna take the cylinder to be measured for bore size and see if they think I should get it re-finished if its too scraped up. Then I'm gunna order that rebuild kit I posted a link to in an earlier post^ ( just have to figure out the bore size first) .........here's the pics of the cylinder
















I'm thinking its gunna need to be redone it feels pretty coarse


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## joshwyle

make sure ur piston rings are lined up right. i figured they could be lined up anyway as long as the werent straight in line but i broke 1. there is a stop in the groove of the piston and the rings wont seat right if not in the way the repair manual says. just a heads up. good luck!


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## Guest

I guess joshwyle was dead on the money with that one. Good luck hope she runs like a new one. Hope you keep the forum updated.


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## joshwyle

thats the great thing about this site. someone has already had it happen to them. ive found so many answers to problems and fixes on here and every single one came from someone elses experiance. hope all goes well and let us kno how it turns out. good luck and kno if u got any questions u can find the answers on MIMB! if i can help in any way shoot me a PM and ill do my best


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## JoshNate223

Thanks for the warning in the piston rings. I'll keep updates posted. Just redid the set cover tonight. The original one was ripped beaten and faded haha. Not bad considering it was the first time I've ever tried redoing upholstery I guess you could call it haha

















Put this grill in the front the other day too, liked the look it gave it...


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## joshwyle

looks good may just be ur new calling lol


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## JoshNate223

Quick update-- 

Cleaned/honed out the cylinder with 220 grit stone and some wd40. First time doing that, seems to be good... But I'm no expert 

BEFORE pictures are a couple posts up

Now:























In the process of moving stuff around the nipple on the fuel valve snapped off so I ordered I new one for $32 shipped 









And I got the top end rebuild kit in, now it's just a matter of getting the time to put it all back together.









Hopefully my next post it will be running!


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## Polaris425

looks good so far


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## JoshNate223

I got it all back together and did a compression test before hooking back up the fuel lines and all and it only read 50psi. So I did a wet test, and with the little bit of oil in the top it read about 110 psi. So I'm thinking I need to adjust the rings.

I don't have the manual for the four wheeler so I'm not sure what the factory specifications are for what the ring gap is supposed to be in the cylinder. I checked to make sure it wasn't an extremely huge gap/ too small of a gap. Based on just guessing what seemed about right I left them just the way they came, and lined them up on the two little pin things that sit in the grooves in the piston where the gap lines up to.

Also I don't know If its Normal.. But the rings seem to sit pretty loose when they're on they piston, just want to make sure that's not a problem. I can jiggle them around quite a bit while they're seated in the grooves on the piston.

.....any thoughts/suggestions? (Ill post pics of the ring sitting in the cylinder, as well as on the piston, so you can seethe gap as soon as I have the chance to)


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## wolf_36

did you have the carb on , I read you had the fuel lines and all off what is the all , did you have the exhaust off ,

Ring Gap
*.009-.018*​*(.23-.46)*


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## JoshNate223

The carb was on, oil line on was on, exhaust was on.

Just no fuel line attached to the carb.

Appreciate the gap specs, thanks!


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## JoshNate223

I got a feeler gauge and measured the gap, it's where it needs to be (thanks to wolf^). 

I learned that I needed to cross hatch the cylinder, because I was unaware of that before, so I pulled back out the hone and did the best I could 
















It hooked everything back up the carb and the exhaust and did another compression test, still had really low readings( 40ish). 

Before even doing another wet test with the compression tester I just put the spark plug in and sprayed starter fluid in the carb directly after putting oil in the top of the block.... It didn't even try to start.

I'm going after timing now unless anyone has a plan that sounds like it could be it.

One thing.... I don't know how to adjust the timing haha, time to do some research! Any thoughts appreciated guys! From what I understand I have to change something on the starter?


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## james83

i had a 2 stroke jet ski that i redid the top end on and i had to put some 2 stroke oil in the spark plug hole to get the rings to seat then it ran great maybe thats your problem


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## joshwyle

i think the rings have a topside and bottom side 1 side is beveled. not sure if it matters much or not. thats just off memory and my memory isnt great but goodluck


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## Dirty30s

Valves could be way out to don't know if there adjustable or not but I know the brute can do the same all kinds of fuel and spark but no fire and UR choke will not make a differs


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## wolf_36

it's a two stroke no Valves , I think Joshwyle is right I remember having to put the rings in a certain way when I did mine . and timing should'nt have anything to do with compression , timing just sets the spark on a two stroke ... on the bottom of the engine there is a drain is the bolt in it ( I pulled mine out one time when it flooded and forgot to put it back in and could'nt get it to start till I remembered it and put it back in then fired right up )

ajusting the timing is simple but a pain in the butt , you have to adjust the position of the stator behind the flywheel but if your stator is good and you have'nt messed with it I don't think that would be the problem

Also not sure if this played a part but when I first tried to start mine after redoing the top end , I tried starting it with the starter and it would'nt , two pulls with the pull start fired it right up , now it starts either way but always seems like it stars better using the pull start .


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## Guest

If your rings check out pull crankcase plug and see if crankcase is full of gas. Shut off fuel and turn over with crankcase plug out to clear. Put crank case plug back in.Pull spark plug and shoot some WD40 or starting fluid in cylinder and quickly put spark plug back in. Try to crank (pull or kick start will turn motor over faster). it should at least try to hit. Rings may need to break in with a couple of heat cycles from running. If still won't start do a leak down test buy pressurizing cylinder and see if air leaks out of crank seals as these motors do not have reed valves they instead rely heavily on crankcase pressure to draw fuel into the cylinder. Don't think bad crankcase seals will effect compression in the cylinder but will effect starting. I would also make sure you haven't sheared the woodruff key. Please correct me if I am wrong because it has been a looooong time since I have fooled with a polaris 2-stroke. good luck!


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## wolf_36

Your right Goodtimes , And yes if you have tried to start over and over with no luck he is right about the crankcase plug , it will not crank if the crankcase is full of gas


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## JoshNate223

Alright. Thanks josh, wolf and goodtimes. I would be stuck without your help. Checking the crackcase for gas here in a minute. 

I knew the rings were supposed to go in letter writing face up..... Found that out right AFTER I finished getting it the motor all back together. If it still won't start after checking crankcase I'm going to check the rings. But maybe I got lucky or it will run anyway*fingerscrossed*


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## JoshNate223

I drained out the minor amount of fluid out from the bottom of the motor, checked to make sure the rings were facing the right way (letter side up.... They are) 

I'm getting 90-95 psi of compression now, (pulling it with the pull start)

Plugged in the spark plug and sprayed starter fluid directly into the carb and it didn't even try to start. 

Time to pull off the flywheel and check the timing, right? And will I be able to get to the woodruff key from there too?








I already tried to get it off once^ with poor supplies, that main bolt is on pretty good! Ha


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## JoshNate223

And the timing may need to be adjusted because it has a new starter on it from previous owner^^

And I can't think of any other reason why it's not even trying to start right now


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## wolf_36

Have you checked the bore 72mm/2.8346in your compression is still low might be the cylinder it's self causing the problem .


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## JoshNate223

I had the cylinder measured by a shop, they said it was 72mm, ( which is standard size) so that's the size piston that I ordered and put in


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## Guest

I doubt you will have to adjust timing unless someone has fooled with it. Just check to see if key is sheared. If it is just replace key and reinstall flywheel.

Your certain your getting good fire. Can you see a solid spark in daylight. The reason I ask is I ran into a situation one time where I had fire but was hard to see spark in daylight but it was firing. Would not hit at all.


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## Guest

Any luck?


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## JoshNate223

I'm going to re-check the spark. And still have to get that dang flywheel off. Is it possible for the woodruff key to just be partially sheared and that cause the low compression?


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## Guest

JoshNate223 said:


> I'm going to re-check the spark. And still have to get that dang flywheel off. Is it possible for the woodruff key to just be partially sheared and that cause the low compression?


No that won't effect compression. it should crank at 90 - 95 psi. Low but hopefully compression will rise after a couple of heat cycles.


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## ssever121

Hey man i just ran into thus problem with my rebuild. I put the rings on wrong and compression sucked. I took it back down after doing some reading and found that the top ring should have a slight chamfer or rounded edge that should face up. Also be sure to stagger ur gaps 180°. As for the lack of firing off I'd chase the Woodruff key idea but that's only cause that's what the guys above think. Good luck


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## Guest

Did you give up?

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## JoshNate223

I moved out from my parents house where the four wheeler is. But give up? No sir! Just haven't found the time to go work on it


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## Guest

Good deal

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## JoshNate223

Back to gettin' my hands dirty!!

Getting the "resistor nut" off of the flywheel was a challenge.... So I went and bought a new toy....







The impact gun made taking this nut [resistor nut], cake work. It came off like melted butter on a pancake








I'm in search of a flywheel puller now so I can get to that woodruff key and timing. No one local carries any around here. So I guess I'm gunna have to order one online and wait a week or two for it. Feels good to finally get back to it! I'll keep the thread updated


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## JoshNate223

I got the flywheel off without a puller, it wasn't easy but saved me a week and $25.










Looks like I have to buy a new flywheel,









^^^Not sure if the damage was already that way or if it was from beating it with a hammer to get it off haha (...probably the hammer)

Haven't gotten the woodruff key out yet, but here's some pics
















It's stuck in there pretty good. Couldn't get it with a hammer/flathead or pliers. 
My next effort to get it out will be with a pin torch.... If not then I'm breaking out the Dremel.


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## Guest

I could be wrong but I wouldn't heat it up. Replace that front crank seal too if you can without splitting cases. Get a small punch and that key should come out. Whatever you do don't f the keyway up. Good luck!:beer:

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## Tyleraw96

*Wow what happened?*

Fix it?


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