2000 indy wont start, low compression, worth rebuild?

[jonesin]

my 2000 indy has 7500 miles, top end was rebuilt at 5200
last year it would not idle down on its own, I sprayed started fluid everywhere except under the lower crank cover with recoil on it with no effect, I assumed I had a bearing going out behind the cover...
last week I got it out and it was running on one cylinder. I found 2 wires from the cdi had been rubbing on the pull chord and the rubber was wore through.
I repaired the wires and suprise, it ran great and even idled down on its own for some reason, (probably coincidence?)
I decided to take it for a ride, put new gas in and left only to have it die 15 minutes later....

it only has about 85 psi compression
it has spark and appears to be getting fuel
when you pull to start it, the lights only barely glow which is unusual

did I just have something else go out or did the rings just finally burn up?
what causes the lights to power when you pull start it, what does the stator or magneto do on a sled without batteries to charge, does that run lights and would it have anything to do with starting?
I am baffled but I came here first without even looking up schematics yet...

I have owned it since new and it was rode extremely hard most of its life but it is mainly just used by the kids to play around or me to go cut wood at this point, its definately worth a complete rebuild I think....

Thanks ahead of time for your ideas and opinions, I am sure that I will get a bunch of them to try!

 

[raceinsnow]

I would like to know if you had 85 psi in both cylinders. 85 psi is low, but it depends on your gauge and how you are using it. If you have spark then I would believe that the stator would be fine. I would look at the fuel system better. Water in the gas is a big problem. also on that sled the fuel line that is in the gas tank gets brittle and breaks off in the tank so look at that. Try and see if the motor will start with the starting fluid, if it will start then look at the fuel system. "Most" times when a motor quits running because of a piston problem you would have almost no compression in one cylinder. Hope that helps and that's something to start with

 

[jonesin]

one cylinder was about 80 and the other 85
I hooked the fuel line in the tank and pulled it out, the screen was clear and the line was not brittle or broke
the sled had very little fuel in it so I added 5 gal of fresh gas

it was running great and then just lost power and when I came to a stop it coughed once or twice and died

it just seems odd to me that when i pull the chord my dash and headlight dont shine bright like it normally did, they are so dim I couldnt see them light unless i turned off all the lights in the shop....

Thanks!

 

[rmk4ever]

The dimming of the lights is caused by a problematic hi /low switch on this model... I still have a 2000 rmk that has this problem every year after storage. Some times just switching back next forth will cure it. Some times you have to open the switch & clean contacts. 80 psi is low. Time for new slugs / bore job. Good luck.

 

[jonesin]

when it was running the lights were working fine, its just when I am pulling the chord that the dash and head light would glow bright on each pull, now next to nothing...

 

[jonesin]

the 80 psi wouldnt stop it from starting and running would it? Just loss of power ?

 

[ezra]

it would start harder with low comp but should start . u should have those jugs investigated before just slapping new pistons in . could be out of round and that is why u lost compression so son this last time . deff should last more than 2300mi on a top end

 

[formula_iii]

So you have an idea...I just checked my compression on 2003 indy 500 120 each cylinder with 5700 miles... My lights get brighter as rev engine and sometimes have to flutter the throttle to get to idle down esp when first started then she's fine..
I agree with ezra, I'd check the cylinders as 2300 usually too early for top end...

 

[jonesin]

I checked compression again last night about 85 on both
I double checked and I am not getting fuel from the tank, I think the fuel I saw on the plugs and spraying in the air from the plug hole when I was doing the comp check was from crank case or something
I blew out the line in the tank, new fuel filter
I rebuilt the fuel pump even though it looked perfect
I dont think I am getting enough vacuum or compression from the bottom of the motor to work the fuel pump to draw the fuel...
The fact that it kept idling up high last year had me thinking the crank seal was going out, maybe it finally did.... maybe its sucking in air ...
I have never rebuilt a 2 stroke, maybe its time to pull it out of the sled and bring it in or take it apart....

 

[G]

Does the hose that runs from the crankcase to the fuel pump fit nice and tight? Are there clamps missing on it? You can't have any leaks there or the fuel pump won't work. It should run with 85 but it is weird that both are at 85. As has been said a top end rubuild should last more than 2000 some miles. Did you put anything weird down the spark plug holes when you summerized it? Maybe the rings are stuck. ??????? Strange. Sleds from that era had high idle problems even on a good day. Yours has a lot of miles on it and your high idle could be a result of worn carb slides. Common problem.

 

[jonesin]

I couldnt hardly get the hose that runs to the case off the pump, it was TIGHT!
I sprayed a little oil in the cylinders and treated the gas last year, same as always...
it started on 7-8 pulls after sitting all summer and would start in 2-3 pulls every time after that which is what it has done for 15 years.... right up until the last ride....
I feel it has to be what ever makes it pump the fuel at this point which is why I am leaning toward the crank seal, if that going out would do that....
when i put my finger over the hose and pull the starter chord you can feel little puffs but its not strong, and there doesnt appear to be any vacuum, I am not sure if there is supposed to be any suction though... if the little puffs of air are what work the diaphram in the pump and the crank seal is out it would allow the pressure to leave the case instead of run the pump... that is what I am thinking... sound right?

 

[jonesin]

on the positive
IF the crank seal is out and causing this then its possible the pistons and rings are good then when rebuilding hopefully the cylinders are still good
I could get the cylinders checked and new rings but re-use the pistons.... right?.....

 

[G]

Little puffs are what you are supposed to be feeling. If you are getting your little puffs just by pulling the rope I have to believe that everything is OK there. I can't find anywhere where you say which size engine you are dealing with. There were some Pols that liked to eat crank seals but they were mostly the 800's. The 5's and 6's and 7's were good for the most part. Also a bad crank seal would not explain your low compression. Bad seal or not it should still develop compression. Here is what I would do if it were mine :

Take the spark plug wires off.

Take off the fuel lines that run from the fuel pump to the carbs.

Make sure there is fuel in the tank.

Find a guy with big arms.

Have him pull the starting rope like a madman while you observe the gas lines to see if gas comes out.

If it has electric start you can eliminate the guy with big arms.

If it is pumping gas like I am guessing it will then you have to move on to the carbs to see what might be going on. This still does nothing about the low compression. But it should start. You might have had a problem at the end of last year and some obstruction in the carb (s) caused fuel starvation and you stuck a ring (s). THAT would explain a lot of things. The easiest way to check for that is to take off the muffler and then the Y pipe and peer into the exhaust ports. This should be easy on this model. Take out the plugs and use the driven clutch to rotate the crank/piston assembly. If you see scoring on the piston next to the ring(s) then you have most likely burned it down. If the rings are partially melted in to the piston or are broken this is what is causing your low compression. It will have to come apart. See what you find. Good luck.

 

[jonesin]

GRUB, lol, guy with big arms... they arent as big as they used to be

that is what we did last night, except for taking off the exhaust, and couldnt get a drop out of it, maybe I didnt pull hard and long enough... I didnt fall over on the ground when done....
of course, after blowing out the feed line there was no gas to start the flow or pumping either
I can add more gas, jack up the back end to try and get fuel to gravity feed the line to the pump prior to putting it on and "prime the pump" so to speak and then try to see if I can get fuel to pump out

its an indy 500, it ran good right up to when it died
when I pulled the fuel lines off the pump they did have fuel in them and when I took the pump apart it had fuel in one side of it you could visibly see sloshing around.....
Thanks so much for the ideas and discussion, it helps motivate me to keep searching, I pretty much was writing it off as needing rebuilding...
I just want to get it running for the kids this winter and then do the whole motor....

 

[G]

Yes on those the fuel pickup kind of runs uphill so you need a fair amout of fuel in the tank just to get the pump primed. Fuel pumps hardly ever fail. And if you have gone through it I really doubt if that is your problem. And again if it is 500 those were pretty rock solid as far as crank seals. However it is getting old now. Anything is possible. To prime it also works to use compressed air. Take the filler cap off the gas tank and wrap a big rag around your air squirter and direct it into the filler hole for exactly 32 seconds. Oh wait it is a 500. Try 34 seconds. That should get the fuel to the pump and you can eliminate the big arm guy. Really it is not a big job to take the exhaust off and look into the ports. I would do that.

 

[jonesin]

I will look in the exhaust port, I sprayed the nuts with stuff to make it easier to get them loose last night
I did that last year when I was trying to figure out the high idle thing and they looked fine
My compressor isnt very big, it will probably take a few extra seconds , I'll add more gas also....
I also cleaned carbs a couple times last year with no change in performance....
the pump looked perfect when I took it apart but decided to rebuild it anyway just to eliminate that piece from the puzzle

the starter rope had been rubbing on the cdi wires for who knows how long so the wires could have been bare for who knows how long without totally killing that cylinder, it shocked me when after fixing that it idled down fine
I told myself not to get my hopes up and that it was a fluke, I even jokingly said that they run best before blowing up and I would probably have to walk home as I left for my ride... jinxed myself
Im leaving work now, will spend some more time on it over the weekend
again, thanks for the input!

 

[G]

Upon further thought - If you have only 85 in each cylinder there is a reason for it. You might have some piston/ring damage that is not yet severe. As in the jugs are not wrecked - yet. If you were to get it running the pistons/rings will not magically heal. They will get worse until they potentially wreck the jugs. Which means $$$$$$. It is odd that both are at 85 but I have seen where a ring breaks on one side and goes out the exhaust port and then gets sucked around into the other exhaust port and screws up that piston/ring also. You need to find out why the compression is low. Even if you got it running for your kids - and I am understanding your thought process here - it would run until it got warmed up and then it would stick a ring lightly and die. Time after time. Your kids will not be impressed and decide that snowmobiling sucks and take up meth or sex with goats. We can't have that. We need them for the future of the sport. Really - you have one of the most fixable, user friendly motors ever made. It is a simple easy to get at motor. Don't be afraid of it. Have at it. If you had a new sled you would need a young priest and an old priest just to even FIND the motor. Get some Bud Light and a coulple of buddies that know everything - we all have some of them - and get dirty. Take off your Y pipe.

 

[dmsrx]

You can fill the float bowls by disconnecting the fuel lines at the carb, make up a different set of lines with a Tee in it to connect to the carbs, and put a small funnel on the end of a line going to the Tee. Just pour gas in the funnel and it will fill the bowls. If its a fuel delivery issue this will bypass all the rest of the system. If it starts and runs then the pump will prime as well while it runs on the fuel in the bowls. If it starts you can keep adding fuel to the funnel too so it runs long enough to see if the pump works and delivers enough fuel to run the sled. I do this when I clean carbs. A lot easier than having big arms and pulling like a madman.

 

[jonesin]

I didnt do anything with it over the holidays but finally messed with it last night
I pulled the exhaust y off and removed the plugs, what I could see of the piston, rings and cylinders all looked good, no chips or excessive carbon buildup, looked pretty clean and shiney
I took apart the airbox just to make sure there were no mice nests and it was clean
I hoisted the rear of the machine up high, plugged the gas cap with a rag and filled with air and fuel ran out of the lines to the carbs
tried to start it and it "almost started to run" once but that was it, kind of sputtered for a second....

If I have a bad crank seal, would that affect the compression reading? I would not think so
If I have a bad crank seal, would that allow it to suck to much air to start?
I am not afraid of rebuilding the top end, just not sure what to do about the bottom, there must be valves and stuff that are old too....
It was running so good right before it died that I am confused as to why it wouldnt at least start... I called a couple local guys that rebuild motors but havent gotten a call back, about ready to yank it out and tear it apart to see what I can find....
thanks again for the input!

 

[jonesin]

I also pulled the recoil housing off and didnt see anything leaking from behind the flywheel, if the seal was bad I expected to see a mess....