HELP!! Engine problems - Snowmobile Forum: Your #1 Snowmobile Forum
http://www.snowmobileforum.com
Go Back   Snowmobile Forum: Your #1 Snowmobile Forum > Specific Snowmobile Forums > Polaris Snowmobiles


» Sponsors





Reply
 
LinkBack Thread Tools Display Modes
Old 01-26-2012, 06:39 PM   #1 (permalink)
Registered User
 
Formula's Avatar
 
Join Date: Oct 2011
Location: Gatineau, QC
Posts: 43
HELP!! Engine problems

Where do I begin? I've had so many problems with my 2000 Polaris XC SP 700 and have spent so much money trying to fix the problems that it would make someone sick.

I had coolant running in one of the cylinders so I decided to change the head gasket and the gaskets on the top end. Then I had no spark so brought it to a mechanic and my stator pick up coil broke off so they replaced the stator. Now The machine starts but backfires like crazy, runs like real ruff and won't pass 3000 rpm because it bogs and backfires again. Also, when I pull on the pull cord it seems like it wants to rip out of my hands for some reason.

Any thoughts on what the new problem is?

Thanks
Formula is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 01-26-2012, 07:01 PM   #2 (permalink)
Registered User
 
scrammy650's Avatar
 
Join Date: Dec 2010
Location: newyork
Posts: 1,057
try a compression test clean carbs if have them maybe try draining any gas out nof crankcase plugs
scrammy650 is offline   Reply With Quote
Old 01-26-2012, 08:48 PM   #3 (permalink)
BAHNN Motorsports
 
Join Date: Mar 2010
Location: Mankato, Minnesota
Posts: 189
turn off fuel lever, remove both plugs, stand back and pull it over....the cylinders may be full of fuel from having no spark. If this is the case keep pulling until both cylinders are clear. Next remove the pipe and drain fuel as there may be a boat load inside and like scrammy said, remove both crank case plugs located on the bottom front near the engine plate and drain fluid. I think the crank case plugs are 7mm or something in that range and let us know the result
__________________
Quality used OEM Polaris snowmobile replacement parts bahnnmotorsports@gmail.com
Bahnn120 is offline   Reply With Quote
Old 01-26-2012, 09:59 PM   #4 (permalink)
Registered User
 
Join Date: Jan 2012
Posts: 66
hate to be so simple but id check the seal on both of the plugs also
jagump is offline   Reply With Quote
Old 01-28-2012, 07:50 AM   #5 (permalink)
Registered User
 
Formula's Avatar
 
Join Date: Oct 2011
Location: Gatineau, QC
Posts: 43
Quote:
Originally Posted by Bahnn120 View Post
turn off fuel lever, remove both plugs, stand back and pull it over....the cylinders may be full of fuel from having no spark. If this is the case keep pulling until both cylinders are clear. Next remove the pipe and drain fuel as there may be a boat load inside and like scrammy said, remove both crank case plugs located on the bottom front near the engine plate and drain fluid. I think the crank case plugs are 7mm or something in that range and let us know the result
We pulled the drain plugs and a bunch of coolant and gas came out of both plugs. We pulled the engine over 20 times with the gas off and the plugs off and still runs the same. Because the stator was just replaced we decided to pull it off again and the timing mark wasn't lined up so we lined it up and checked it with a timing gun but the machine still runs the same. Also checked the reeds, the ohms on the new stator and made sure both pistons are firing by pulling the wires while its running. After pulling the plugs, one has oil at the bottom of it and the other is clean with a bit of a gas and they were brand new plugs before putting them in. The only thing I haven't checked is the carbs which I plan on doing today but I doubt that the carbs are the problem. It still idles at 500rpm and won't go pass 3000rpm full throttle without backfiring and the engine sounding like it's about to blow up.

Besides the carbs, could it be the timing is still off and are we timing it correctly with the gun?
Formula is offline   Reply With Quote
Old 01-28-2012, 07:51 AM   #6 (permalink)
Registered User
 
Formula's Avatar
 
Join Date: Oct 2011
Location: Gatineau, QC
Posts: 43
Forgot to mention, the compression is at 122psi on each piston.
Formula is offline   Reply With Quote
Old 01-28-2012, 09:36 AM   #7 (permalink)
Registered User
 
Join Date: Sep 2011
Location: Caldwell, Idaho
Posts: 155
You had "Coolant" draining out of your case?! Best case scenario.....bad head gasket. Coolant and fuel should never be in the same place. Worst case scenario....cracked block/cylinder! Pull the head off and hope it's just the head gaskets/o-rings.
robhill1965 is offline   Reply With Quote
Old 01-28-2012, 09:39 AM   #8 (permalink)
Registered User
 
Formula's Avatar
 
Join Date: Oct 2011
Location: Gatineau, QC
Posts: 43
Quote:
Originally Posted by robhill1965 View Post
You had "Coolant" draining out of your case?! Best case scenario.....bad head gasket. Coolant and fuel should never be in the same place. Worst case scenario....cracked block/cylinder! Pull the head off and hope it's just the head gaskets/o-rings.
Thanks for the reply, i've already done the head gasket and o-rings because it was leaking coolant on the mag side. I think this new problem is related to something else.
Formula is offline   Reply With Quote
Old 01-28-2012, 09:54 AM   #9 (permalink)
Registered User
 
scrammy650's Avatar
 
Join Date: Dec 2010
Location: newyork
Posts: 1,057
like stated above shouldnt be no antifreeze
scrammy650 is offline   Reply With Quote
Old 01-28-2012, 01:17 PM   #10 (permalink)
Registered User
 
Formula's Avatar
 
Join Date: Oct 2011
Location: Gatineau, QC
Posts: 43
So had a mechanic come by and he has diagnosed the problem as a timing issue. Now the only think I need to figure out is if the timing is too advanced or too retarded. Does anyone know anything about timing? Should I advance the timing or retard it for it to run past 3000 rpm without backfiring?
Formula is offline   Reply With Quote
Old 01-28-2012, 07:49 PM   #11 (permalink)
Registered User
 
Join Date: Oct 2008
Location: connecticut
Posts: 615
hello coolant in the base water doesnt burn if you did the head oring and the base gasket and it didn't fix the coolant issue then you have some major over hauling to do and you can change the timing all you want its not going to fix a thing.sounds like you got a sled that blew a crank and they patched it back together to get it to run and sell.if the crank is twisted then your timing will always be off and if the crank cracked the block or crack a cylinder your coolant wont stop.if you owned the sled for awhile and it ran good then started this i would say you hydro locked the engine from the coolant being the base and bent a rod or twisted the crank.
ppolaris1010 is offline   Reply With Quote
Old 01-28-2012, 09:04 PM   #12 (permalink)
Registered User
 
Join Date: Jul 2011
Posts: 26
I had coolant getting into my cylinders too. i replaced gaskets and what not and it fixed it, but did you completely drain the engine? crankcase, and all? cause you might've had coolant from the original issue.
keller772 is offline   Reply With Quote
Old 01-29-2012, 08:54 AM   #13 (permalink)
Registered User
 
Join Date: Sep 2011
Location: Caldwell, Idaho
Posts: 155
As stated above....You need to be absolutely sure the coolant issue is solved before you worry about timing.
As for where to time it... Just call your local dealers' shop and they can give you the specs. Put it at the factory specs. The only reason you would advance it would be if you are consistently racing it at high speed or if you've machined the intake/exhaust ports or changed the stroke of the piston rod. Factory timing will fire your spark plug just as the piston passes and closes the intake port. If it fires sooner, the fuel explodes "before" top of the stroke and will try to push your piston backwards instead of powering it forward. If you retard it, it will fire too late and you loose the maximum compression.
robhill1965 is offline   Reply With Quote
Old 01-29-2012, 09:34 AM   #14 (permalink)
Registered User
 
Formula's Avatar
 
Join Date: Oct 2011
Location: Gatineau, QC
Posts: 43
Thanks for all the replies. Pardon my ignorance, i'm still newish at fixing snowmobiles.

keller772 - When we replaced the head gasket, there was coolant in the crank and we tried to get most of it out with a rag and pulling the drain plugs. We pulled all the coolant lines an drained them as well, so there was a bit of the old coolant still left in the rads that I couldn't drain.

Polaris1010 - I've owned the sled for a couple of months now and the 3 times I took it out so far this year, it ran fantastic. The last time it died because my pickup coil broke off and that's when I noticed that there was coolant coming from the mag side piston so we replaced the head gasket, o-rings and installed the new stator. Since then it hasn't ran right. If the crank was cracked/twisted, would it still start/run?

Since my last reply, last night we pulled the crankcase plugs and lifted the back end high enough to drain whatever else was in there but all that came out was a bit of gas, no more coolant came out this time. We ran it for 15 mins, still runs ruff and backfires like crazy when you give it full throttle and it won't pass 3000 rpm. We pulled the drain plugs again after running it and a little bit of gas came out the holes not much to say that there's a leak. We also pulled the plugs and they seems to be burning ok, they do have gas at the end of them with a little bit of oil and when the machine is running there's bluish smoke coming out which burns the eyes like crazy. Normally that's oil right?

Based off of everyones replies and asking other snowmobiling friends, the only other 3 things it could be is:
- Carbs aren't working right (have completely cleaned both of them yesterday and engine still runs bad)
- Twisted crank or bent rod (how do I check this?)
- Short in the electrical system (cdi is good and so is the stator. Where else do I start?)

Thanks again for your help everyone, I wouldn't have gotten this far without this forum!
Formula is offline   Reply With Quote
Old 01-29-2012, 10:00 AM   #15 (permalink)
Registered User
 
Join Date: Sep 2011
Location: Caldwell, Idaho
Posts: 155
Sounds like you've fixed the coolant issue so..
Often, the last thing you did, or things around the last thing you did are the culprits when a "sudden" problem shows up.
I would definitely look into the timing issue since you replaced the stator recently.
If you're finding fuel in the crank case....(depending on how much), you may have a "rich" condition. Double check the cleanliness of the carbs and pay extra attention to the choke and floats. Make sure the floats are not leaking and that they are level when you hold the carb upside down. Make sure you are using fresh gas. Snowmobiles are absolutely notorious for being picky about old gas or water in the gas.
Again, if it ran good before and you changed the stator, I'm leaning towards timing but checking the fuel system is just good measure and rules it out.
robhill1965 is offline   Reply With Quote
Old 01-29-2012, 10:04 AM   #16 (permalink)
Registered User
 
Formula's Avatar
 
Join Date: Oct 2011
Location: Gatineau, QC
Posts: 43
Quote:
Originally Posted by robhill1965 View Post
Sounds like you've fixed the coolant issue so..
Often, the last thing you did, or things around the last thing you did are the culprits when a "sudden" problem shows up.
I would definitely look into the timing issue since you replaced the stator recently.
If you're finding fuel in the crank case....(depending on how much), you may have a "rich" condition. Double check the cleanliness of the carbs and pay extra attention to the choke and floats. Make sure the floats are not leaking and that they are level when you hold the carb upside down. Make sure you are using fresh gas. Snowmobiles are absolutely notorious for being picky about old gas or water in the gas.
Again, if it ran good before and you changed the stator, I'm leaning towards timing but checking the fuel system is just good measure and rules it out.
I'll pull the carbs and check the float/choke again. I think your right that it may be fuel related because of the backfiring. If it is timing, how do I check it with a timing gun? I matched up the mark on the water pump housing with the stator and saw a sticker on the flywheel that has 0-50 degrees rating on it. should it be showing 0 when the engine is running?
Formula is offline   Reply With Quote
Old 01-29-2012, 10:12 AM   #17 (permalink)
Registered User
 
Join Date: Sep 2011
Location: Caldwell, Idaho
Posts: 155
Carbs will cause a "sputtering" or running hard. If it's "backfiring", that means the spark is firing "before" the piston reaches the top of it's stroke and the intake port is still open so when the spark fires, it sends some of the ignited fuel back through the carbs.
You'll have to call the dealer if you can't find a manual to get the timing specs. You're going to set it with the engine "off". It's likely going to be slightly advanced past "0". It will automatically advance while running depending on the rpm's as the spark needs to fire sooner and sooner the faster the engine goes.
robhill1965 is offline   Reply With Quote
Old 01-29-2012, 10:23 AM   #18 (permalink)
Registered User
 
stanage's Avatar
 
Join Date: Aug 2010
Posts: 4
To see if the rods are bent, you need to check for rod deflection, and rod trueness. It requires a complete teardown. You would also need to setup the crank on v-blocks and check all the crank weights for trueness as well. A good machine shop can do this.

To test the electrical, requires the wiring diagram, a good meter that has continuity testing ability. Test all your wires to ground/chassis. If any of them come back as continuous, check the diagram because it means the wire is touching the chassis.

Make sure you blow out all the passages in your carbs with compressed air after you have cleaned them. Simply using carb cleaner won't get them entirely clean. Make sure the choke plunger orifices are clean, dirt will obstruct the movement of the plunger and could cause you to run very rich on one cylinder.

If, after changing your head gasket, you still have coolant leaking in the cylinders, then that jump you took was was way too big

Timing is 12Degrees BTDC(Before Top Dead Centre) @ 3000RPM
stanage is offline   Reply With Quote
Old 01-29-2012, 10:40 AM   #19 (permalink)
Registered User
 
stanage's Avatar
 
Join Date: Aug 2010
Posts: 4
How to check your timing,

You need these tools for "accurate" timing (Ignore the "arctic cat")

Micrometre with sparkplug adpater
Arctic Cat - Dial Indicator Timing Set - Starting Line Products
Degree Wheel
Arctic Cat - Degree Wheel - Starting Line Products

Instructions:
http://www.slp.cc/instsheets/New%20Timing.pdf

Call me when you want to do it!
__________________
89 Exciter 570, Port & Polished, PSI piped, Custom cold air box, 96 Vmax T.S.S struts and widened to 42", stage 2 strut valving and stage 2 sway bar, Fully Rebuilt Stock Skid, Custom 136 Rail Extensions and custom tunnel extension, 136" Camoplast Cobra track 1.35inch paddles, Graphite Sliders, Camoplast all-terrain camo skiis, rear end dropped 2 inches. My Widdle Powda Killa :letitsnow:
stanage is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 11:47 PM.



Copyright SnowmobileForum.com

Search Engine Friendly URLs by vBSEO 3.6.0