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Discussion Starter · #1 ·
Newbie poster and newbie skidoo owner. Mechanically adept otherwise.

We have a 2003 Scandic 500F SWT which rarely starts via electric start, but will start religiously every time you pull it - even if done right after trying to electric start - immediately after or after waiting a while.

History - sled was purchased used, no issues mentioned or known. Have used it for a couple seasons grooming a small trail system. Stored indoors during our ownership.

Recently - just picked up the sled today after a complete engine rebuild (full seal/gasket kit and rings). Had a cylinder that was sucking air and running weak. Electric start was an issue before the rebuild, still an issue afterwards, though the mechanics swear it didn't occur for them after the rebuild - they figured they inadvertently fixed it during the rebuild. It only started after the rebuild when I showed up to load it up, and they couldn't get it to work then either - much head scratching.

Several mechanics poked at it before the rebuild, and have no idea how the pull start could work when the electric won't. Apparently there is no spark while trying to electric start, but again, pull start works just fine. A weak battery was suspected, but one mechanic swapped out the battery, and still the same thing.

My history with a range of electronic circuit boards supports it being a CDI issue (no, i don't have one to swap around with to test the theory) - usually when there are bizarre, physically "impossible" occurrences, it's usually a board issue, rather than a mechanical issue.

That said, I'm asking if someone has seen this before, or if they have any supporting facts on why it may or may not be the CDI. I theorize it could also be the key switch (something shorts out in START position, but not in RUN), though I don't have any idea if there's actual circuitry that controls when spark could be enabled/disabled specifically.

Any ideas or help would be appreciated. I'm willing to just buy a new CDI and swap it out, but would rather have a good idea that is likely to work rather than just shooting in the dark, hoping to hit something.

And any other "you should know this about your 500F/SWT" would be appreciated.

Thanks.
 

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Did you try another switch?
 
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3X switch. Or leave the key switch in the run position and jump the solenoid at the starter to crank it (if you don't have a replacement switch handy)...
 

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Newbie poster and newbie skidoo owner. Mechanically adept otherwise.

We have a 2003 Scandic 500F SWT which rarely starts via electric start, but will start religiously every time you pull it - even if done right after trying to electric start - immediately after or after waiting a while.

History - sled was purchased used, no issues mentioned or known. Have used it for a couple seasons grooming a small trail system. Stored indoors during our ownership.

Recently - just picked up the sled today after a complete engine rebuild (full seal/gasket kit and rings). Had a cylinder that was sucking air and running weak. Electric start was an issue before the rebuild, still an issue afterwards, though the mechanics swear it didn't occur for them after the rebuild - they figured they inadvertently fixed it during the rebuild. It only started after the rebuild when I showed up to load it up, and they couldn't get it to work then either - much head scratching.

Several mechanics poked at it before the rebuild, and have no idea how the pull start could work when the electric won't. Apparently there is no spark while trying to electric start, but again, pull start works just fine. A weak battery was suspected, but one mechanic swapped out the battery, and still the same thing.

My history with a range of electronic circuit boards supports it being a CDI issue (no, i don't have one to swap around with to test the theory) - usually when there are bizarre, physically "impossible" occurrences, it's usually a board issue, rather than a mechanical issue.

That said, I'm asking if someone has seen this before, or if they have any supporting facts on why it may or may not be the CDI. I theorize it could also be the key switch (something shorts out in START position, but not in RUN), though I don't have any idea if there's actual circuitry that controls when spark could be enabled/disabled specifically.

Any ideas or help would be appreciated. I'm willing to just buy a new CDI and swap it out, but would rather have a good idea that is likely to work rather than just shooting in the dark, hoping to hit something.

And any other "you should know this about your 500F/SWT" would be appreciated.

Thanks.needs a new trigger coil,the old one has a crack ,had same problem with a 98 swt
 

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I have the same sled, and had the same issue.

The Ducati ignition on this engine requires a certain RPM to make electrical power. A battery that isn't 110% will spin the engine too slow to make electrical power (spark). Trust me, the battery may test ok and spin the engine for hours, but until it can spin it just a wee bit faster it won't make spark. Try boosting the sled with your pickup to prove it.
 

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Just to back up what Dirt Mover said...

The electric starter turns the motor at about 300 RPM.

Pull start is almost or even more than double that on a decent pull.

But that said, what I would first suspect is the spark plug wires and caps. Cheap solution. Replace them. Not real positive on the 2003 coils, but the spark plug wires are typically either pushed in and a clip holds them on or they are screwed on like the spark plug caps. Looking at a parts list, it looks like yours are screwed on. I would just replace them. You can go to NAPA and get the bulk spark plug wires and caps. There is nothing special about them. Typically they are all 7mm.

Here is something I learned about spark plug caps. There is typically 3 metal pieces inside. The screw, bridge piece and the clip. The bridge piece is fairly flimsy metal that connects the screw to the clip, and it really doesn't take much to break them. "But the engine runs fine" You have to remember, the spark can still jump across a gap. When the bridge breaks, it is often almost zero gap, just a bad connection. Low RPM start = lower voltage/power = harder to jump the gap. Once the motor is running, it jumps across that gap as easy as it produces spark.

Even if that is not the issue, it is a cheap (usually less than $30) piece of mind.
 

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Discussion Starter · #8 ·
Just realized I never followed up on this issue.

The solution (? - what worked anyway) was that we replaced the CDI, which included spark plug wires and caps. I personally didn't do the swap, but they say it fired right up afterwards, and did so all season long - and we got a lot of snow in February to give it a good test.

Thank you for all the help - much appreciated. Hopefully we get several years more use from this machine - it grooms like a beast :)
 
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