Drifter 440 - CDI Problem? [SOLVED...possibly!]

[drifterdude440]

Well I was pumped to bring my sled out again last Saturday.  It ran pretty darn well up until 6 miles into the trip.  Coming to a stop sign the Drifter started to backfire and lose power.  I could keep it running by fluttering the throttle but it just wouldn't make any power.  I feared the worst. 

I just replaced the ignition coil this summer thinking that was what made the sled die last season (like the kill switch was bumped).  That particular time though, the engine would cool completely and later, I could start it right back up and ride again for a few miles.  This latest snowmobile trip was different though.  At first we couldn't see any spark.  I replaced the plugs (originals were good and brownish).  No change.  I could barely get it to start and when it did, it liked to backfire and makes no power.  I figured we'd leave the sled and let it cool.  I drove another snowmobile, did 137 miles that day, and when going back for the Drifter, it still wouldn't run right.  "Atleast it's still broken" I was thinking...and hoping it was something I could pin point easily.

Last night and tonight I did some tests according to the shop manual.  From what I read here, I'm leaning towards a bad CDI.

PULSER COIL
Measured 22 Ohms (Book says 23 ohms +/- 20%):  Good ... Measured about 3.5 - 4 Vac when cranking:  Good

EXCITER COIL
Measured 122.3 Ohms (Book says 128 ohms +/- 20%):  Good ... Measured a max of 32 Vac when cranking but other readings were lower, around 28 Vac.  The book says it should be 40Vac but I'm using a Amprobe brand DMM and hoping its just the meter trying to average the voltage.  Can I rule the coil to be good?  I'm thinking so.

So I wonder if I should just buy a used original CDI on ebay or go with a new one which is around $120.

Also, I noticed that with the new plugs in, the Mag side plug is much more black...both are wet from cranking when checking voltages.  See below...




I ended up riding another 137 miles that day on a friend's Polaris 600 Tripple.  A beautiful day up near Cadillac, MI...

[drifterdude440]

...Bump.   

[Lloyd (ljm)]

 could be CDI or it might be a spark plug boot. I would try a boot first.

 Was there spark on both plugs?

 

[drifterdude440]

could be CDI or it might be a spark plug boot. I would try a boot first.

 Was there spark on both plugs?

Hmm.  Initially it looked like there was no spark on either plug, then a few minutes later, a white spark on both.  I did replace the ignition coil a few months back and hoped the boots had good connection.  I put some dielectric grease in the connection of the boots hoping that would keep the connections clean.  I can remove the boots tomorrow and see what I find. 

[Lloyd (ljm)]

 If the boots are that new and greased I doubt they are the problem.

 Leaves bad ground, CDI. pulser coil.

 Next time it acts up try unplugging the conecter at the motor, that will eliminate any other problems. Remenber the key switch and kill button won't work with it unplugged.

 If you can get a used CDI I would just to have it.

 Lloyd

[Checkmarks]

Dude,

Before I went in as far as ordering a Cdi you best be checking compression.  Your photo of the spark plugs say scream you got a lean one.  Add to your description of how the old drifter went down and Huston, we have a problem. 

[drifterdude440]

Dude,

Before I went in as far as ordering a Cdi you best be checking compression.  Your photo of the spark plugs say scream you got a lean one.  Add to your description of how the old drifter went down and Huston, we have a problem.

I hope it's not crank seals...I replaced those 400 miles ago (about 3 years ago)...greased the seals and everything as recomended here.  Will check compression too but I really suspect CDI.  At first having no spark to now having what seems to be intermittant spark.  Also, the plugs pictured only have about 30 seconds of run time on them.  Both plugs (pictured) were completely wet after cranking when testing pulser/exciter coils.  The plugs I pulled and replaced when this "no power/bogging condition" happened were both dark brown...more so fouled out.  Plugs have always been close to a chocolate brown.

[jimvw57]

Maybe you got some bad gas?? I made a special trip to get some non-ethanol gas for Waconia. Ended up with a frozen gas line and both sleds ran like crap. I figured the gas must have been sitting too long.

[drifterdude440]

maybe not bad gas....here it goes... 

I hate to speak too soon but, I believe I had a combination of problems!  I believe the CDI was indeed bad and is what caused the sled to bog and die in the first place.  Installing new plugs at the time didn't help the situation.  Since installing new plugs on the trail, I didn't change them again until now... 

Previously, the sled would almost not start, but idled halfway decent, and had no power to "go" on a stand.  Yesterday, I installed the replacement CDI, and it seemed to idle better but no good when hitting the throttle.  Today, I took the plugs out and figured I'd change them again.  PTO plug was hot cocoa brown and the mag side plug, a black oily color on half and white on the other half.  I changed them both, and ran it for a good 20 minutes, ramping up speed (on a stand) and all seems good.  I'm going to keep testing it (on a stand) and might be able to get a last hurrah sleddin weekend in this weekend!

I Definitely appreciate your input on this!  This is a second time where a spark plug problem has thrown me for a loop! (91 GMC Safari spark plug years ago - drove me nuts).

[Tin-man]

Did you ever get this resolved? If so, what was it?

[drifterdude440]

Hi tin-man.  I can't really say for sure yet.  I did run it through some heavy deep snow for about an hour and at higher speeds on a trail recently.  It ran flawlessly then and it was the last chance I had to test it.

Quick history...
After I installed the used (new to me) pulser/exciter coils, I tested it on a stand and it did lose power again.  I found that the newer external coil (made by Parts Unlimited) that I bought a year or two ago to fix the same problem, was bad.  The resistance reading was WAY off.  NOTE: Do not buy any aftermarket coil made by Parts Unlimited.  I was told by a DennisKirk.com tech that the manufacturer is known for coil problems.  I originally bought a pulser coil set made by Parts Unlimited also and it was so far out of spec it was unusable.

I'm hoping to get another chance to ride again this winter.  I will keep you guys updated! 

[5kaws]

Whatever happed to the sled?
It's funny today my 81 intruder 440 and 80 drifter 440 are doing the same thing now !!!!
I have checked everything , and both have new seals,plugs etc   
It's funny both my sleds plugs are the same pto nice brown and mag ghost white. I'm lost
Thanks Mike

[drifterdude440]

Hi Mike,

I actually just fired up the sled today and it seemed to run fine while idling in my driveway.  No way to test it now and probably not for a few weeks yet.  I ran it under some pretty heavy load through deep snow last time out last season and it was a champ.  Not much trail riding though since the fix described above. 

Rob