Craftsman single stage 536.884442 snowblower

This model has an electric starter. when I power the starter and press the button, the starter just spins without actually engaging the engine. I can see the gear on the starter slide towards the engine but it looks like it is already spinning so fast that it doesn't actually engage the engine gear. The starter gear does not look or feel damaged but then again, I don't know what it should look like. The starter gear does slide along the shaft as it spins.

Any ideas on how to get the starter gear to engage the engine gear? Video of the problem is attached.

Video of broken starter

-Peter

 

Verify the starter gear engages the flywheel teeth by manually moving the starter gear along motor shaft. If no engagement loosen starter mounting bolts and adjust starter position until teeth engage and tighten mounting bolts.
If the teeth engaged initially, you need to lube the starter motor shaft in the area where the starter gear slides. If you can't access this area with the starter installed you will have to remove the starter. Good luck

 

I was able to easily slide the gear across the starter shaft by hand and engage the gear on the engine. I also sprayed some WD40 on the shaft for a quick test but it did not make a difference when the starter spun up. I know WD40 is not a good long term lube but it it should have lubricated it enough for my testing.

Other thoughts?

- Peter

 

Take the starter off and hook up the cable and ground the case of the starter. Then switch the starter on (watch your fingers. See if the starter gear jumps up the shaft. If it spins up the shaft, the mounting of the starter may be the problem.

If the gear is spinning but not moving up the shaft, the battery may be low.

 

Check your battery first, Starter needs a full charged and good battery to work.

 

Most of these SnowBlowers utilize an AC Starting system (thank goodness).

 

That's right, Vermont. I haven't see any small ones with a battery to think of it.. They are either AC or manual.

 

I like the idea that they're equipped with BOTH; an AC Starter (w/o battery complications) AND a manual recoil starter. The AC Starter spins the machine so fast that minor carburetor problems can be tolerated (not so with the Recoil, especially on -40°F days when the power is out !)

I always start my SnowBlower close to my Barn or Garage using the AC; but if I have the misfortune of running out of fuel (never intentional) more than a few hundred feet away from power, I can still rely on the recoil.

For the OP, it may be that the Pinion gear (nylon?) has gotten stuck down at the bottom of its shaft. It relies on centrifugal force to travel up the shaft to engage the flywheel.

I've been told that it is essential that the gear itself and the shaft be clean, and free of grease; that just gathers up crud to restrict the free movement of the Pinion.

Look and see if the teeth of the Pinion are still intact. It could be that, depending upon the history of the machine, the teeth were damaged sometime when the flywheel wouldn't budge . . . . even though the Pinion traveled to the end of the shaft. If so, just replace the Pinion; NOT the entire Starter Motor.

 

Oddly enough it isn't centrifugal force that moves it up the shaft. It's the shaft spinning inside the gear. I don't know how the light weight nylon gears even work.

 

thanks marbobj, you are correct. I pulled the starter and the gear has a smooth bore and is made of metal. There is a separate disk/washer that is grooved and rides the grooves on the starter shaft. When the starter rotates, the disk can ride the grooves ad pushed the gear towrds the engine gear. It took a little wd40 and some manipulation but that arrangement is now operating freely. When the starter spins, the disk and the gear move down the shaft towards the engine but does not engage. I think the gear is spinning too fast to engage so it just rubs against the face of the engine gear. I am able to push the starter gear into the engine gear to engage it so there is nothing blocking it or out of alignment.

I am just not sure what else I can do. I did reassemble it to use just the manual pull start but if someone has a high probability fix, I am willing to tear it down again.

- Peter

 

Is the gear itself connected to the shaft? Maybe when the gear engages the ring gear on the flywheel the shaft is just spinning inside the gear and not driving it.

 

Interesting point. The gear on the starter has a smooth bore so if it actually did make engage with the gear on the engine, I am not sure how it would turn it. Never the less, as seen in the video link in post #1, the starter gear does not engage with the cogs on the engine so the gear on the starter just spins endlessly against the face of the engine's gear.

- Peter

 

I just looked at the video. I missed that it was posted. From where the starter gear is positioned at the start of the video - against the end washer - if you can spin that gear on the shaft that's the problem. The gear isn't connected to the groove in the shaft. There is something stripped. It could be the groove or the tracking device on the gear.

It looks like there's enough left to move the gear up to the flywheel gear, but not enough to force the gear mesh. Then the gear falls back away from the flywheel. The starter gear should only turn with the shaft and not just on the shaft.

 

The washer is actually the part that is grooved to match the groove on the starter shaft. It may not have appeared so in the video but after I cleaned everything last night, the washer does spin down to push the gear towards the engine. There bore on the starter gear is totally smooth with nothing to suggest it was ever grooved. Because there is nothing to hold the washer or gear from spinning, if the initial torque spin of the starter gear does not spin the washer towards the engine then the washer and gear are spinning at the same speed as the shaft and nothing is going to move.

I am beginning to think that we are diagnosing it as we think it should logically work but not as it actually does. Maybe someone have this model or worked on one like that can tell me more about it. Some of my questions mirror marbobj's:

Is the grooved washer on the starter shaft supposed to be separate from the starter gear or is it supposed to the one piece?

Are they supposed to spin together or does the grooved washer really just push the gear down the shaft?

It has to be more than luck for the starter gear to align with the cogs on the engine gear. If it misses, it will never match because the starter gear is already spinning too fast.

Sears does not show the part number for the starter gear. Does anyone have that number available?

- Peter

 

Post the make and model of the engine, Sears only shows the engine as not available. An IPL of the engine should have a parts breakdown of the starter and the drive assy.

 

The meshing of the starter gear to the flywheel ring gear is forced, not alignment. But the rotation of the starter gear is only about one and a half rotations from the outer end to the flywheel gear. It doesn't just spin and fly into the ring gear. The offsetting of the gear teeth is compensated for by the bevel on the teeth.

The starter gear has to be fixed directly to the shaft by one means or another. The gear and washer with the dogs on it to drive it up the shaft may very well have been one piece. There is a slim chance there could be or have been a fiber friction washer in there, but that would be an unusual setup.

 

After watching the video, that is a bit different setup for the starter. I can not make out the ring gear on the flywheel, but the gears on the starter drive look to be too beveled, or worn.

Again, with the engine info, I might be able to find some more detailed illustration.

 

The engine is tecumseh 143.944571 3190G. The starter is tecumseh #590670. What is the starter gear supposed to look like? Are the gear and the washer separate pieces?

- Peter

 

I did the parts lookup myself and it looks like I am missing a spring number 590644. Any thoughts?

 

Go to this link at Sears:Lawn & Garden Equipment Engine Starter Pinion Gear | Part Number 34949A | Sears PartsDirect

It really looks like what we've been talking about. The drive on the gear has separated from the gear. The starter can't drive the gear to drive the flywheel if it isn't connected to the starter shaft. That's a little different from other starters in that the gear is being pulled up the shaft rather than driven down the shaft. Other than that it works the about the same.

Looks like the fix is about $20.

 

Problem solved. Here what I did and what I learned.

I bought the "starter drive pinion", tecumseh part #590644. It installs between the starter gear and the starter drive nut. As noted above, there are no threads on the starter gear so it spins freely on the starter shaft. Couldn't really figure out how that would be productive until I realized the drive pinion was missing. The pinion is a piece of rubber that creates friction between the drive nut and the starter gear.when the starer spins up, the drive nut spins down and pushes the pinion into the starter gear and spins the gear with friction. When the starter stops spinning, the drive nut spins back up to the end of the starter shaft and does not have any connection to the starter gear. Because there are no threads or splines on the starter gear, it continues to spin freely even while in contact with the operating engine.

Identifying that a part was missing was critical. My parts guy said it is not uncommon for rubber parts on older machines to dry up and crack. Then it falls off and then you never know you what you are missing.

Thanks for all the conversation and ideas.

- Peter

 

That would be very unusual for that gear to remain engaged with the flywheel and no lubricant on the shaft.

 

Did you check to see if the Starter is loose? That is the problem I'm having with mine.. If the Starter doesn't engage the flywheel and is just spinning then it may not be lined up and thus be loose.. I have to continously keep checking to see if the starter is loose...I've noticed another problem(?) The starter gear seems to flex left to right.. Don't think this is normal

 

The starter on my Troy built snow blower stopped turning the engine.
When I push the starter button the starter try’s to turn the engine but the stops and it makes a humming noise as if it is locked up.
I removed the starterand on the bench the bendix drive jump out momentarily when energized.

 

First take out the spark plug and see if the engine turns over either by rope starter, manually, or maybe the electric start.

If it turns over freely, the starter may be worn out. It may have worn out windings, a bad armature, or worn brushes not making contact. Sometimes, in the case of the brushes, just tapping on the starter with a block of wood can shake them loose and get the starter going.