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MTD 990 Twactor Guy
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Discussion Starter #1
:banghead3 This "new to me" 990 is driving me nutz!

Having bought it at a lawn & garden salvage yard, there was no battery and no way to start it, so I drug it home in the hopes that there wasn't anything majorily wrong with it. Tried to go about reviving the old 990 the right way - changed all the fluids, new gas line, cleaned the gas tank, new spark plug, etc. Not having any manual, I was wingin' it. Just had to find out if this thing was going to start, so I put a little gas in the tank, hooked up a brand new battery from my Craftsman LT1000, and hit the key. It turned over a couple of times, and then made a kind of whirring sound, so I stopped.

Not starting, I pulled the plug, but left on the plug wire to check the spark. Hit the key - nothing - not even a flicker. To shorten this up, I'm trying to pull the flywheel to get at the armature / points / condenser - the flywheel won't budge! :banghead3

The front pully came off easily, the retainer clip popped off, and the threaded retainer came off fairly well after a little WD40, but not the flywheel! I'm using a flywheel puller, but it's not moving. Did I miss something else holding it? I'm trying not to beat on it because I know that you can't buy another. I need some expert advice from someone who's pulled their flywheel off before! Pleeze! :thanku:

Oh, yeah - almost forgot - on the armature, there's a wire connection with two black wires coming out. One is attached to a ground and the other was cut off and taped over. Is that right? Where is the cut wire supposed to go?
 

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Hate to tell you this, but the points and condenser aren't behind the flywheel - they're on the driver's right side of the engine under a ~1"x3" cover above where the throttle and choke cables are held down. Only the stator (for charging the battery) is under the flywheel.

Regarding the cut wire, on replacement magneto (non-point) armatures the part is supplied with two "kill" wires with different terminations; the instructions state that one wire should be cut off and taped over. A points armature would have equal space between the legs whereas a magneto armature would be lopsided. If it is lopsided the points are irrelevant.

Here's a manual for a Briggs 320420 series like I'm assuming you have:
http://www.odref.com/briggsandstratton/model-32/320400-ms5868-1079.pdf
 

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Just a side not that will be helpful in the future. WD40 is not a lubricant or penetrating oil. The "WD" stands for "water displacement". I'm amazed that so many people use WD40 as a lubricant. If you want a good penetrant use PB Blaster. You will get much better results. Just a little FYI.

Good luck with your 990. I just picked up one last weekend and am very anxious to get it running.
 

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MTD 990 Twactor Guy
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574 Posts
Discussion Starter #4
Chagrin, Tiger -

Thanks much for the help on this!

Checked the side of the engine - yup - there's the cover. I'll pop it open in the morning and check out the points. Still have to finish getting the rust off the flywheel. Thanks for the info on the kill wire - I'll tape it back up. My Briggs is a 326400 series, but the link is a great help. Tiger - yes, you're 100% right on the WD - it's not really a penetrant, and I do have the PB Blaster - don't know why I didn't grab it. Oh well, I'm getting closer to getting this beastie running again.

It is a good thing that I took the front shroud off the engine :eek:mg: there was a huge mouse nest in there! Got it all cleaned out. It should run a little cooler now - LOL.

Again, thanks much! :thanku:

Rich
 

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Not sure you fully grasped what I was saying, SammyRye.

Your engine uses points if your coil looks like this:

Notice it has the same amount of space between the inner coil and the two legs.

Your engine does not use points if your coil looks like this:

Notice the there's no space between the inner coil and the right leg (actually the picture is showing the cylinder side of the armature here so the picture is backwards from how it would be mounted). The OEM Briggs part ships with a wire harness with two small black wires; the instructions tell you to cut off and tape over the irrelevant wire, and that sounds a lot like what you're describing. The previous owner may have already replaced the points armature on your engine, and if that is the case, messing with the points isn't going to do you any good at all.
 

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MTD 990 Twactor Guy
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574 Posts
Discussion Starter #7
Chagrin,

Thanks for the photos. My coil looks like the bottom one, so I'm assuming no points to look for. I didn't find any on the side of the engine anyway. Whew! I'm assuming I need to make sure the flywheel is rust free and that should solve my spark problems, unless the coil is bad. If I still don't have any spark, can I assume my coil is bad?

Liked the photo of the mouse nest - looked just about like mine. What a mess. :thanku:

Rich
 

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"I'm assuming I need to make sure the flywheel is rust free and that should solve my spark problems, unless the coil is bad. If I still don't have any spark, can I assume my coil is bad?"

No, Disconnect the wire running to the spade connection in the bottom picture on the left side. That is the kill wire. Now try the engine. IF no spark now most
likely the coil is bad but might want to clean the area where the coil mounts good first, bright, shinny contact area.

By the way, a little rust on a flywheel or coil laminations do not interfere with the magnetic flux required to produce ignition, it is a "fell good" thing to clean them.

Walt Conner
 
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