MTD 990 engine driving me nuts!

I've got an MTD 990 with the original 16hp Briggs L-head engine. I can't get the engine to fire at all. It has a new coil and spark plug making spark, 100+ lbs compression, flywheel key is fine, and as I crank the engine, I'm spraying carb cleaner into the air intake. The fuel line isn't connected, but shouldn't it pop anyway? What am I missing? Oh, and the new coil is a Magnetron style, so I am bypassing the points and connecting the ground wire right to the kill wire from the switch. Can anyone help me with a new idea?[/quote]

Leave the kill wire disconnected from the coil and see if it starts. If you have compression and spark at the sparkplugs, it should at least try to fire on the carb cleaner.

a bad or flakey kill switch can give you problems, or a pinched wire under the shrouds. disconnecting the Kill wire from the coil itself eliminates all that. but, keep in mind, if the engine does start, the switch won't shut it off. you'll have to choke it or stall it.

With a magnetron coil, you will have spark even with a sheared flywheel key. it just occurs at the wrong time.

Is this engine a 16 HP single cylinder or a 16 HP Flat Twin? If it is a single cylinder, there is a code number break on the usability of the Magnetron coils on these engines.

Kent

This information was received in 2005.You might want to check before shipping. My engine would start easier if I held the throttle plate closed
while cranking.


Jack,

Thank you for your inquiry.

The post is correct. The electronic ignition does not work well in conjunction with the existing polarity in these engines’ flywheels. Typically this happens on older (1981 and older) horizontal shaft cast iron engines with model numbers beginning in 23, 24, 30 and 32.

If you have one of these engine models and wish to install an ignition kit, we will re-polarize your flywheel and send it back to you, free of charge.

When shipping your flywheel, package it properly (we have received several of these already broken from shipment because they were not packaged properly), with a short note describing what you need, the Model, Type and Code of the engine, and a return address.

Send to:

Briggs & Stratton Corp.
Menomonee Falls Distribution Center
FLYWHEEL REPOLARIZATION
W148 N9121 Patrita Dr. (Dock 23)
Menomonee Falls, WI 53051 2272

Please keep in mind, we CANNOT return ship to a PO BOX (we need an actual address to ship to).

If you have any further questions, feel free to update this e-mail.

Sincerely,
Mike
Briggs & Stratton
eCustomer Support Representative

try putting some gas in the intake. i never had one fire on carb cleaner yet in fact if you have a running motor and spray it with carb cleaner it will kill the motor

Post the engine model number & spec number. Hal

Try gas or a small amount of starting fluid. Carb cleaner will kill an engine that is running, so it will not fire when trying to start.

Thanks for all the tips! The ether was a no-go as well. The flywheel repolarization sounds like my best bet, and since I'm only out freight, I'm going to try that before anything else drastic.

To reply to the other answers, I did try to start with the kill wire disconnected. No luck. And I had physically looked at the flywheel key, that's why I said it was fine.

It's a single cylinder, L-head, model 326431 spec 0228, 1977 model year by the serial, so yes, it sounds like the magnetron is incompatible unless I get the flywheel repolarized.

Thanks for all the great responses! There were more answers than I might have expected. It is much appreciated, and I will report back if the flywheel takes care of the problem.

Touch those magnets with a flatblade screwdriver and see if they have strong magnetism. You can install an auto type coil using the old points and condenser. You would need to run battery voltage to an ignition switch, from the switch
to the plus terminal on the coil and from the neg post to your points. Disconnect the old wire from the old armature at the points. Hal

The points should be installed externally on the engine block. Would cost a good bit to ship the flywheel. Hal

Two weeks later, here is my update. I sent the flywheel to Briggs for repolarization on a Wednesday, got it back that Friday, and put it together Saturday. She now purrs like a kitten! Well worth the $10 in shipping! After all of my frustration, I can't believe it was something so relatively simple. Now she's ready to go back to the garden for rototilling and cultivating, and I can start some of those projects for tools I want to build for it. Thanks for all the replies, you guys are great!