Hey guys, I could use some help troubleshooting my Craftsman riding mower. As you can see from below it won't turn over. I'm thinking there's an issue with the ring gear. The battery is fully charged and a new fuse and starter motor have been installed. Any help would be greatly appreciated!
Post model number from under seat, engine manufacturer & all numbers from engine. Check oil level, remove spark plugs & try rotating engine by hand top of engine screen.
Thanks for the reply Mark. Its a Briggs & Stratton Engine 28N707. 917.259830 is the model of the mower. The oil is good to go and I've rotated the engine by hand using the engine screen. It's relatively easy to turn, with some weight to it. The spark plug is about a year old.
That looks like a new starter motor with the wrong starter gear.
There are 3 different ones and each one has a different number of teeth.
The raw plastic gear goes on alloy and plastic ring gears
The metal cased gear goes on flywheels with iron teeth like yours.
Check this by removing the spark plug & rolling the starter gear up till it engages with the flywheel.
Mark the contact tooth on the starter gear with a marking pen now turn the engine backwards slowly.
Chances are after 4 or 5 teeth have gone through they will no longer line up, thus lock.
Just about every cheap starter on the web has the plastic gears on it because they are $ 1 each while the metal ones are $ 9 ( OZ wholesale prices ).
Now why were you replacing the starter in the first place and do you still have the old one ?
Thanks Bert. That's an interesting test I'll have to try. I replaced the starter because the old one was in visibly bad shape, e.g. the metal mounted to the motor where the positive connector goes was lose. The starter pinion gear is made of cast iron. I actually bought the part from the manufacturer (Sears Parts Direct) because as you mentioned many of the lower priced motors are equipped with plastic gears. It's definitely worth paying extra to ensure the part will be compatible.
I spoke with Dave earlier and I'm going to work on adjusting the valves. Right now I'm researching methods on how to carry out that adjustment and what tools I need, such as a feeler gauge and torque wrench.
I don't think the pinion ( gear that turns the flywheel ) is cast iron.
There is a 16 tooth plastic gear
There is a 14 tooth aluminium coated plastic gear
There is a 15 tooth steel gear ,
All have the same spiral so they will fit on any starter motor.
I do not know of any others but I am happy to learn if any one knows different.
Odd, the sales reps I spoke with assured me its a cast iron alloy. I specifically asked to make sure. If it's not, I will definitely ask for a refund and file a complaint for the misinformation. I've attached images of the motor and gear above. Thanks Bert.
The flywheel is cast iron the gear on your starter motor is definately not.
I am just a mug repairer not a B & S certified master technician.
There are a few of them on here but as far as I know there is no iron starter gear and the steel gear is only used on Vanguard engines but as always I am happy to be proven wrong, that is one way we learn.
I have stuffed up enough starter gears to recognise a gear lock when I see one which is why I suggested you test the meshing of the gears.
There are a few other things that will stop the engine dead like that, but all of them will also stop the engine when you try to rotate it by hand as well.
Bert, you were absolutely right. There was a mix up with the part number and the gear is plastic. "This is a manufacturer substitution. Part may differ in appearance but is a functional equivalent to prior parts including 280104."
I ran the test you suggested Bert. I was able to rotate the flywheel with both hands, at a reasonably quick pace, for an average close to 15 seconds before it would lock. Once locked, no matter how hard I tried to turn it, it wouldn’t move. A few times I was able to turn it for around 30 seconds straight. However, each time it would lock, it would lock at the same spot. I’ve included several pictures that show what the ring gear teeth look like around that area. You can see where I marked the flywheel for reference. I've also included two pics that show what the teeth look like from the other side.
