Mower no start

[Bertrrr]

You should have 12 volts at one of the large terminals on the solenoid all the time. Use a screw driver or pliers to short that terminal to the other large terminal on the solenoid. If the starter is ok it will engage, if it doesn't it's bad , pull the starter and bench test with jumper cables. - Hold it tight b/c it will jump off the bench when it engages with no load. You can move forward with anything else once you prove your starter

 

[noquacks]

Electricity travels in a circle
From the battery to the mower then back to the battery again
so using your car / truck run jumpers from the - to the engine ( sump plug is good ) and from the + to the starter post
If the starter is good engine will crank
If key is on and the circuits are good then mower should start .
If no then the starter is the problem .
IF yes then shift the + jumper to the starter side of the solenoid
Engine cranks = cable is good
If yes then shift to the battery side & turn the key
Engine cranks = mower electrics are good but battery or battery leads are bad .
Now try the same with your mowers battery
If it cranks normally in all tests, then remove the - lead
If nothing works properly then bad ground wire or connection
If it only works with the + jumper on the battery side of the solenoid then the power cable is bad .

I did the check above, line 3 and 4, and the starter did not turn at all. Not even a crank/noise. But, I unbolted the 4 bolts from the starter, and bench tested it, and it turned with 12 V. Why??? Maybe brushes are worn but enough to turn WITHOUT a load, I dunno.

Also, the test I did on the solenoid (which is 6 years old) failed. No V on the far end of the solenoid terminal. S I guess that is bad as well. Funny- 2 things are bad at the same time(?). I guess it can happen.

Anyway, a solenoid is cheap, so I will get a new one. Meanwhile, I should look into rebuilding the starter, at least have a shop check it out. Anyway, opinions on my detective work appreciated as always, as I know this is not over.

 

[Bertrrr]

If your starter engages and spins freely with no load ,it's most probably still good.your solenoid is the issue for sure

 

[shadetree#1]

Make sure the bendix teeth on the starter are en-gauging the flywheel teeth properly.
(sometimes the starter bendix teeth won't en-gauge (mate) with the Flywheel teeth properly and the starter will lock)

As a test take the starter cable wire loose from the solenoid (relay thingy as you called it in your first post) and take jumper cables to a 12v auto battery and connect to the cable with the pos jumper cable and make the last connection to the FRAME of the mower. This test gives you 12v direct connection to the starter.

Also if you keep on making arcing connection to the starter's 12v post you are going to ruin the threads on the copper starter stud.

Let us know the results????
We need to get it cranking good before we get into getting it to run.

What is the model and code of your Tecumseh?

 

[smalltimerpm]

still focusing on starter here when he said he got it to turn over once and then bench tested it. But yet on the mower he gets nothing at all?even a weak starter will click. Maybe need more specifics! Please. And like before maybe check power and make sure you are getting 12v from ignition wire to solenoid every time with key in start position.

 

[smalltimerpm]

Still alot to determine and check

 

[smalltimerpm]

Maybe check the whole thread

 

[Ronni]

People,

1998 MTD rider, with tecumseh engine, battery shows 12+ volts, but no start. So I tried bypassing the key switch and jumped it directly from the relay thingy (just under, in front of the seat) to the bolt/nut on the starter motor. I got it to turn but never started. tried started fluid, no start. Afraid to drain the battery.

Then I tried a car battery directly to the battery terminal, and no reaction/turning over at all. Lastly, I touched the bolt on the starter directly from the pos terminal from the car battery, nothing at all. But when I jumped from the hot (red) wire of the solenoid to the starter it turns over. I took voltage on that solenoid with switch on and no voltage. Gotta be a bad solenoid, right? Meanwhile, even when I jump it and engine turns, it doesnt start. There is gas in the float bowl.

The mower has not been started for at least 4 months.

Thanks, people.

I had a similar problem; I ended up replacing the starter solenoid and the starter motor because both were old and that solved my problem.

 

[Smithsonite]

If these sit outdoors, you can get a situation where the ground between the starter and the engine becomes poor. Doesn't happen often, but that would explain why it spun on the bench but not bolted to the engine. The brushes can also get oxidized, and the bushings for the armature can dry up, too. Sometimes a sharp whack will get them turning. Most would just replace the starter, but I take them apart, free things up, sand the armature & brushes, grease the bushings and it's good to go. Anything built in the 21st century, particularly after 2005, your chances of success drop, however.

12.45v isn't super bad, but it isn't good either. I'd rather see 12.65 or higher. In 30° temps, 12.45v is probably fine.

If the starter sounds like it's binding against compression, you might need a valve adjustment. The compression release is dependent upon proper valve clearance. I've had many a machine that couldn't crank past the compression stroke, and smoked the battery / melted wiring. Valve adjustment fixed that.

If it didn't pop on ether with good spark, then I'm leaning to a compression / valve problem, or a sheared key that threw ignition timing off.

 

[elmrfudd]

I had a similar situation once, and found that I had lost a good ground connection where the solenoid mounts to the frame. I ran a new ground wire from the solenoid to another area of the frame, and it cranked over perfectly. So check to make sure your solenoid body itself is well grounded. You can also remove the solenoid, wire brush the mounting area, and reinstall.