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Hola,

I am a newbie to this forum but not to small engine repair and I hope to be able to help out when I can.

I am SO happy to find this forum and after browsing some related threads I found nothing to help me so I have to ask a question.

I bought a 8241 AE self propelled electric start. The previous owner said he just used a drill motor on the top nut on the crank shaft to start this but I would like to do a proper job if it doesn't cost me an arm and a leg.

The starter I took it apart and used contact cleaner and various other things to get it clean and then a little bit of machine oil on the bearings. I put it back together and it will turn now but it will not start turning on its own you have to grip the shaft and spin it a bit and then it will take right off.

Even if i hook it directly to a 12v car battery it will not start on its own.

Is there a capacitor anywhere in this circuit? I see there is a relay but that seems to work fine I hear it click but still I have to spin the starter to get it going.

Any help on this issue is greatly appreciated

John

Hi John,

I don't see a capacitor in any of my Lawn-Boy electrical wiring diagrams but some models did use a solenoid. Have you check the armature of the electric starter motor to see if one of the wirings has a short in it?

Jeff

I am not familiar with the electric start motor on lawnboy, but can offer some generalities. You say you had it apart and cleaned and lubricated... Does this starter have the magnets around the case and an armature that goes through the middle with brushes and a commutator?

It has been my finding, that sometimes when they don't spin proper or have any torque, that the unit may have cracked magnet and that changes the whole dynamic on that type of starter. As long as the armature doesn't have any open (or shorted) traces, the brushes are in tact and making good contact, and the bearing are spinning freely, then you might inspect the magnet material.

You can polish the commutator with a little scotchbrite or fine sandpaper (400,1000) and clean the sections between the segments maybe with a pick or even maybe a fine blade. Check continuity/resistance from side to side (where the brushes would touch the commutator if assembled) and also check for continuity to ground or to other segments.

Take it to an electric motor or starter shop for evaluation...
Cheers!

Also,
Check your open circuit voltage (battery voltage) (i know you said you tried it with a jump start car battery) but then also, monitor the voltage at the starter terminal when you try to crank it. It should drop off some, but I don't believe it should fall to more than 10-11 volts when cranking) If it does, there may be resistance in the solenoid or on boats it is common to have a corroded wire that lets trace voltage through (shows 12 volts) but drops down to little when actually trying to do the work.

Maybe do the cranking voltage at the starter test with and without the 12 volt jump start.

Found this
$36.50 to your door. Or $419 new.

http://www.ebay.com/itm/Lawn-Boy-10...006c781&pid=100005&rk=2&rkt=6&sd=252490700021

You need to determine what the fault is before you start just throwing parts at it though... But for $40 it might just be worth having a spare starter.
You could also be able to just put a manual pull starter on it too.

I recognize the plug as a trailer wiring type plug that you can get at Napa. What happens when you just connect the starter direct to a battery without a load on it?
It is also a good idea to run a motor without a load on it to let the brushes wear to the commutator (don't let it overheat)

When you reassembled it, did the brushes go back in the same holder they came out of? There can be minor differences of alignment that may not have them making full contact.

A good power source to use is a 18volt battery out of a cordless drill, just need some alligator clips and a volt meter to find the two leads on the battery.

Yes it is as you describe the magnets are stationary in the outer steel case

since it does spin with a help to start I do not suspect any open condition on the commutator but I will check that anyway

thanks!

fabricgator said:

I am not familiar with the electric start motor on lawnboy, but can offer some generalities. You say you had it apart and cleaned and lubricated... Does this starter have the magnets around the case and an armature that goes through the middle with brushes and a commutator?

It has been my finding, that sometimes when they don't spin proper or have any torque, that the unit may have cracked magnet and that changes the whole dynamic on that type of starter. As long as the armature doesn't have any open (or shorted) traces, the brushes are in tact and making good contact, and the bearing are spinning freely, then you might inspect the magnet material.

You can polish the commutator with a little scotchbrite or fine sandpaper (400,1000) and clean the sections between the segments maybe with a pick or even maybe a fine blade. Check continuity/resistance from side to side (where the brushes would touch the commutator if assembled) and also check for continuity to ground or to other segments.

Take it to an electric motor or starter shop for evaluation...
Cheers!

Click to expand...

might give that a try but I had the motor and leads right at my car battery and with 600+ amps at 13volts i would think that would be more than enough persuasion!

thanks for commenting!

J

fabricgator said:

Also,
Check your open circuit voltage (battery voltage) (i know you said you tried it with a jump start car battery) but then also, monitor the voltage at the starter terminal when you try to crank it. It should drop off some, but I don't believe it should fall to more than 10-11 volts when cranking) If it does, there may be resistance in the solenoid or on boats it is common to have a corroded wire that lets trace voltage through (shows 12 volts) but drops down to little when actually trying to do the work.

Maybe do the cranking voltage at the starter test with and without the 12 volt jump start.

Click to expand...

Actually looks like it is 22.50 and i am going to buy it! thanks for the link

I have the motor pulled NO Load at all and it will not self start when current is directly applied to it from my car battery. It will spin when I help it get going but the perfprmance is erratic and it varies seeds all on its own on occasion.

I cleaned the brushes with electrical contact cleaner and took scotchbrite to them as well as the commutator and the segments the windings go around

Something is amis with the motor so I tried my best to get it going. I can use the spare gears and bendix too


J

fabricgator said:

Found this
$36.50 to your door. Or $419 new.

http://www.ebay.com/itm/Lawn-Boy-10...006c781&pid=100005&rk=2&rkt=6&sd=252490700021

You need to determine what the fault is before you start just throwing parts at it though... But for $40 it might just be worth having a spare starter.
You could also be able to just put a manual pull starter on it too.

I recognize the plug as a trailer wiring type plug that you can get at Napa. What happens when you just connect the starter direct to a battery without a load on it?
It is also a good idea to run a motor without a load on it to let the brushes wear to the commutator (don't let it overheat)

When you reassembled it, did the brushes go back in the same holder they came out of? There can be minor differences of alignment that may not have them making full contact.

Click to expand...

do you meter each segment separately?

J

jp1961 said:

Hi John,

I don't see a capacitor in any of my Lawn-Boy electrical wiring diagrams but some models did use a solenoid. Have you check the armature of the electric starter motor to see if one of the wirings has a short in it?

Jeff

Click to expand...

Again, I'm not familiar with this particular motor.
Is there any possibility of the brush holder being out of position? Can it go together 180º out?
Imagine if you would, a kid learning to ride a bicycle. They have a tendency to put the pedal straight up, and when they push, it won't go until they get past center...
The motor work off of repulsion of the polarity of magnets, is it possible that once you get it off center then it runs?

When you get it turning, does it run strong? And like jmacster said, does every pair of segments have continuity or is there maybe a dead pair (a dead spot you have to overcome) and once turning, the momentum carries it past that dead spot?

Yeah $22.50 but I always quote and think about how much to my front door, so with shipping it is the better part of a couple of $20's bills... I'd get it if I were you. I'd also keep the old one for parts as this one ages. Over the years, I have spent thousands of dollars on storage for hundreds of dollars worth of junk...

I guess I did not understand that there are different segments that can be metered discretely! I have only done things like replace brushes , seals , bushings and bearing and motor mounts. I have not spent any time really working on a stator or armature. I will look into this aspect of it

I did get the replacement and although it looked worse than the one I have it works smooth, I swapped out the bendix as the one I had was in top shape

This is a nice mower now and I have it loaned out to a buddy that is basically disabled to the point that starting a mower is impossible and pushing one is bad for him too, so this battery start and self propelled is perfect for him!

That is a great thing you did there John,

A great opportunity for him to get some exercise within his ability and keeps the lawn groomed!

I am glad it worked out for you.