Help finding magneto for craftsman rife on mower

[305]

That makes perfect sense. I will disconnect the ground after use over the next few days and see what happens.

I was thinking it was not charging at first because the head lights would get bright or dim depending on the engine rpm. Then I realized that is how it works with this type of charging system. I had a mini-bike me and my father built when I was a kid and it had a briggs and the head light would do the exact same thing especially when the magneto gap was not right.

Thank you for the help. I will report back Monday and let you know what I found.

 

[ILENGINE]

From one of your pictures it looks like that engine has the 3/5 charging system. 3 amp half wave unregulated to DC and 5 amp AC for headlights.

 

[305]

Honestly I don't know enough about the mower to confirm if it's 3/5 charging system. I can say the headlight bulbs are good from what my multimeter says but they do not turn on. There is one brown wire that is always hot and there are 2 black wires that are hot or at 0v depending on the position of the headlight switch. The 2 black wire are connected together. If I seperate them the starter won't turn. When they are connected together the mower starts fine. The brown wire isn't connected to anything.

 

[305]

I forgot to mention you were totally correct about the choke not closing all the way. I fixed that and it starts right up until the battery discharges.

 

[LMPPLUS]

Question, have checked the voltage coming out of the stator / alternator and out of the voltage regulator?

 

[Freddie21]

You could also run the battery to an auto supply store when it's fully charged for a free test.

 

[VRR.DYNDNS>BIZ]

Hi.
I can't figure out what magneto I need for my craftsman yts3000 ride on mower.
Model 917.289140
21hp briggs platinum xrd engine #143.008501

I believe it's made by Tecumseh but there are no labels saying so. The research I've done trying to find the correct part and part number has only led to more confusion. There are so many out there I have no clue what to order.

As always thank you. The info I've gotten from you pros who know way more than me has been invaluable.

143.008501 HM85-155851B Tecumseh
the conversion can be found on my website page: http://vrr.dyndns.biz/Docs/Repair/linecard.html under sears.

 

[VRR.DYNDNS>BIZ]

Model: 331877 or l33L877
Type code1449 61 100309zd

I don't think it needs a magneto. I put the meter on it while running and it's charging like it should. The issue is the battery will loose cranking amps after a couple of days and it won't start the mower unless I jump or recharge it. The battery is 3 months old but it's seen alot of cranking the starter with a no start condition. That has been fixed. Question.

Could I have killed the battery by trying to start it when it won't start?
Could it be solenoid and how do I test the solenoid?


When the battery is fully charged the mower starts up on the second or third cycle. What am I missing here?

Battery, cables, starter or valve adjustment. If valves have not been adjusted and have worn .002" loser than original, the decompression is not going to work, the starter and battery cannot withstand the additional compression and it acts like battery or starter or discharge more than can charge on a short run time.

 

[wheelie]

Just to throw this in.. On my 21 horse Briggs I have lost the compression release on the cam.. When I have a battery charger on the battery or have had one on in the last 12 hours approx. or less it starts fine.. After setting with no charging for more than the 12 approx. hours there is enough battery drain off (top charge) that the engine will turn over slow and usually hang (lock up) at the decompression stroke.. It took many battery changes including known good batteries from other equipment and a couple new batteries and then an accidental reading explaining about the compression release issue. I have been running said mower for a couple years or so this way but if I try to start it after the battery has set without a charger on it for much time I have to be prepared to take my wrench and turn the crank backwards.. It will start almost every time then with same said battery.

 

[VRR.DYNDNS>BIZ]

Just to throw this in.. On my 21 horse Briggs I have lost the compression release on the cam.. When I have a battery charger on the battery or have had one on in the last 12 hours approx. or less it starts fine.. After setting with no charging for more than the 12 approx. hours there is enough battery drain off (top charge) that the engine will turn over slow and usually hang (lock up) at the decompression stroke.. It took many battery changes including known good batteries from other equipment and a couple new batteries and then an accidental reading explaining about the compression release issue. I have been running said mower for a couple years or so this way but if I try to start it after the battery has set without a charger on it for much time I have to be prepared to take my wrench and turn the crank backwards.. It will start almost every time then with same said battery.

What you describe is a very common outcome. The starter doing more than designed to do, instead of 80-100 amps is cranking slow and less spark as a result and drawing 200-300 amps. It leads every one to think it is a failing starter. Eventually it is and replaced, but does not solve the problem. This is often after a battery or two. I do have to add that there are two types of decompression cams, a third lobe before TDC that lifts the valve slightly and at cranking speed relieves compression. A second design has a centrifugal attachment to one cam lobe which can fail. Both require proper valve adjustment, but when that is done and the mechanical decompression has failed, a new cam is required.