John Deere 125 -w- 20 HP B&S V Twin / Ignition

[Logan Savage]

I have a John Deere 125 lawn tractor with a 20 HP Briggs & Stratton V Twin engine . I just bought this mower used late last fall . I was using it for about the third time this spring when I noticed a difference in the tone of the engine . It wasn't making any rattling or knocking noises just sounded different so I continued using it this summer . I did adjust the valves which really didn't need much adjustment . This fall I began having starting problems . It always cranks over fine but sometimes it started right up & sometimes it wouldn't hit a lick . When it wouldn't start usually go out the next day & it would fire right up .
I decided to check the plugs & in the process found one of the spark plug wires wasn't sparking . After I did a little research I took an ohm reading on that coil & with my digital meter set on 20K ohms the coil read 4.2 . One day it wouldn't start & I found that neither spark plug wire had spark . Using the same setting on my meter I took a reading on that coil & it read 4.6 . I had disconnected the black kill wires & still no spark .
I have another mower with a 17 HP engine & I checked the coil on it & it read 4.5 & was running till it bent push rods & I parked it . From what I've read the only things that will cause no spark is either a bad coil or bad magnet on the flywheel assuming the spark plug wire itself is good & the ground / kill wires are disconnected . With the flywheel on the engine I can lay a large screwdriver end against the magnet & it will hold it straight up so I'm assuming the magnet is good .
I'm now assuming the change in the tone of the engine back in the spring was when the first coil stopped firing & the later starting problems began when the second coil began to fail . Is it unusual for coils to fail & cause the problems I have described & what are your thoughts about the ohm readings on the three different coils ? Are replacement flywheel magnets available or does the flywheel have to be replaced if the magnet fails ? Thanks in advance .

 

[mechanic mark]

Post your model xxxxxx, type xxxx trim xx from engine. Thanks

 

[Logan Savage]

Post your model xxxxxx, type xxxx trim xx from engine. Thanks

Engine model # is 441577 Type # is 0113E1 Code # is 060227YG

 

[mechanic mark]

Results Just information, your engine manual.

Amazon.com : BRIGGS AND STRATTON 273521 REP MAN-INTK V2 OHV : Four Stroke Power Tool Engines : Patio, Lawn & Garden Your engine repair manual.

OMGX21821_H5 check out troubleshooting section

Hands on, inspect everything electrical as well as all connections including ignition switch, all switches & relays, making sure everything is secure and tight including ground straps & cables. Check for corrosion, rust, bare wires etc. Let us know what you find, thanks.

 

[motoman]

logan, If you search the forum you will see my soap box speeches on the subject of coils. The resistance check is not a thorough check of the coil. I'm on shaky ground here, as I only run a 2004 Intek. But recently forum people have referenced some Briggs info online and I have also seen some. Inside the (Magnetron) coil are two power transistors which charge and amplify the spark signal . As such they cannot be tested (long story and not for this forum although info is availabe on line). So the VOM may check for "opens" in the cables or maybe in some windings ,but it cannot tell you if the transistors are still alive. IMO the best grade of transistor will die at around 250F. Do not know what grade Briggs uses (commercial, industrial, military). The modules sit on big chunks of iron near fan wind so probably stay cool and live long lives. Battery voltage applied will snuff them right out. Supposedy dealers have module testers. Becareful with bat voltage. Several forum members have executed the modules without good reason.:smile:

 

[Logan Savage]

logan, If you search the forum you will see my soap box speeches on the subject of coils. The resistance check is not a thorough check of the coil. I'm on shaky ground here, as I only run a 2004 Intek. But recently forum people have referenced some Briggs info online and I have also seen some. Inside the (Magnetron) coil are two power transistors which charge and amplify the spark signal . As such they cannot be tested (long story and not for this forum although info is availabe on line). So the VOM may check for "opens" in the cables or maybe in some windings ,but it cannot tell you if the transistors are still alive. IMO the best grade of transistor will die at around 250F. Do not know what grade Briggs uses (commercial, industrial, military). The modules sit on big chunks of iron near fan wind so probably stay cool and live long lives. Battery voltage applied will snuff them right out. Supposedy dealers have module testers. Becareful with bat voltage. Several forum members have executed the modules without good reason.:smile:

Thanks for replying , I have decided to order two new coils . If I don't have spark after that I'll order a new flywheel . The magnet on my flywheel looks replaceable but I can't find any so maybe not . To eliminate the possibility of voltage on the kill wires I'm seriously considering running them to a toggle switch that has the other leg connected to ground . I suppose this will defeat safety switches but no one uses this mower but me . I will probably run the kill wire through the seat switch also . Any words of wisdom concerning this will be appreciated .