No spark B&S Intek 205cc

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5,722
Location
Charlotte, NC
Motor is over 10 years old. Has not been run for ~3 years. Always run perfectly. Got it out of storage and and no start. A quick check indicates no spark. Has a nearly new plug, installed shortly before it was laid up. Tested the grounding wire at the kill switch, switch is good, the wire reads 5.7 ohms to ground. I think this is reading resistance through the coil, but my question is, is this a good test, and if so, what should the # be? I would like to pin this down before I order a new coil. This is the motor. I have a parts book and a repair book in my library, IE:in a box somewhere in storage. ??? Thought I would ask here first, maybe someone knows the answer.
Quote:
Sears Craftsman 7hp 19" Rear tine tiller Model # 917.293493 S/N B&S Intek Family 4BSXS.205HF 275160 Model ---Type ---Code 030410 --FD ---121402 0216 l1 Carb 215369 7297 0783
TIA Wayne.D
 

Oldmoparguy1

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Charlotte, NC
Originally Posted By: Chris Meutsch
Old fuel? Perhaps the commutator corroded up?
Fresh fuel. Everything has been cleaned and inspected. what is a commutator?
 
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MA, Mittelfranken.de
There should be infinite ohms going to ground when the switch is in the run position, it should be open. When the switch is in the stop position it should be close to zero. Disconnect the switch, pull the wire off the coil and try it. It sounds like a bad switch or dirty contacts. Edit: Look for little teeth marks on the wire that could allow it to run on metal.
 
Last edited:

MolaKule

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21,597
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Iowegia - USA
Originally Posted By: Trav
There should be infinite ohms going to ground when the switch is in the run position, it should be open. When the switch is in the stop position it should be close to zero. Disconnect the switch, pull the wire off the coil and try it. It sounds like a bad switch or dirty contacts. Edit: Look for little teeth marks on the wire that could allow it to run on metal.
thumbsup Trav said what I was thinking. It's usually the coil kill wire being grounded via corrosion, mud, wasp nests, etc.
 
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Pittsburgh,PA U.S.A.
Check that the low oil shut-down switch is not grounding out the ignition: Measure the resistance of the on-off switch to ground on the side of the switch that is NOT connected to ground, when the switch is in the run position. It should be very high resistance. If it is connected to ground disconnect the wire from the low oil shut-down switch and measure it again.
 

Oldmoparguy1

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Charlotte, NC
Originally Posted By: Chris Meutsch
https://en.wikipedia.org/wiki/Commutator_(electric) It's the part that creates spark.
Umm, No. These little engines use an electronic ignition module, integrated in the coil unit. You may be thinking of another kind of motor.
 

Oldmoparguy1

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5,722
Location
Charlotte, NC
Originally Posted By: Trav
There should be infinite ohms going to ground when the switch is in the run position, it should be open. When the switch is in the stop position it should be close to zero. Disconnect the switch, pull the wire off the coil and try it. It sounds like a bad switch or dirty contacts. Edit: Look for little teeth marks on the wire that could allow it to run on metal.
Did all that. Looks like I have to take off the gas tank, cooling shroud and whatever else to get to the mag. If the wire is good, looks like it's a new coil. Bother. Thanks Trav. Thanks Pop for the link.
 

Oldmoparguy1

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5,722
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Charlotte, NC
Originally Posted By: FastLane
Take the plug out and keep it attached to the ignition wire. Ground the plug to the block. Pull it over. Does it spark?
No...
 

Oldmoparguy1

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5,722
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Charlotte, NC
Originally Posted By: FastLane
Has to be the ignition coil. My Tecumseh on the snow blower has to have the magnets cleaned off every few years. Might be worth a shot.
Yup. Tore it down yesterday, the kill pin on the coil is ~5 ohms to ground. New one on the way, $18 from Amazon. Actually, it was a good thing I did tear it down. Lot of dirt inside, the shroud was rusty. Will clean every thing up and paint the shroud.
 

Oldmoparguy1

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5,722
Location
Charlotte, NC
Originally Posted By: Oldmoparguy1
Originally Posted By: FastLane
Has to be the ignition coil. My Tecumseh on the snow blower has to have the magnets cleaned off every few years. Might be worth a shot.
Yup. Tore it down yesterday, the kill pin on the coil is ~5 ohms to ground. New one on the way, $18 from Amazon. Actually, it was a good thing I did tear it down. Lot of dirt inside, the shroud was rusty. Will clean every thing up and paint the shroud.
Foo... New coil, same problem.. Spent over 2 hours on the internet chasing every hit for this problem, Found a u tube video on how to test the coil. My new coil measures the same as the one in the video. My old coil measures the same also. 10k to ground on the secondary, 2 ohms to ground on the primary. There were a good number of hits for this exact problem. Tried all the fixes, No joy. Now what?
 
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750
Location
Nebraska
Is that the engine that has the exhaust running right by the coil? I get bad coils on those all the time because if just a little grass and debris gets around the coil, it gets stupid hot. Blown head gaskets on that engine too.
 
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304
Location
Maryland
Did you check for spark between the coil wire and ground without the spark plug? Did you set the correct gap between the armature-magneto (coil) and the flywheel (it's critical) I had a similar problem last year with my B&S powered lawn tractor, and turned out to be a bad spark plug and too much gap between the armature-magneto and flywheel. Good luck!
 

Oldmoparguy1

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5,722
Location
Charlotte, NC
Originally Posted By: chemman
Did you check for spark between the coil wire and ground without the spark plug? Did you set the correct gap between the armature-magneto (coil) and the flywheel (it's critical) I had a similar problem last year with my B&S powered lawn tractor, and turned out to be a bad spark plug and too much gap between the armature-magneto and flywheel. Good luck!
Tried a new plug. Old plug was nearly clean with white center piece. Only an hour or so on it. Put the old plug in my rider to test. Worked fine. Cleaned the flywheel of rust and polished the magnet with 320 wet or dry paper and wd40 for lube. Set the gap to .010. later tried .008. No change. I've been working on these B&S motors for 65 years. Never before have I found one I can't fix. Don't know what to do next. Frustrating. I may have to go to Harbor Freight and buy a new chandra 212. They are on sale this week.
 
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