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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 12726
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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wheel horse tractor 520h onan 20 hp engine cranks but will

Customer Question

wheel horse tractor 520h onan 20 hp engine cranks but will not start checked plugs coil stantor switcher ignition control all safey switces gets pleny of gas
Submitted: 7 years ago.
Category: Small Engine
Expert:  Hank F. replied 7 years ago.
<p>Hello,</p><p>What is the full model number of the engine?</p><p> </p><p>Is it getting fire at the spark plugs?</p>
Customer: replied 7 years ago.
no spark at plugs
Expert:  Hank F. replied 7 years ago.
Does your engine have the 4 pin connector or the 6 pin connector?

When you checked the coil and stator, how did you test them and what results did you get?

Are you getting 12V to the positive terminal of the coil while cranking?
Customer: replied 7 years ago.
6 pin checked to mak sure tight checked with volt meter dont remember values but comparded them with the values with toros specs for the onan engine
Expert:  Hank F. replied 7 years ago.
<p>OK</p><p> </p><p>1. Did the engine just quit, or did you have it taken apart for some reason?</p><p> </p><p>2. Teh ignition coils each have a black wire coming out of them that go to a small unit called a stop diode. Disconnect both black wires from the diode and try to start the engine. Do you have spark now?</p>
Customer: replied 7 years ago.
engine exhaust value robore and reseated just got it back from the shop and put it in today engine was running when it was taken in to the shop engine turns over but will not start
Expert:  Hank F. replied 7 years ago.
<p>OK</p><p>A head job should have nothing to do with it not getting spark all of a sudden.</p><p>The ignition coils each have a black wire coming out of them that go to a small unit called a stop diode. Disconnect both black wires from the diode and try to start the engine. Do you have spark now?</p>
Customer: replied 7 years ago.
where are the 2 wires located that go to the small stop diode and where is the small diode at
Expert:  Hank F. replied 7 years ago.
<p>The 2 wires are the black wires that come off the ignition coils. They will look like they come out of the engine itself, from under he flywheel. </p><p>I do not know where put the diode at. It will have 3 wires attached to it, and all 3 wires will be black.</p><p>There will be a relay, probably in front of the dash, that will have a white and a black and 2 other ground wires (either black or green). This black wire will also lead to the stop diode.</p>
Customer: replied 7 years ago.
what do i need to remove to acess the the ignition coil all so to acess the stantor and ignition control is the relay in the front dash or behind the engine
Expert:  Hank F. replied 7 years ago.
<p>The relay was installed by Toro, so I can not say for sure where it is, but they are usually in front of the dash area, behind the engine. It may be on the engine.</p><p>To access the coils and magneto, you will need to remove the flywheel, as they are mounted underneath it.</p>
Expert:  Hank F. replied 7 years ago.

Another way to find the stop diode is to find the low oil pressure switch. It will be the sensor mounted next to the oil filter. There will be 3 wires on this switch - red, white and blue.

Follow the white wire back to the relay, then follow the black wire back to the stop diode.