Toro pushmower

[mowerguy]

Have an older Toro push mower a neighbor dropped off the other day. He said it starts up no problem but if you shut it off after it's warm it's impossible to get started back up until it cools back down. Where do I start my diagnostics. He thought maybe ignition coil. Any help is greatly appreciated. I will post engines numbers soon as I am not home now. Do know it has a Briggs on it. Thanks in advance!

 

[lzn197]

You start with checking to see if it has spark when it is hot. No spark, it probably is a coil. Second. Is it real easy to pull the starter cord when it is hot like poor compression? That would be tight valve clearance (valve expands when hot and is held open)

 

[Mower Doctor 78006]

I have had coils fail when the engine gets hot. I have also had people use the briggs intek gas cap on quantum push mower engine. One is vented and one is not. It will not restart if the wrong gas-cap is used. Try running and pull cap and see if it restarts. Easiest way to check coil pull gastank, and blower housing. Pull black ground wire from coil. Test run mower with full tank of gas. If it runs with no problems its the coil. Just remember to shut off use a pair of insulated pliers and pull spark plug boot from plug. If its the heat cycling problem when warm cylinder expands and won't build compression its cheaper to re-engine then rebuild.

Have an older Toro push mower a neighbor dropped off the other day. He said it starts up no problem but if you shut it off after it's warm it's impossible to get started back up until it cools back down. Where do I start my diagnostics. He thought maybe ignition coil. Any help is greatly appreciated. I will post engines numbers soon as I am not home now. Do know it has a Briggs on it. Thanks in advance!

 

[lzn197]

Easiest way to check coil pull gastank, and blower housing. Pull black ground wire from coil. Test run mower with full tank of gas. If it runs with no problems its the coil. Just remember to shut off use a pair of insulated pliers and pull spark plug boot from plug. If its the heat cycling problem when warm cylinder expands and won't build compression its cheaper to re-engine then rebuild.

I am not understanding this comment. Could you please explain further? I'm reading it as running the engine WITHOUT a cooling shroud for several minutes (full tank of gas)?

 

[Mower Doctor 78006]

No. It was an explanation of testing the coil. Remove gas-tank, pull starter housing, pull black coil wire. Reinstall starter housing, re install gas-tank. Test run with black coil wire/Coil ground pulled. If it runs great. Doesn't shut off till out of fuel. Bad coil.

I am not understanding this comment. Could you please explain further? I'm reading it as running the engine WITHOUT a cooling shroud for several minutes (full tank of gas)?

 

[Fish]

If it doesn't shut off until out of fuel, how is the coil bad?

 

[lzn197]

No. It was an explanation of testing the coil. Remove gas-tank, pull starter housing, pull black coil wire. Reinstall starter housing, re install gas-tank. Test run with black coil wire/Coil ground pulled. If it runs great. Doesn't shut off till out of fuel. Bad coil.

Huh? How can that prove the coil is bad?

 

[Mower Doctor 78006]

Apparently I misunderstood the question. I understood it to be that after warming up the engine would shut off. Run the mower for 20 min till hot. Pull the gastank, blower housing. Pull black coil wire. re install all parts you removed. Restart. If it restarts ok. with black wire pulled its the coil. If it doesn't restart with black wire pulled and engine hot. Possible cylinder expansion on heat cycling.

If it doesn't shut off until out of fuel, how is the coil bad?

 

[lzn197]

Apparently I misunderstood the question. I understood it to be that after warming up the engine would shut off. Run the mower for 20 min till hot. Pull the gastank, blower housing. Pull black coil wire. re install all parts you removed. Restart. If it restarts ok. with black wire pulled its the coil. If it doesn't restart with black wire pulled and engine hot. Possible cylinder expansion on heat cycling.

Am I missing something here? If you essentially disconnect the "electrical shut down circuit" from the mower, and it NOW starts, how can that be the coil? I would think that if it NOW starts, you have an intermittent short or grounded switch or wire condition in the shut down or engine kill electrical circuit.

I also am not understanding your comment about cylinder expansion. Can you explain that please? An exhaust valve will get much hotter that a cylinder ever will. That is why, in my comment, I said the valve clearance would be wrong and that causes many mower engines to not start when hot because the valve is held open slightly.

 

[Fish]

No, if you pull the kill wire and it starts, it means the coil is good, and the kill circuit is ground out the coil somewhere. But I doubt that any of that is his problem, let's wait and see what his engine's model numbers are.