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Lawnmower refuses to start when hot

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  • Jun 7th, 2020 7:23 pm
[OP]
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Dec 9, 2005
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Ontario

Lawnmower refuses to start when hot

I've a Toro 7.5HP self-propelled ("Personal Pace") mower that refuses to start when hot.

I've checked and cleaned the carb, replaced the spark plug and ignition coil, tried with the gas cap off, fresh gas, and fresh oil. Compression seems fine. The engine itself is relatively clean and free from debris.

I'm at a loss and wondering if anyone had any suggestions, something I'm overlooking.

Thanks.

It's relatively newish (5-7 years). I just need to get it working enough to do the lawn and then I'll replace it with a rechargeable. Also the two riding lawn mowers that are really old and a lost cause. But that's not important.
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5 replies
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Dec 9, 2003
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Calgary
Could be a vapor lock on the fuel

Or the choke sticking

Or the air filter restricted
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[OP]
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Dec 9, 2005
3483 posts
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Ontario
Cough wrote: Could be a vapor lock on the fuel

Or the choke sticking

Or the air filter restricted
Thanks. It responds the same way if the gas cap is off or the air filter removed.

The choke was sticking a bit, but it moves freely now yet did not solve the issue.

It doesn't have prime or a manual choke It claims "No prime. No choke. Starts every time, guaranteed"
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Jul 31, 2007
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OP, I have the same problem with my one-month-old Toro 20353 mower too. After 6 pulls it finally started. When it is cold start no problem just 1 or 2 pull at the most.
[OP]
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Dec 9, 2005
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Ontario
Addendum here.

Using some quick start will get it running. It runs fine until I shut it down (empty bagger, too much wet grass, etc.).

I'm beginning to think maybe I should just shoot it.
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Jul 4, 2004
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I've had this exact same problem with a Craftsman that has a 7.5hp Koehler motor. Personally, I just think these engines run far too hot compared to a regular 4.5hp to 6hp lawnmowers and can't take the heat that's generated. In-fact, when I opened up the gas cap to check for fuel, the fuel was bubbling like it was boiling! Never saw that before.

Now when I use the Honda mower from the 80's that has a much smaller motor, no problems restarting at any temperature. What I did do was adjust the throttle down a bit and will have to test it when the grass needs to be cut next.
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