Starting & Cutting Out Issues.

[StarTech]

Just because a spark plug fires outside the compression zone does not always mean the spark plug is good. You to try a known good spark plug. And yes I have seen plugs to fail after heating up too.

 

[ran440]

To confirm a fuel problem next time it quits, remove the air filter and shoot some starting fluid down the carb. If it starts right up, it's a fuel problem. Next loosen the fuel cap and try to start again after a few minutes. Sometimes the vent in the fuel cap becomes restricted and won't let air in. No air in, no fuel out.

 

[kjonxx]

I could be mowing the lawn for varying short lengths of time and then the engine just starts to miss fire and cut out, when I try to start it again it won’t start, I can leave it for a while, go back to it & it could start again straight away.
There was a little debris on top of the outlet filter in the plastic fuel tank which I syphoned out & there wasn’t any debris in the carb float bowl.
The change of plugs didn’t make any difference, also the plug wasn’t soaked with petrol either but it was sparking.
Regards.

Coil

 

[Wheels]

Simply test for you. I have seen this a lot and would try the gas cap test. The fuller the gas tank the quicker the engine could die out. Emptier gas tanks could run a long time before it fails. So with that fill the tank at least 3/4 full. Run it and see when it dies. Then loosen but not remove the gas cap and see what happens. Simple test, if nothing changes then I agree with coil problem.

 

[Alan46]

I would go with the gas cap not venting properly, I’ve had that happen on to different machines!

 

[RevB]

Hi,
I have a 4 years old Toro 21766 recycler mower (photo attached) which has develop erratic starting & cutting out issues.
I have flushed out the carburettor & the petrol tank, replaced the spark plug & the lead but these problems still exist.
Please can anyone suggest any reasons why I’m experiencing these problems.
Regards.
View attachment 68293

"Featuring the lightweight 7.25 lbs gross torque, 163cc overhead valve engine featuring No Oil Changes ever." Cut and paste from advertising.

Please tell us if you followed this last shit piece of advice.

 

[scoyote]

The underjetted cartridges in these ohv Briggs engines are usually the culprits --but if you can run that long and rule out a coil failing ---i would look at fuel delivery. I'd lean more towards a venting issue. These mowers are not cap vented ----they are tank vented into the filter backing plate. I've seen the odd case where the fuel seems to siphon out the vent and leak behind the filter--very rare--but i might want to try plugging that vent and drilling a hole in the cap from the inside

 

[Camms61]

"Featuring the lightweight 7.25 lbs gross torque, 163cc overhead valve engine featuring No Oil Changes ever." Cut and paste from advertising.

Please tell us if you followed this last shit piece of advice.

Definitely not, I change the oil at the start of the mowing season.
Regards.

 

[kbowley]

Fuel cap vent. Soak the fuel cap in some dish water and rinse well. next time it happens try loosening the cap and see if it fires up. alternately simply purchase the correct fuel cap from Toro dealer and be done with it. But first check to see if it fires up when you loosen the cap.

 

[Oddjob]

Here’s an easy issue to rule out or in: do you have an autochoke on this machine? If so, next time the engine dies on you take off the air filter and visually confirm if the choke is open or closed. If it is stuck closed then you have your answer. Taryl Fixes All has a good video on fixing or replacing autochokes. Personally, I just gently manually move the lever back and forth until the autochoke mechanism freely moves.