Toro Clone Engine Is Killing Me Help!

[Normstorm]

There are 2 two ways to fix an engine
1) toss new parts in till you fall over what is wrong
2) diagnose what is wrong then fix it.

Now the engine runs fine without the blower housing off but won't start with the blower housing on, so there is your first clue.
There is some thing that connects to or rubs against the blower housing that is preventing it from starting.
I have found a problem with the microswitch not travelling quite far enough to break the kill circuit.
The switch on these is normally closed so when the plunger moves far enough the kill circuit is opened and the magneto creates a spark.
So tie the bail to the handle and check to see if you have a spark
This engine should have an auto choke so the choke butterfly should be connected to the muffler with a control rod.
This rod can get fouled on the blower housing so either won't close fully or won't open fully/
People have a bad habit of ripping them off if the engine will not start.

As you have no idea what you are looking at please remove the blower housing and take some nice clear in focus photos.

The repair manual for the Loncin engine is on Toro's web page.

BERT - You got my number. I for sure went #1 route on this thing. I NEVER should have mentioned the blower housing "rubbing" on anything. I can't explain that but it fixed itself by me just taking housings off and putting back on more carefully. Mower runs fine with housings OFF and ON.

The Toro drawing confused me but I figured out where the thermal switch was located on the muffler. Since Electric start will work I just started it with housings OFF so I could watch the thermal switch heat up. It fully opened the choke as muffler heated up probably in less than a minute so I do NOT think the thermal switch is any problem. Put housings back on and gaped the Spark Plug at 0.30. Cold engine fired right up NP.

I will study the engine manual and see if troubleshooting section helps. Thanks for your reply! Will try using mower some more tomorrow and update.

 

[jp1961]

Hello,

The alternator just charges the battery when the motor is running. The wall charger is just a backup to use if the mower hasn't been run for a while.

I'd say check compression (hard to do because most engines use a decompression feature, but check YouTube fore any helpful videos) and valve lash.

You've already addressed any issues with the carb or coil.

Regards

Jeff

 

[Rivets]

For those who may not know this, but there is no alternator on push mower engines. The batteries need an external charger. More than likely your problem is that the valves are out of adjustment, when the engine gets warm.. Intake should be .004-.006” and Exhaust should be .006-.008”. As Bert sai, down load the service manual, which has an excellent description on how to do this.

 

[Normstorm]

Hello,

The model and serial number you provided (20374 / 400745059) show it to be an electric start, so it should have the alternator.

The "thermal switch" appears to be a mechanical one, not electrical, so are there any bell cranks on your carb that don't have a rod going to it?

It is possible somebody put a different engine on your mower (sort of a Frankenmower), not unusual or uncommon on C.L.

Regards

Jeff- Very Confusing RE Electric Start & Charging. Honda's HRX217HZA for sure charges the battery while the engine is running so it probably has an alternator?

Toro Paper Manual that I got with mower clearly shows that the charging system is a plug into wall 12 volt charger and it plugs into mower half way up handle to a tiny plastic connector. Manual says NOTHING about any engine charging. Toro must make at least one mower that recharges the battery from engine alternator?

Toro's online parts show an alternator for this model but I think thats a mistake or something. The Clone engine manual also shows the alternator so who knows? I have to assume my engine has mounts for one because maybe different model(s) use the same engine with an alternator add on?
Anyhow I guess Valves are next then "blown" head gasket. I don't understand how the engine could seem smooth running and powerfull if either of those were an issue but the backfiring says different I guess.

Appreciate your insight thanks.

 

[Rivets]

I’ve been working on Toro mowers for 40 years and the Loncin engines since Toro started using then roughly 10 years ago and have never had one with the alternator show on the parts diagram. Don’t even remember these being talked about in any update schools or materials. Secondly, the charging system, if there is one, has nothing to do with how the engine starts or runs. They are not connected in any way and you don’t need a charging system to make these small engines run. The three things you need are spark, fuel and compression. If you know you have spark and fuel in the cylinder, you then must test the compression system. Easiest thing to check is valve clearance.

 

[bertsmobile1]

As previously mentione the only big problem I have had with the Loncin engines on push mowers is the housing for the bake & cut out switch warping so the switch did not allow a spark to happen.
I have put some back together and managed to get the choke control rod messed up so it was fouling & not working properly

If this engine has the air vane to turn the choke off when the engine is running then the air vane & thermal controls rods an get crossed up.
This is why I asked for the photos.

As for push mowers charging batteries, Honda do an alternator in the 190 series engines.
Victa down here had a charge coil inside the magneto coil that sent a pulse to the battery through a diode.
Talon & Sanli both do a push mower with a charging circuit.
And none of them work particularly well and all need the occasional top up from a plug in charger.

 

[Normstorm]

As previously mentione the only big problem I have had with the Loncin engines on push mowers is the housing for the bake & cut out switch warping so the switch did not allow a spark to happen.
I have put some back together and managed to get the choke control rod messed up so it was fouling & not working properly

If this engine has the air vane to turn the choke off when the engine is running then the air vane & thermal controls rods an get crossed up.
This is why I asked for the photos.

As for push mowers charging batteries, Honda do an alternator in the 190 series engines.
Victa down here had a charge coil inside the magneto coil that sent a pulse to the batter through a diode.
Talon & Sanli both do a push mower with a charging circuit.
And none of them work particularly well and all need the occasional top up from a plug in charger.

***THANKS BERT***. I ordered cut out switch, Carb Insulator & Air cleaner "prefilter" since wasn't one on it. I bent the muffler cover slightly to make a little more room for Thermal Switch Arm to operate freely. Will check air vain linkages for binding against each other. Guess I will try and learn valve lash adjustment thing. Maybe its not as difficult as I think - never done B4.

 

[Normstorm]

That's a lot of experience. I guess will have to try and do valve adjustment. I sort of thought if it was valves or compression that the engine wouldn't run smoothly or have good power at "working RPM". When this engine fires up it just sounds incredibly good. Thanks for help.

 

[bertsmobile1]

Do the vale lash exactly how the manual says
The longest & hardest part is cleaning the old gasket / sealant off the rocker cover
And remember you are not mooring the USS Missouri.
Go for the middle of the specs.
Get any 10 mechanics to set valve lash and you will get 12 slightly different settings, it is subjective feel .
When I started on engines decades ago I was given a massive set of feeler gauges.
The mechanic who showed how to set a gap put the feelers in and then tightened the joint
His instructions were you should be able to pull the feeler out but if you let go it should stay there.
1,2 or 3 thou either way makes little difference to a mower engine.
A full blown race engine yes but a mower engine no.

 

[Normstorm]

Do the vale lash exactly how the manual says
The longest & hardest part is cleaning the old gasket / sealant off the rocker cover
And remember you are not mooring the USS Missouri.
Go for the middle of the specs.
Get any 10 mechanics to set valve lash and you will get 12 slightly different settings, it is subjective feel .
When I started on engines decades ago I was given a massive set of feeler gauges.
The mechanic who showed how to set a gap put the feelers in and then tightened the joint
His instructions were you should be able to pull the feeler out but if you let go it should stay there.
1,2 or 3 thou either way makes little difference to a mower engine.
A full blown race engine yes but a mower engine no.

***BERT great "sayings"!

***And remember you are not mooring the USS Missouri*** Had to look that up. I knew the Japanese surrendered on it but I thought it was a carrier and I thought it was still moored an hour away in Bremerton WA. Forgot that they towed it off to Hawaii for final resting spot.