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Hi,
I am bit desparate with my Honda HF1211 lawn mower (motor GXV340).
The motor starts without any problem when it's cold, but starting it hot mostly doesn't work.
As soon as the motor has cooled down, starting is OK again.
I didn't notice any sparks when starting hot, so I changed the spark plug as well as the ingnition coil.
But that didn't solve the problem; still no sparks when starting with a hot motor.
This problem is really driving me crazy.

By the way, when starting hot, the motor makes a weird noise during the first few seconds (as you can see or hear in this small video - between 10th and 14th second):
Honda motor starting problem - YouTube
Could a malfunctioning small starter solenoid produce such a loud noise? Or would it be the starter engine causing the problem?
Thanks for any advice.
Lukas

I watched the video with one of our tech guys from the engine group. He thinks the starter motor/clutch is dragging when the engine is hot. A good shop or someone experienced with starter motors may be able to better pinpoint the exact part and/or do some bench testing with it out of the tractor. It also may be a weak battery? Just a guess on that.

A entire new starter can be costly. There are many, MANY versions of the GXV340 engine (almost all made in Japan) and prices for a whole new starter run from $101 ~ $500 The good news? Nearly all the individual parts for most starters are still available from Honda.

Get me the serial number off the engine and I'll get you a full parts listing & prices.

Thanks for the interesting information, Robert!
A malfunctioning starter motor, would that in itself explain the lack of spark at higher temperatures?
Or would that rather mean that the starter solenoid is the main problem?
Thanks.

Lukaskas said:

Thanks for the interesting information, Robert!
A malfunctioning starter motor, would that in itself explain the lack of spark at higher temperatures?
Or would that rather mean that the starter solenoid is the main problem?
Thanks.

Click to expand...

So just to confirm, you have spark when the engine is cold, but no spark when engine is hot? How are you determining there is/isn't spark?

If you are absolutely positive there's no spark when the engine is hot, it may be an ignition issue. I'd try the easy stuff first, new spark plug, check the condition of the spark plug cap/wire, etc.

Thanks, Robert.

Yes, that is correct. The engine starts normally when it's cold.
But when the engine is hot, I can't restart. When I then check the spark plug, no spark.
I tried a new spark plug but that didn't solve the problem.
Same after changing the iginition coil: no spark when the engine is hot.

Lukaskas said:

Thanks, Robert.

Yes, that is correct. The engine starts normally when it's cold.
But when the engine is hot, I can't restart. When I then check the spark plug, no spark.
I tried a new spark plug but that didn't solve the problem.
Same after changing the iginition coil: no spark when the engine is hot.

Click to expand...

How was the spark plug wire/cap look? I doubt that's the problem, but maybe.

Otherwise, I'm trying to think what could disable the spark. Most riding equipment has a series of interlock switches (seat, shift lever position, PTO, etc.) that can turn off the ignition as part of the safety design. For example, if the unit is in gear or blades engaged, and you lift off the seat, the interlock will usually shut down the ignition.

That said, I've never heard of an interlock/safety design that would be temperature sensitive.

You may wish to see what you can find out from the actual rider's manufacturer. I can only comment on the Honda (engine) part of it. What brand of rider is this unit? If it was built new with a Honda engine, I might have some documents from our engine guys, but that's a longshot for troubleshooting.

The honda hf1211 is made by an italian company called GGP (global garden products) and badged honda.
Lots of OEMs in europe use them including John Deere.
Buy a product and paint it the colour you want and price accordingly.

As for hot no spark, disconnect the earth wire on the coil and see if it sparks.
If it does spark then problem in the safety switch side.
If it doesnt then problem in flywheel and coil.
For safety make an earth wire up to coil with a rocker switch so you can switch it off if it does starts.

Hi Pugaltitude,
I disconnected the earth wire on the coil and it doesn't spark either.
This only happens when the engine is hot. No problems at all when the engine is cold.
I have changed the ignition coil in the meantime as well, and ... same problem, no hot start.
The flywheel seems ok to me.

Your problem has to be in coil or flywheel then.

Is the gap between the coil and flywheel set right?

Is the coil spark plug cap ok? Is it a resister type cap or normal terminal type?

The flywheel magnets may have lost there residual magnatism.

Yes, gap between coil and flywheel is set as recommended (0.4 mm).
The spark plug cap is renewed together with the coil.
About the flywheel magnets losing their residual magnetism, wouldn't you expect this to cause problems with cold start as well?
I'm only having trouble with hot start.

This problem is driving me crazy ...

@ Robert: The weird sound has gone. It was indeed a low battery that caused the solenoid making the ticking noise. I guess the battery must have gone low because of the many restarts.
But still, the engine won't start when hot. No sparks.

Lukaskas said:

@ Robert: The weird sound has gone. It was indeed a low battery that caused the solenoid making the ticking noise. I guess the battery must have gone low because of the many restarts.
But still, the engine won't start when hot. No sparks.

Click to expand...

Disconnecting the earth wire from the coil takes away all the other electrical components on the rider. So if its not sparking with that disconnected its got to be either coil, flywheel magnets, cap or plug.
Nothing else electrical is connected to it.
So going with what you are saying there is only one thing left to change.

Just to make sure that i'm doing it correctly: when checking for spark in this case (with disconnected earth wire from the coil), I sill hold the spark plug to the metal surface of the engine? Correct?

Lukaskas said:

Just to make sure that i'm doing it correctly: when checking for spark in this case (with disconnected earth wire from the coil), I sill hold the spark plug to the metal surface of the engine? Correct?

Click to expand...

Now i should have asked you this 1st!
Are you using a spark tester?
A spark tester loads the coil to its full capacity and also can load the spark plug when under compression conditions when still fitted.
This might show you something different hopefully!!! :thumbsup:

Hi Robert,
No, I didn't use a spark tester. Just did it the usual way by making contact with a metal surface.
It works when the engine is cold so I guessed it should work with a hot engine as well (even when the coil in no longer earthed).

Lukaskas said:

Hi Robert,
No, I didn't use a spark tester. Just did it the usual way by making contact with a metal surface.
It works when the engine is cold so I guessed it should work with a hot engine as well (even when the coil in no longer earthed).

Click to expand...

If you are getting a positive spark test when cold, but the same test fails when hot, then something is getting too hot and is killing the ignition. Could be the coil, plug, cap, wire, or any other part of the interlock system (relay, wires, connectors) that can disable the ignition when a certain safety/logic circuit is not "ready" to let the ignition operate. I don't have access to service data for the European model, but the above should apply to any riding equipment. Hope this helps.

Robert,
As explained above, even without any further connection to the electrical circuit by disconnect the wire from the coil, there is no spark. This should rule out any problem with the 'interlock' system.
This 'test situation' only involves the flywheel, the (disconnedted) coil and the spark plug.

Heat raises resistance in wires and connections-especially corroded connections. Check and clean spotless any and all. Since no spark, start by checking for voltage at coil, a safety pin probe into the wire should suffice, tape hole when done. None there, keep going backwards-you'll find it. Heat is the key here.

Hi All,
The problem is solved! The issue was the flywheel being a bit rusty. A little sandpaper made the trick.
As simple as that. I am so happy.
Many thanks to all.

Lukaskas said:

Hi All,
The problem is solved! The issue was the flywheel being a bit rusty. A little sandpaper made the trick.
As simple as that. I am so happy.
Many thanks to all.

Click to expand...

Hi Lukaskas
I've recently purchased a second hand Honda 1211( my first tractor mower)
I have exactly this problem and have been through an similar diagnosis as yourself.
Could you post a discription or pic of your fix?
Im afraid in not the most mechanically minded even athe steps to get at the flywheel to inspec would be cool.?
Thanks in advance
Sitter