Small Sit On Lawn Mowers

[Lower]

It seems potty that an electric start machine doesn't have a charging system (I have see this on one or two walk - behinds though) but Mr. H seems adamant so I'll bale out of this one!
For sure, a 9 a/h battery ain't going to last long at all.
John

Thread resurrection for accuracy. I was wrong when i thought that my mountfield 827H ride on mower doesn't have a charging system. It does.

I've been trying to diagnose why my mower struggles to start when its hot. I think its the starter motor causing the problem when it gets hot and is taking an excessive amount of battery power to turn the engine over, ultimately flattening the battery. I checked the battery voltage when the engines running after a start and it drops to about 12v during the start process and then gradually recovers to around 13.6 volts which is higher than the battery delivered when it was fully charged but without the engine running. Ultimately, to prove it i started the engine and disconnected the battery whilst it was running. It continued to run, so must be generating its own power.

I've got a new starter motor to fit to see if that cures my problem.

 

[Burnerman]

Even when these engines are fully hot, they may need just a half second of choke to get them going again.
Other than that, try full throttle but backed off a fraction.
John

 

[Lower]

Even when these engines are fully hot, they may need just a half second of choke to get them going again.
Other than that, try full throttle but backed off a fraction.
John

It actually struggles to turn over when its hot, been running for a while and had 2-3 starts. It'll turn over, but too slowly to start the engine and then it won't even turn over. Typically, when it happens leaving it for a minute or so results in it turning over faster and then starting. This is with a brand new, fully charged battery. That's why i think its the starter motor.

 

[Burnerman]

Do post back with the result!
John

 

[Old Salt]

Are all the battery and starter connections clean?

 

[Hysteresis]

Thread resurrection for accuracy. I was wrong when i thought that my mountfield 827H ride on mower doesn't have a charging system. It does.

My Mountfield 827H definitely did NOT have an Engine Driven Alternator charging system. The charging of the battery had to be undertaken using a Mountfield supplied Mains battery charger.
My 827H was returned to the supplier as two attempts to 'FIX' the Starting Problem by the dealer failed and I lost Patience and confidence with it.
Recent postings suggested the Starting Failure was low battery charge or clean connections, those suggestions were not relevant, my problem was with a FULLY charged battery, the starter motor would simply NOT rotate, all connections were clean, in fact the machine was brand new from the factory. I think the problem was the starter motor drive cog was sticking engaged with the starter ring and as such the motor could not develop any rotational inertia to commence turning the engine. I never found out how the dealer addressed the problem, I assume they sold it on to some unsuspecting buyer at a reduced price.

 

[Burnerman]

I think it’s pretty unlikely that the starter pinion gets locked into the ring gear......the over speeding causes a loud squeal before the pinion disintegrates.
Some Briggs engines have a decompressor device fixed to the camshaft that allows the engine to spin up a little more willingly but I don’t know if this applies to your particular engine.
John

 

[Lower]

Do post back with the result!
John

Changed the starter motor this afternoon. The workshop manual is certainly more of a trail of clues than an actual manual!

The mower now starts every time. When I mowed the lawn after changing the starter motor, I must have stopped and started it 20-25 times and it started without any difficulty every time. It used to start to struggle when it was hot after 4-5 starts and you could smell burning. At the end of the mowing session the battery voltage was 13.2v whereas with the old starter motor is would finish up at about 12.5v, so the starting current draw must have dropped significantly and no longer kills the battery.

Interestingly, the cable on the new starter motor now has a dedicated earth connection which I bolted to the engine block whereas the old one didn’t.

Good news for me anyway. Hope it lasts!

I’m still topping up the battery with the supplied charger, but it barely needs it.

 

[Burnerman]

Congratulations on an excellent result!
I can’t say I’ve come across a starter with a dedicated earth cable connection so that’s a new one for me.
Thanks for posting back, it’s appreciated!
John

 

[morqthana]

But Quotes are between £100 and £150

Unless there's something really awkward about it, it's what, an hour or so?

I would have thought you could find a local schoolkid to work for quite a lot less.

A robotic thingy would not really be suitable as the lawn is too big

They're also not much fun if any of the local wildlife or domesticated animals has left you any presents.