Lawn Mower problem

[kc]

I am sure someone on the forum will have encountered this problem and know what the likely fault isI

 

Having a problem starting my ride on mower this week- its been used every few weeks this summer and always started OK - however on Tuesday it was very cold and it only just turned over on the starter.    After a few tries the starter could be heard rotating the engine but rather too slowly to start.  Slight smell of petrol so fuel present.   Low battery I thought and charged the battery overnight.   When unplugging the battery the connecting plug was distinctly very warm but not too hot to touch. Tried again next day with the fully charged battery and solenoid just clicked- starter didnt turn at all unlike previous day!     Duff battery I suspected, it's 6 years old, so fully charged my reserve battery - a 1 year old Yuasa 12v 7 aH gel cell,  good battery it started my car when I needed it to!   Again same result just the solenoid clicked. No sound of starter at all. Tried all the obvious things - applied brake,  not in gear, rocked machine too and fro, waited & tried starter again after a few minutes.    Could it be just two  poor batteries or could the starter have jammed?   I don't know much about the hydrostatic transmission on these mowers is it a fluid flywheel?    Could this be dragging the starter revs down?  Or a solenoid problem? 

Of course I could just buy a new battery and try again. It's the end of the season and the mower won't be needed until next Spring so it's not urgent. 

 

Details are

Atco Rider 27H ride on with hydrostatic transmission, Used regularly for 6 years but never had it serviced so far.    Briggs and Stratton 190cc  engine   fresh E5 petrol.

  12volt 8ah  original Chinese gel cell  I found connector -usual 6mm push on- was actually also soldered on!   had to unsolder to try the other battery but left replacement unsoldered but pushed on firmly with plenty of contact area. 

What do I try next!  Any ideas?

[Ron Gray]

Sounds like a stuck starter motor. You will probably have to remove it as rocking a hydrostatic transmission won’t help. If you can see the connectors on the starter you could try and short the connectors with a big screwdriver (lots of sparks)!

[Kim Taylor]

Usually turning the engine the 'wrong' way using a spanner on the end of the crank (assuming you can see it) will release a jammed starter motor. 

Could also be a faulty solenoid - is the starter a per engaged type (integral solenoid) or bendix type (separate solenoid wired to the starter windings).

If the latter, short across the power in & out terminals with a screwdriver or similar to isolate the fault (see Ron's post above)- if the starter turns, it's the solenoid at fault, if it doesn't, it's the starter motor.

hth

Kim

[Zflyer]

take the plug out, leave battery disconnected engage gear and rotate blade or roller. This will usually disengage a starter. 

[Ron Gray]

31 minutes ago, Zflyer said:

take the plug out, leave battery disconnected engage gear and rotate blade or roller. This will usually disengage a starter. 

Not if it's a hydrostatic drive.

[Rich Griff]

Are you saying the engine has not even had a single oil change in 6 years ?

 

See parts exploded views and wiring diagram...any oil in the engine ?

[Piers Bowlan]

On my Westwood you can turn the engine just by pushing the grill on top of the engine if you remove the plugs. Personally I doubt the starter is jammed if it was previously turning over, albeit slowly.

 

Have you tried removing and cleaning all electrical contacts particularly removing the solenoid, as on mine if there is corrosion/oil between the solenoid and frame there will be a poor earth connection and very high resistance, hence the hot wiring. If it is very cold too the amps will go through the roof and the battery(s) will simply give up.

[Learner]

3 hours ago, Piers Bowlan said:

On my Westwood you can turn the engine just by pushing the grill on top of the engine if you remove the plugs. Personally I doubt the starter is jammed if it was previously turning over, albeit slowly.

 

Have you tried removing and cleaning all electrical contacts particularly removing the solenoid, as on mine if there is corrosion/oil between the solenoid and frame there will be a poor earth connection and very high resistance, hence the hot wiring. If it is very cold too the amps will go through the roof and the battery(s) will simply give up.

Yes bad earth was my first thought.

Edited October 20, 2023 by Learner

[Robin Colbourne]

Could the motor brushes have worn down to the point that there is no longer enough pressure for them to transmit the current to turn the starter motor?  I've had this on a number of car starters and the equivalent problem on alternators.

As Piers suggested, check every connection along the route from the battery to the starter and the same on the negative return side.  Undo the connection, clean mating faces to bare metal, smear with Holts No-Crode or vaseline (the connections, not yourself... 😄 ) and retry.

One more possibility is that the starter ring gear and/or the gear on the starter, have worn to the point that they have jammed.  All the wear is in one place (coming up to compression) so worth taking the starter off to check this, if you don't find the fault elsewhere.  I had a Morris Ital on which the ring gear fell off the flywheel(!).  We did the usual shrinking it back in place, but even when cool it could be slid around the flywheel.  A few tacks by the welder at work cured that!

If the oil really hasn't been changed in the engine after six years, its about time it was!

If you do need brush gear, then 'Mid-Ulster Rotating Electrics' are my mail order 'go to' source for anything starter or alternator related, plus they do some Briggs & Stratton bits too:  M.U.R.E Briggs & Stratton parts

[Peter Christy]

Also worth checking for a corroded earth connection. Starters draw a lot of current, so the tiniest bit of resistance anywhere will cause the volts to drop alarmingly at the point where they are needed.

 

Check where the earth lead from the battery is connected to the chassis/engine/whatever. Clean with a wire brush, and apply some grease to prevent corrosion returning, before re-tightening.

 

A common fault on the old bangers we used to run as students many years ago....!

 

--

Pete

 

[kc]

First of all many thanks to the forum members for their advice, and also to one of my clubmates ( who is also a forum member ) who offered to come around to help.   It shows what a great hobby this is and also the depth of knowledge of aeromodellers.

 

I think that Piers comment is likely the most apt, so possibly the thing I will investigate first.   The starter never made any noise to indicate it had jammed, it's just when I changed the battery over that the solenoid clicked instead of turning the engine.   The 4 pin connector ( battery lead to machine ) which got hot is my No 1 suspect.   It's got extra wires which seem to just connect the pins in parallel.   Lots of connections which may have loosened when I removed the battery.   Anyway it will wait until the weather is better.......

 

Actually this mower has very low 'mileage'  ( yardage?) it's only used for about 15 minutes  8 times a year.   So total about 12 hours running in 6 years!  Maybe 4 miles a year so 24 miles in 6 years.  Hence I haven't bothered with oil change or servicing.     I wouldn't expect to change my car's oil after 12 hours -  it would mean a round trip to Scotland would involve a stop for oil change on the way home!    I find most things run better without ham fisted mechanics meddling.   If it aint broke don't fix it  is my motto.    I know some may disagree with this but it has worked on many things.  But I do keep a very sharp eye on things to ensure they run smoothly.

 

To explain the low mileage -  the ride on mower just mows the main lawn area and all the fiddly parts are mown with a Spear & Jackson 24 volt cordless.  Great bit of kit and recommended.   Very light and my wife ( The Head Gardener ) likes using it = more flying time for me!

 

So thanks for all the help,  when the weather is better I will look into this and report back.

 

 

[Martin Harris - Moderator]

Oil does degrade over time even when an engine is in storage, especially once put into use and subject to heat cycles and exposure to condensation and combustion byproducts - it will lose viscosity and sludge can start to form. 
 

While there can sometimes be a case for leaving well alone, oil needs regular changing regardless of usage.  Engines are designed to be serviced so there shouldn’t be any mechanical downside to routine servicing. 

[Engine Doctor]

Six year old oil will be knackered by now and probably turned to a very thick sludge. That in turn has probably killed the starter motor .Oil  absorbs contaminants from burnt fuel and moisture from the air. It should be changed annually regardless of use. If engine has survived change oil asap. 

Edited October 20, 2023 by Engine Doctor