twybrow
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| posted on 11/7/12 at 07:51 AM |
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Briggs and Stratton vertical shaft engine help
I am currently in France at my parents house, and my dad has managed to blow up his ride on lawn mower! Apparently, it was running quite hot, and
kicking out blue/white smoke. When he turned it off, it kept running by itself! Eventually, he managed to stop it, but when he went to restart it, it
made a loud bang, and wont start. The engine turns over very easily (it can be turned over by hand) on the crank.
The engine is a 15-20 year old, and is an 11hp vertical shaft engine. I have removed it from the mower, in preparation to either strip it down, or
replace it... We took it to a local B/S dealer, who without even looking at it, said it was dead, and not worth looking at (bloody lazy French!)...
Now the question for the LCB massive, is it even worth tearing into it (I suspect I will be volunteered to take it home in the UK with me to look
at)? I can source brand new repalcement engine for ~£550+ shipping from the UK, or possibly a short engine if I can track one down... Or I can get a
rebuild kit, which included a new standard piston, piston rings, gaskets etc for $150 from the US...
So people.... what should I do!? Is is beyond economical repair?
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owelly
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| posted on 11/7/12 at 08:08 AM |
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It's fecked. The reason why it was running when you switched it off is because it was dieselling. Which is running on the lube oil like a diesel
engine not running with a spark. I'd say the lazy French guy was right. There are plenty of second hand engines on Ebay so its not worth trying
to repair yours.
http://www.ppcmag.co.uk
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designer
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| posted on 11/7/12 at 08:41 AM |
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Yep, you need a new one, and the lazy french bloke told you straight away instead charging you to 'diagnose' the problem.
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twybrow
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| posted on 11/7/12 at 09:37 AM |
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Fair enough....! The French bloke might have been prompted by my mum walking into the shop and saying 'We want to buy a new John Deere
tractor.... Oh, and we have the engine from our current tractor for you to look at in case you can fix it' - so I am guessing, his motivation
might have been partly prompted by that!
But thanks chaps... I am left a little stuck, as we are now being told the old engine isn't available as a direct replacement, and the new
version would not be a direct replacement (the zorst comes out on the other side of the engine).... The supplier in the uk is suggesting to strip it
down, and just replace anything that looks worn out, but I am worried that if it has overheated, then there may well be issues with warpage etc that
wont be fixed by replacing parts such as the piston, rings etc. Will the dieseling have done any particular damage, or is it more a sign that it was
fooked anyway?
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MakeEverything
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| posted on 11/7/12 at 10:03 AM |
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tbh, i would bin it. If you were looking to buy a new one then i would, to save the aggro of looking for parts etc.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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MikeCapon
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| posted on 11/7/12 at 10:15 AM |
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Strangely enough I have a vertical crank B+S ride on over here too! Except mine's not blown up. Yet.
What have you got to lose. Get it apart and take a look. If it still turns over by hand there's got be hope of fixing it. These motors are so
crude it's frightening but the upside is that they will tolerate all sorts of things before giving in and refusing to run.. And they are a piece
of cake to strip and reassemble.
Worst comes to the worst you'll probably find another ride on cheap on Ebay. Mine's a 120" cut, 18 HP 600 twin and cost me 500 euro
or £400 in real money..
www.shock-factory.co.uk
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owelly
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| posted on 11/7/12 at 10:18 AM |
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I would say the dieselling will have used up all the oil in the crank case so the bearing will have run dry and the piston rings will have lunched
themselves and the cylinder. It's only a few bolts to whip the head off so it may be worth having a look but as I've said, Ebay is full of
these engines so just buy another and bolt it on. I have a spare one here but by the time you take into consideration the cost of the engine plus
postage, you'd be better off buying one closer! Or, buy a new John Deere...
http://www.ppcmag.co.uk
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JeffHs
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| posted on 11/7/12 at 10:32 AM |
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Take it to bits. In my opinion the dieseling does not necessarily mean it was running on engine oil. A coked up carb engine with a hot spot will keep
running on petrol until you stall it.
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Confused but excited.
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| posted on 11/7/12 at 11:59 AM |
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quote:
Originally posted by MikeCapon
Strangely enough I have a vertical crank B+S ride on over here too! Except mine's not blown up. Yet.
What have you got to lose. Get it apart and take a look. If it still turns over by hand there's got be hope of fixing it. These motors are so
crude it's frightening but the upside is that they will tolerate all sorts of things before giving in and refusing to run.. And they are a piece
of cake to strip and reassemble.
Worst comes to the worst you'll probably find another ride on cheap on Ebay. Mine's a 120" cut, 18 HP 600 twin and cost me 500 euro
or £400 in real money..
 120" cut. Jeez Mike that's a combine harvester not a lawn mower!
Mind you for £400, I can see why you bought it.
[Edited on 11/7/12 by Confused but excited.]
Tell them about the bent treacle edges!
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MikeCapon
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| posted on 11/7/12 at 12:32 PM |
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120" cut. Jeez Mike that's a combine harvester not a lawn mower!
Mind you for £400, I can see why you bought it.
[Edited on 11/7/12 by Confused but excited.]
It is a bit tricky in confined spaces but the 'garden' here is about 1.25 acres. It takes six hours to cut with a push mower...
The only downside is the bloody noise that the three rotary blades make. When they are turning you can't hear the motor. Ear defender job.
www.shock-factory.co.uk
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Paul_C
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| posted on 11/7/12 at 01:41 PM |
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I agree with JeffHs. The mower was probably running on helped by the engine running hot. Turning off just removes the spark ignition. If it has a hot
spot in the head it can run without the spark plug. Some old UK cars were susceptible to this and I believe that a solenoid valve to cut off the fuel
supply was used on one model.
The bang on restart may be just a back fire in the exhaust.
It's worth investigation just though I had a mower which was stolen with a Briggs and Stratton engine. That was the best thing that ever
happened to it. The carburetion used a 'PulsaJet' or something similar. You could tune it to start and run cold or tune it to run hot but
not both. Also when delivered the ignition timing was out and once it managed to grab the start pull handle out of my hand. Not a pleasant experience.
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Canada EH!
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| posted on 11/7/12 at 02:42 PM |
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I agree it's toast, had the same thing happen many years ago. Replacement engine at that time was $200.00 Canadian complete with electric start.
Have a look around replacement engines are not that expensive, that replacement $200.00 engine is still going after 20 years (went to a Kohler).
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MikeRJ
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| posted on 11/7/12 at 03:44 PM |
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Sounds like it's low on compression which possibly means the rings and maybe bore is worn, and this would lead to carbon deposits in the
combustion chamber and piston crown which would cause the running on. It could be as simple as a burnt valve seat or head gasket problem causing the
low compression however.
There's no way I would be so quick to condemn it to the scrap pile without stripping it down first (which is pretty easy on these engines).
[Edited on 11/7/12 by MikeRJ]
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twybrow
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| posted on 11/7/12 at 05:47 PM |
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Thanks chaps - some great advice there. There are plenty of lawn mower engines on ebay, but finding one, that we can get shipped to France, and that
is a direct fit is proving tricky. B&S dont make the exact model anymore - the replacement seems to be a slightly larger and newer version. I can
find various vertical shaft engines, but are they a standard fit/bolt pattern?
There was definitaley oil left in the engine, as it pissed everywhere when we tipped it over to take a closer look. Also, it appear the seal on the
oil filler tube has gone - I dont know if this is related (ie too much crank pressure blowing the oil pipe out?).
I might whip the head off tomorrow, and see what I can see - as you all say, nothing to lose (if I was at home, and it were mine I WOULD get it
stripped down and running again I'm sure but alas, my old mn does not have the tool set or bravery I have!
Owelly - if you have a spare, then believe me, my dad is very much up for buying it if it is compatible! What exactly have you got?
As a final kick in the balls today, his fairly new self-propelled mower is now also broken! The dead mans handle has lost its return (although the
spring seems to be in place as it should), and far more serious - when you rotate the engine by hand, you can hear at one point on the rotation, a
metal on metal sound (twice in quick succession) which seems to be coming from the flywheel area.... Needless to say, he is not overly pleased with
his mower collection today! 
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The Shootist
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 posted on 11/7/12 at 07:28 PM |
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Tune- up
Tune it up. Maybe rebuild or replace the carb.
A side valve Briggs doesn't have enough compression to "run-on" on it's own oil...they barely can burn gasoline.
A worst pull the head and clean the carbon out. If it doesn't burn a lot of oil it should be OK.
Shut down is achieved by shorting the ignition so i would check the engine electrical.
Lots of Briggs info online.
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matt_gsxr
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| posted on 11/7/12 at 08:32 PM |
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Has he considered a small goat herd?
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paulf
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| posted on 11/7/12 at 10:09 PM |
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I used to work for a company that often had small industrial engines to repair, the B&S engines were the worst and not worth the bother when worn
out, they used to have counter balance weights on the crank with shells that wore out and alloy bores that could not be re bored hence the
availability of standard size pistons only.
Paul
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The Shootist
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| posted on 12/7/12 at 04:05 AM |
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Depend on the engine.....
"I used to work for a company that often had small industrial engines to repair, the B&S engines were the worst and not worth the bother
when worn out, they used to have counter balance weights on the crank with shells that wore out and alloy bores that could not be re bored hence the
availability of standard size pistons only.
Paul"
Depends on the engine. The actual "Industrial" series engines are cast iron sleeved and fully capable of overhaul. The home user engines
are silicon aluminum blocks that are pretty much disposable.
The aluminum engines do fine as long as oil level is maintained, but are throw away if excessively worn. The Industrial series engines are tough as
nails, and most riders on this side of the big ocean come with the cast iron engines.
If his engine is aluminum, but is not hogging oil, it should be fine to use.
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twybrow
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| posted on 12/7/12 at 11:42 AM |
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Well we stripped the engine today, and I was surpised that when we lifted the head off, it looked quite goo. Then we rotated the crank, and nothing
moved! I pushed on the piston crown, and it moved freely.... Hmm. So it looked very much like a broken rod, which was well and truly confirmed when we
stripped it a bit further (for fun you understand).... As we took off the carb linkage, I spotted a hole in the casing. When we split the bottom end
cover off, the full story was revealed....
This was the remains of the con rod, that was scattered liberally around the block! The con rod has well and truly disintegrated, and smashed what I
assume is an oil pump, and the block - so in summary, it is FUBAR! So now on the lookout for a cheap second hand lump to drop in. Still, a fun morning
was had by all! 
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