Advice re mower project - crankshaft repair

[visor_down]

Hi all,
Have bought a mower as a bit of a project to do up, it's a Hayter only few months old and the sellers gardener ran it with low oil, it threw the con rod out the crankcase.
I was hoping to avoid buying a new crank as they are not cheap from Briggs.
Can anything be done to repair this (pictured, appreciate difficult to judge without seeing it first hand).
The con rod bearing journal appears to have bits of the aluminium con rod stuck on it, have done a bit of research and saw one bloke on YouTube had got it off with an acid of some sort.
The journal has a slight nick in it, the main bearing journal at the top of the crank does have some light scoring (it's a horizontal Briggs 125cc OHV) though it doesn't feel a great deal rougher than the tapered part.

Could it be saved? I bought a 2nd hand short block same engine code , but found it had a different crank where the blade boss mounts so having to try and use old crank in short block.

Cheers.

 

[dannyp]

clean it up with fine emery and measure it, it's fixable wether it's worth it. i woudl have thought you chould just get a crate motor for it, or even upgrade it and find a honda motor

personaly i can't stand briggs engines, much prefer the honda lumps, id actualy go for a honda clone over a briggs.

 

[pedrobedro]

Brick acid will fizz the aluminium off it then clean it with some WD and fine wet 'n' dry.

 

[wristpin]

As said, clean up the crank either with fine emery or by removing most of the transferred metal with acid. Thoroughly clean the crank afterwards and fill with SAE30.
Don't altogether agree with the above post on the Briggs v Honda argument . I had a garden machinery business for 30+years and we used to see far more Honda problems than Briggs. Their V twins on ride-ons were trouble , trouble, trouble. Too highly strung for the application.

 

[CompoSimmonite]

If it threw the conrod out the crankcase then surely you are going to need another rod & case at least so it makes sense to simply buy another whole engine.

 

[visor_down]

Thanks all I'll give the suggestions a go,anyone know what the tolerances are on these things, ie how far can you go with emery?

If it threw the conrod out the crankcase then surely you are going to need another rod & case at least so it makes sense to simply buy another whole engine.

When I say short block, I bought a whole 2nd hand engine minus ancillaries, initially thinking it would be straight swap of ancillaries , but found output end of crank is different (shorter) hence the need to swap crank from old to 'new'.
A new engine wouldn't be economical, the 2nd hand engine should of been a straight swap like I say, lesson learned! Wouldn't of bought it had I known.

 

[james butler]

there seems to be quite a few complete engines on eBay that may be worth a shout?
I've seen quite a few working mowers scrapped because of the chassis collapsing and wheels falling off so its a good chance you will find a working engine for not a lot of money.

 

[dannyp]

As said, clean up the crank either with fine emery or by removing most of the transferred metal with acid. Thoroughly clean the crank afterwards and fill with SAE30.
Don't altogether agree with the above post on the Briggs v Honda argument . I had a garden machinery business for 30+years and we used to see far more Honda problems than Briggs. Their V twins on ride-ons were trouble , trouble, trouble. Too highly strung for the application.

ok can we agree that ALL SMALL AIRCOOLED PETROL ENGINES ARE A PITA AND BEST AVOIDED ? ( however there are some exceptions that have redeaming features they normaly do silly revs and are atached to silly things )

 

[wristpin]

Thanks all I'll give the suggestions a go,anyone know what the tolerances are on these things, ie how far can you go with emery?.

All the clearances are published in the various workshop manuals but at this stage in proceedings I wouldn't worry, it's amazing what you can get away with and if you are not paying for labour , very little to loose.
Years ago we were asked by a charity whether we would repair a lawnmower for a young man with learning difficulties who liked mowing. What we were presented with was a decent Hayterette chassis and the remains of three Briggs engines. We just picked the best bits , did the valves etc and boxed it all together. It was still running when I retired five years later, so put the micrometer away!

 

[mike os]

Is the crank still straight?

 

[dannyp]

lawnmower engine tolerances, if it'll go round it's not to tight, if it dosent fall off it's not to loose

 

[dobbslc]

Spirit of salts will get the aluminum off the steel.
Used to use it to remove various bits of two stroke piston from barrels.....

 

[pedrobedro]

Spirit of salts will get the aluminum off the steel.
Used to use it to remove various bits of two stroke piston from barrels.....

That's dilute hydrochloric acid pretty much the same as brick acid.

 

[graffian]

That's dilute hydrochloric acid pretty much the same as brick acid.

Yep and it eat's steel and rusts everything nearby.
Clean the crank in hot caustic soda, it will look like new, and all the ali will be gone.

 

[Turbo]

There are plenty of 'parts or repair' lawnmowers on gumtree, etc with rotted decks but perfect engines for very small money. You might have to look at a few before finding a suitable engine but it's a few months before grass cutting season starts again!
Another alternative would be a visit to a lawnmower sales/service place, preferably a rural one. Most of them have lawnmower graveyards & you could get an engine there.

 

[dannyp]

might have a couple of half dead briggs engines here, sure its an ohv motor tho ?

 

[james butler]

might have a couple of half dead briggs engines here, sure its an ohv motor tho ?

all the brigs and stratton I've seen are side valve with push rods?

 

[penfold]

I currently operate a garden business, and I'd take a Honda clone over a Briggs (made after about 1986) any day of the week.

To me, the warranty speaks volumes - I've never found a manufacturer that fits Briggs engines offer more than 6 months for commercial use (3 months from Hayter), whereas Honda give 2 years.

I've got some 70s Briggs motors that are great, and a large pile of later ones waiting to be melted.

All my Honda kit is fine, even though it's seen more use.

There's B&S and there's B&S; the pot metal motors that are fitted to the kind of mowers sold for 99.99 are indeed junk and no time should be wasted on them beyond routine servicing. The iron barrel/steel sleeved industrial B&S are a different proposition and far more durable.

Yep and it eat's steel and rusts everything nearby.
Clean the crank in hot caustic soda, it will look like new, and all the ali will be gone.

This. Polish the journals with wet and dry, not emery.

 

[james butler]

OHV B&S:

View attachment 101522

blimey i stand corrected

do they do an upright cylinder engine?
ive wanted a crate upright engine for another project.

 

[james butler]

never mind awsered my own question
https://www.machinemart.co.uk/c/petrol-engines/