Bent crankshaft

[Dave Liquorice]

Damn 'n blast. Hit one of the larger rocks (bed rock...) in the "lawn" with the blade of the rotary mower the other week. Sheared the locating pins on the diecast boss, neat I though saves the engine.

Got a new boss and blade and fitted them, started it up and boy is there a lot of vibration. Check the new blade for balance OK. Dreaded thought output shaft bent, mower up on blocks, engine started. Oh dear... there is the shaft wobbling nicely by about 3/16". The B&S

10D900 series engine is "lumpy" and hunts but then it has no load, with the blade fitted and a short run of mowing it didn't seem to bad considering the vibration...

What does the panel think are the chances of:

a) Straighting the shaft in stitue. b) Other engine damage.

[Dave Baker]

Nil

Possibly to the crank bearing but you'll find out anyway when you strip it.

Dave Baker - Puma Race Engines

You find somebody to love in this world you'd better hang on tooth and nail - the wolf is always at the door. (Don Henley - In A New York Minute)

[Dave Liquorice]

I think Mr Baker's response of "Nil" sums it up having hit the end a few times with a lump hammer this afternoon.

I guess it's now down to the economics of the cost of a new crankhaft (+ engine gasket/seal set) , a new/refurb engine or a new mower... Anyone any idea of the costs of those?

At least with the last two options I'll have this engine for spares, it's only run for about 30hrs. Was new last year, changed the oil at the end of last season (black) and after half a dozen or so runs this year it's still lovely and clean when I dip it. B-(

[Capitol]

You've got a chance, done it with a large compressor which fell off a trailer onto it's flywheel! Regards Capitol

[Capitol]

ps, also seen it done with a 50MW alternator shaft! Regards Capitol

[N. Thornton]

Hi

I'd want to use something a lot more precise than a damn lump hammer. I've strightened all sorts of things up, but I wouldnt think of doing it with a hammer, you need controlled.

At the end of the day if it runs, all you need do is minimise the damage, no need for perfection. - having not seen it I might be missing something of course. Some say I am anyway :)

Regards, NT

[Dave Liquorice]

Well I agree but the hammer was available. If I had some form of hydraulical ram and strong mounting for the ram and the shaft. I'd get a gasket seal/set and take the shaft out but I don't have such sophisticated kit. I might enquire at the garage in the village.

With it spinning round with a 18" dia blade bolted it will have to run pretty true or the vibration will knacker (if it's not already) the bottom bearing/seal. AFAICT the bend is at the point where the shaft comes out of the crankcase. The shaft is vertical, about 3" long 1" dia and underneath the engine: -----+ +----- \ \ \ \ \_\

[SpamTrapSeeSig]

Which/whose engine is it?

In the past I've found that makes a huge difference in getting spares (and to the parts cost). Our Tecumseh 2-strokes on the Flymos were very hard to get bits for, but the later Briggs & Stratton ones were fine. A Tecumseh 'short' engine was available (cylinder piston con-rod and crankshaft/case), but hardly economic. We went that route once and the following time changed the mower :(

Regards,

Simonm.

[SpamTrapSeeSig]

My Land Rover expert locally has a hydraulic press, as most places do these days. He uses it for separating components, and straightening things. It's very powerful, very controllable, and, with a pair of V-blocks, ought to do just what you want.

Regarding gasket kits, whatever's wrong with Cornflakes packets?

Regards,

Simonm.

[Ian Smeaton]

==========================

Hi Dave, I've just bought a mower from Homebase for 99ukp. It has a 3.75 HP Briggs and Stratton engine. Is the hassle worth it?

Cheers,

Ian

[Dave Liquorice]

Self-propelled and 18" cut? Self propelled is essential to get up the hills and even to push it along the "flatter" bits. 18" cut is the minimum reuqired having had this one for a season if I was to buy again I'd seriously look at something bigger. I very much doubt that spec is available for =A399.

[Dave Liquorice]

Briggs & Stratton 10D900 series.

There are a number of "Authorized Registered Service Dealers" and a couple of "International Master Sales and Service Dealers" up so I'm hopeful that actually getting parts won't be a problem, the wallet damage may well be.

[Dave Liquorice]

I'll bear it in mind, village garage is the next stop I think. A tenner to straigthen the shaft is worth it. We have old cornflake packets, though looking at the Illustrated Parts List the gasket is available in 3 thickness's presumably to adjust the endfloat on the shaft.

It on a Qualcast but the engine is a B&S 10D902 model 0128.

[SpamTrapSeeSig]

I well understand :(

Our B+S haven't failed yet, so I haven't had cause to investigate spare parts places. I wonder if a semi-industrial outlet (agricultural machinery specialist?) might be a cheaper bet than a lawnmower repairer

- if they sell B+S engines for other machinery, e.g. compressors and small gennies. Only a thought...

Regards,

Simonm.

[Grunff]

Sure, but are the engine swappable? £99 for a new 3.5hp B&S is less than you'd pay from a main B&S dealer.

[Dave Liquorice]

Thats a point but 3.5hp would not have the grunt. This engine 4.5hp...

[Dave Liquorice]

On Sun, 13 Jul 2003 21:51:45 +0100, Andrew Heggie

Probably would being a 10D900 series. 132 not bad, cheaper than a new mower, just...

[Chris Oates]

Thats a point but 3.5hp would not have the grunt. This engine 4.5hp...

fit a Turbo

[Chris and Patsy]

Dave

The wife did the same thing to our 5hp B & S mower a couple of years ago, I was quoted around £75 for a new crank ! I stripped the engine down and the workshop where I work tried straightening it but it was too far gone. I then happened to be down our tip (do I mean recycling centre ?) and spotted an old mower with a same series engine, got it for a fiver. This engine was far more worn than mine, the crank bearings where scoured but I swapped the crank over and its still running fine now.

Chris

[Dave Liquorice]

I want it to mow the lawn not race. B-)