OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs Sprint on a Husqvarna Lawn Whizz base

I recently acquired this Hasqvarna Push Mower that seems to be a pretty decent quality unit.
The mower is now running nicely and with a full service it will no doubt run even better. The only obvious fault was the starter clutch however that�s now working spot on after a little TLC.
Where I am after some assistance is with the blade bar. It is stuffed. See the photo�s.
I have tried searching through the outdoorking online store and cant find anything to suit. I have also searched ebay and no luck.
I am hoping someone can point me in the right direction as this will be a really good mower when its done. The frame and catcher are in great condition.

Try under Viking/stihl as these were sold under both brands.

Still no luck searching. Any other suggestions would be appreciated.
Is retrofitting a similar blade bar an option with a different boss?

Yeah, i had a look at the bynorm and GA spares catalogue and couldn't find anything remotely similar. Although from your pics its hard to tell what's wrong with the blade.

Retrofitting is not a problem but there are 2 main things to consider, cutting width and how high up the pan the new assembly will sit. We need to see the boss to see if it has a deep spacing or a shallow one. Judging by the 2 bolts in your photo i'd say at least 10-15mm beyond the bottom of the crank.
Also helps to know if the crank has 1 or 2 keyway slots as that will help eliminate the types of bosses we can and can't use.

Hey guys
It is a bar blade of a lawnmaster lawnmower made by Steelfort here in New Zealand.
The blade was used on the cheaper models instead of the usual disc with flail blades.
They made the mowers for Husqvarna and Viking before Masport starting making the Viking mowers.
You can buy the blades here in NZ from most mower shops and on-line.
This shop here has them and send to Australia if that helps there are several options of blades.
http://www.sesdirect.co.nz/lawnmower-parts/blades/lawnmaster-2097422689
Just scroll down and you will see the 3 bar blades.

Hope this helps.

Thanks for the help guys.

Theo, there is nothing wrong with a blade bar with the exception of a fair bit of wear.I get the drift you think it could be tidied up on the grinder and still perform well?

Or best to go with a new bar as VC Victa suggested?

Nothing beats the cut of a new blade but I think you can clean that up and save some money. It doesn't appear to be beyond repair.
The key is to go nice and easy on the grinder so it doesnt get too hot and compromise the integrity of the steel. It is a bar blade after all and unless it's bent, damaged or broken it's made to be sharpened.

Bar blades need to be sharpened regularly, and yours has been neglected: it looks very blunt. Remember to balance the blade as you grind it, and remember you must finish up with a straight cutting edge, not one that curves back as you move toward the tip.

Personally I do not regard bar blades as a competitive cutting system, compared with swing-out blades on a blade disk. The quality of cut is inferior, they get blunt too quickly, they are dangerous to use, and they cost too much to replace. My favourite mower is an early 1980s Honda, and it had a Ninja blade when I got it, but now it has a 4 blade disk system from an HRU model. The cut is just incomparably better, and it is a lot easier to maintain. Better yet, it was a straight bolt-on modification, using only Honda parts (which were junk from a dead mower). I don't know if there is a readily available conversion for your Husqvarna, but in my opinion it would be a considerable improvement if you find one.

Thanks Theo & Grumpy. The comments are appreciated. I will clean up the blade bar tonight and re-install it taking carful note about your comment about getting a straight cutting edge and not a curved one. I'll also ensure the steel doesnt get too hot.

I am curious regarding your comment about blade bars being more dangerous than normal setups and I'd like to understand a bit more about it.

I will give the mower a good test on the weekend and let you know how it goes.

Peter, the conventional blades are small, short, light, and pivoted at the blade plate. If one of them hits something it swings back, rather than having to cut through it or hurl it violently away. The bar blade is long, heavy, and not pivoted; it can only stop by stopping the engine, or by shearing the drive key. Such a violent blow is involved that it sometimes bends the crankshaft.

This does not mean that conventional blades cannot cause very severe lacerations if they hit a person, but they are unlikely to perform actual amputations of limbs, which a bar blade can perhaps do. It is a matter of the effective moment of inertia of the rotating object. The existence of a pivot close to the point of impact of the blade, means that a much smaller mass has to be stopped by whatever the blade hits. If it weren't for the pivots where the blade mounts on the blade plate, conventional blades would be just as dangerous as bar blades.

This can be fairly common with these blades. Sometimes the crank can be straightened, sometimes it can't.

I agree with all of grumpy's points regarding bar blades here!

FWIW, the first major local manufacturer to introduce bar blades to the Oz market was Masport, at about the same time they brought the Iron Horse 2-stroke engine on to the market, in the 70's.

A compulsory [but reasonably priced] special service tool, that their dealers had to buy at the time, was a 'crankshaft straightener'. It was basically a steel channel 'bolt-to-bench' base; with a guide rail and two loose vee blocks, a small screw press mounted above it, and a 'long lever' runout indicator.

Worked quite well, so long as the shaft wasn't too badly bent to get it out of the engine!

There are 'in-engine' tools to do this job available, these days - http://www.milfordpower.com/R1709-Mighty-Midget-Crankshaft-Straightener-p/r1709.htm

For sharpening these blades, do as grumpy says, especially the balancing bit. If using an angle grinder, a flap disc will give you less problems with heat buildup than a grinding disc, though it won't remove metal as quickly.

G'day Jaffa, I have recently sharpened and balanced one of these and it came up fine.
It was in the same condition as yours.
My method is to use a bench grinder and a nail I have hammered into the side of a cupboard to watch my balance as I go.
You can also use one of these below for balancing.

I use a screwdriver shaft through the central hole in the bar blade for balance, and a 14" flat disk (36 grit size) for grinding, because the very coarse grinding material reduces the heating of the steel. An angle grinder will also do the job properly if you are careful and go slowly. However in essence the rule is, you use what you've got. Just don't let the blade get hot. If it's gone blue, it's gone soft. Grinding off the blue doesn't grind off the softened part, the blue is just the oxide layer on the surface of the metal.

Thanks guys. Again I appreciate the pointers. I put the mower back together today and took if for a run in the long grass and it performed pretty well for an older unit. Starts first pull and only blows a little smoke on startup. I ended up sharpening the blade on my bench grinder as best as I could being very careful to ensure it didnt get hot. I took the softly softly approach.

The mower performed well but I didnt take the catcher with me. It took down some relatively high grass. Tomorrow I'll take the catcher with me to ensure it gives a nice clean cut before throwing some fresh oil into it.

The only down side I can say it the frame on this mower is a little rattly. I have tightened all the frame bolts and clips. It should be all good however I'll let you know.

This mower will now become a parts source and the base will be used once a replacement engine is found. Nevertheless I appreciate the pointers on this mower. No parts will go to waste!

It still mows ok but it has a massive rod knock. The rod knock was confirmed by a mate of mine who is a car mechanic!

Thread can probably be closed!

Thanks for the update, Peter. I rebuilt a Honda GXV120 engine a few months ago to eliminate a big-end knock, but that was a Honda, plus I wanted the engine for a specific purpose, and it only cost $5 for a bucket of used parts to do the job. Personally I'm not attracted to side valve engines, though non-Honda OHV ones are at least a bit interesting. Hence I'd have made the same decision you did on this one.

There are lots more interesting engines out there, and I'm sure you'll continue to find enough of them to satisfy you.