Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Picked up a beatup YS624W which needed work.  It came with a matted mouse nest in the tractor base and a worn through impeller barrel due to tossing rocks.  The rusted sections on the right and left of the barrel bottom are pushed out about 1/2 -3/4 of an inch.  The main drive gear support post and flange bearings were also worn (pictures below).

The impeller area diameter is only 10.5 inches and has a whole worn through.  The worn an pushed out sections are in the forward part of the lower barrel.  A sheet of steel was installed with rivets.  The machine is an impressive tosser and due to it's high impeller speed and powerful engine that does not sag much under load so able to keep up the RPMs.

A nice feature is a class viewing window to check the oil level.  Note the heavy cast iron oil catch whch is part of the bracket for the engine support mount.

The impeller arms are mishapen and the plate also distorted but not as bad as the picture shows.  The bent area is due to camera angle distortion.  Note that the impeller diameter is 10 inches.

Got the impeller back into reasonable shape and put on some Rustoleum.

The muffler was rusted but the metal solid so taken off, wire brushed and painted with hight temp paint. 

Muffler heat shield and air box covers painted.  Muffler in much better shape.

The engine sits on motor mounts about 1/2 in above the tractor base.  Two big rubber mounts on standoffs support the mounts which are connected to the engine cover by heavy brackets.  The left facing bracket has a rusted section at the L bend.  It's cracked at the rust area for almost it's entire lengts.  I've had about 6 of these machines and two have had broken motor mount brackets.  The other was on an 828 base bracket but both 6 and 8 hp machine use the same bracket.  2 out of 6 with broken brackets makes me suspect that the brackets may be a weak point in the design.  I did not notice on the other machine if the brackets were broken or cracked but they may have been. 

Note the brackets are mounted to the engine front cover which is made of very thick aluminum about twice the thickness of a Tecumseh cover.  It's also very nicely machined. 

Rear engine mounts.

The engine is raised up off the base about 3/4 of an inch, enough to snake a cable underneath.

Wheel drive gears are enclosed in a case which mounts to the tractor base side.  Note the grease is well spread on the gears.  There are voids in the case but the paste grease still got around somehow.  BUT, notice the center of the primary gear on the left.  It's mounted on a post with flange bearings on both sides.  The flange bearings were completely worn away.  There were no traces of the flange bearings in the case.  They had been ground to a powder and mixed into the grease. 

The gearcase cleaned up.  Note the roller bearings in the case.  You can see the primary gear support post is heavily worn out of shape.  The post is a tight fit so pops out and only a few dollar part.  The post may be a weak point in the design due to not getting any grease.  The flange bearings on the primary are very thin and do not have self contained oil so they don't get lub'ed.  The gase does have a gasket so fitting a new gasket and adding sealer might be tried in hopes it will hold liquid grease.  A screw hold can be added to the top for dumping in liquid grease.  The primary gear center section was worn so bad it had to be replaced, $89.  The teeth of both gears were fine so the paste grease fine there but did not help much for the center section and post.  All in all it lasted about 26 years so not bad but having lub would be better.

Nice engine with lots of power.  Note no crankshaft going out of the block.  The drive is from the camshaft PTO.  The engine runs at 4000 rpmon the 6hp and 3850-3900 on the 8hp.  The PTO runs at 2000 RPM.  The rakes I think run at 300 and the impeller 1400 or so.  These engines are very nice and do not sag much under load compared to a Tecumseh.  They are at least equal to a Honda GX and probably better.  Note the black rubber mounts on top to dampen gas tank vibration.  The tank has 4 posts and set into the tank mounts with hair pins.

Nicely machined head area.  The engine is getting rings and a valve job.  The engine compression was within spec but at the low end of its range but it had very good spring back.  It would be nice to get it peaked so with get some work.  The goal is to get it running well and compare it to a Honda 624.  The Honda 624 is a great machine and so is the YS624 but I think the Yamaha may have a slight edge.

When the piston is covered with my hand and the flywheel turned through a compression stroke the flywheel will bounce back and the spring back can be done once or twice more before it leaks by the rings. 

Liner inserted and painted. 

Lower bucket side distortion due to being thinned and pushed out by rocks.  The machine will clean up nicely but unfortunatly will have the rivets showing and the bulges.  

I>>>What was your cholce for a color match?

Dupli-Color DE1601 Ford Blue but DE1621 may be a better match.  Rustoleum has one close. 

 

>>>The wear in the gearcase is interesting.

    I had a Honda with the same problem.  The gearbox in the pre-hydro machines used the same design gearbox side mounted to the tractor section.  They used needle bearings on the primary gear.  The needle bearings were pulverized so no trace of them.  The only part of the needle bearings left was its outer case.  The spread of the paste grease was the same as the pictures above with plenty of grease on most of the gears but little at the center.

 

>>> Would a grease fitting on the gear case had helped to keep the center post and flange bearings lubricated? 

    It might by loading so much in there it will work around like up the gear spokes and case side wall to the middle.  Liquid grease would be better would have to be sealed well.  In both cases the gears lasted 20+ years.  It might be the grease stiffened and could not flow and creep its way around as in the early years.  ??

 

>>Do you think the Yamaha's side valve design is a match for the overhead valve of the Honda 624?

   It may be.  I’ve used a few Yamaha 624’s in the past and this year used a Honda 624.   The Yamahas were very impressive.  This year I got a Honda 624 and was not impressed at first but after several storms it’s also been very impressive.  It’s tough to remember in detail the performance of the Yamaha but I think it would match or beat the Honda.  Both engines are fantastic.  I don’t see complaints about either engine.  The GX series is well established.  I don’t see complaints about the Yamaha snow engines and there are plenty of 20+ year machines around with good engines.  The engine on mine was within spec.  The ring and valve work just an attempt to peak it.   You had an over spec reading on yours and I’m interested to see what the rings will do on mine.  I’m hoping for high 70’s or 80’s. 

Thanks for the analysis & "intimate" view of this machine. Nice to see  that some one else can see past the ugly duckling and realize there is still some swan left in the old girl.
Just wondering if that larger car style muffler helps contribute to the reduced noise of these machines?

Keep us posted on the engine teardown.  I would be curious to see what you find.  Will you need to replace gaskets for the head or can you re-used the one that came off?  I have always wondered if there was an easy way to remove the oxidation on the aluminum block to make it shine up.  On smaller (more accessible) parts I have used a soft bronze wire wheel and had acceptable results. But there must be some way to polish up the cooling fins. Maybe soda blast them? I've never tried that.

GtWtNorth>>>Just wondering if that larger car style muffler helps contribute to the reduced noise of these machines?

 

 

  It quieter than a Tecumseh.  It’s got a nice deep note that sounds potent.  BTW: the muffler is substantially built, heavy.

 

 

Underdog>>>Will you need to replace gaskets for the head or can you re-used the one that came off? 

    The rule of thumb is head gaskets should always be replaced.   A new gasket is on the way but I think the original could still be used.  The seems to be in perfect condition.  The mating cylinder and head surfaces are very smooth and clean and very much unlike what I’m used to seeing on Tecumsehs. 

 

 

>>>I have always wondered if there was an easy way to remove the oxidation on the aluminum block to make it shine up. 

 

 

   There are agents and processes but they are expensive and bothersome.  I don’t know of anything off the shelf that works.  I use any liquid and a wire brush.  The white stuff on carbs is a problem. 

 

 

>>>But there must be some way to polish up the cooling fins.

   Possibly Mothers but that’s a pretty bumpy surface and would probably look weird if you took the several hours to buff the fins out.  May be you could get it chrome plated at a hog shop. 

 

 

>>>Maybe soda blast them? I've never tried that.

   Soda blast?  I’ve never heard of that.  I’ll have to google it.

Anybody tried POR15 for this kinda stuf?  I found it amazing on rusty cars.  Does what all the other "rust paints" say they do, but dont.  There is even a heat resistant variety for things likee that muffler.

Search soda blast on youtube. If you have a compressor you can make a blaster pretty cheap for occasional use. Harbor Freight has a small one on sale for $99 right now. But aluminium oxidizes pretty quickly, it won't stay pretty for long.

>>>Anybody tried POR15 for this kinda stuf?  I found it amazing on rusty cars.  Does what all the other "rust paints" say they do, but dont.  There is even a heat resistant variety for things likee that muffler.

 

I’ve seen Por15 on a snowblower and it worked very well.  It’s expensive, requires steps and color limited but can take overcoating.  If you’ve had rust problems with the “rust paints” maybe you did not use them properly.  Rustoleum works fine.  How many of “all the other(s) have you used?  Which ones have you had problems with?

 

Bill_H,

    Never heard of soda blasting until Underdog mentioned it.  Thanks for mentioning the HF soda unit.  It caused me to google around.  There are a few videos of the HF units which seemed to work well enough.  I’ll have to check them out at HF. 

POR15 is head and shoulders above the rest.  It does not just put a coating over the rust, it chemically combines with it and prevents all further rusting.  I did some work on a rusted Isuzu Trooper seven years ago and it still looks like the day I put it on. Previously I did try various rust paints like rustoleum and several others.  With and without rust converters and priming first.  All failed within a year. usually much less given the severe conditions it was exposed to.  The POR15 is very different to work with because of its properties.  But it goes on thin and really isn't much more cost than the rust paints.  Once you develop the technique it is really quite easy  .But dont plan on reusing your brushes  and do wear plastic gloves lol.  The only real drawback is that its only available in black or grey.  If you want colours it does get pricey because you have to buy a special primer and overcoat to do it (although their advisor told me that you can very lightly overspray it with eneamel just before it sets and then apply a thicker enamel coat later, and this did work fairly well for me).  They also sell a heat  resistant paint that is quite good - put it on a high temp engine component also and its still there.  They also sell a POR15 paste in tubes that you can use to build up rusted areas - I tried this also on the trooper - takes quite a bit of prep work and is messy, but if you do it right it lasts as good as steel - and it has a tensile strenghth almost as high as steel too.

Would be ideal for the impeller, augers, and inside of the auger housing on a snowblower because these areas are exposed to sand and gravel erosion.

This stuff is really tough - I used to drive 70 miles/day on gravel which "sanded" the frame of the Trooper and exposecd it down to bare (and rusted) metal in just a few weeks.  The POR15, properly appled, is still there.

Woffie:  “Previously I did try various rust paints like rustoleum and several others.  With and without rust converters and priming first.  All failed within a year.”

Hard to believe.  In fact I don’t believe  it, sorry.

No one drives their snowbower down a gravel dirt road for 70 miles.

Por comes is 5 colors and can be overprinted with any paint >>per Por.   Call Por instead of fanaticizing facts.

Believe what you like troutie,  but I've been painting with rust paints for 30 years and for 7 years with POR15 and I know what works and what does not work.  And...read the post again - it was not my snowblower I was referring to, it was my Isuzu Trooper.  And people do use their bowers on gravel and EOD stuff full of sand, gravel and salt.