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.  

wolfee,

are you using that rust protection on your Honda snowblower?  show us some pictures of the rust protection on your beloved honda?

I did a lot of research on rust treatments over the years and tried several. My experience (I admit somewhat limited in the # of products I have personally used) seems to match up with what I've read online. POR-15 works. **IF** you properly remove the rust down to solid metal. But so do a lot of less costly treatments. Nothing works if you don't remove the old rust. I've had very good luck with the phosphorous based rust treatment products, both NAPA brand and Rustoleum seem to be the same. Clean the metal, removing all old rust. Brush/spray it on, let it dry. Hit it with a green Scotchbrite pad. Apply a good primer, then a good paint, you'll be at least as good as the factory finish. I've never had anything work for more than a year or two if I didn't clean off ALL the old rust first.

Well, I guess you can lead a horse to water, but you can't make him drink.

Bill_H>>> I've had very good luck with the phosphorous based rust treatment products,

   Same here.

 

Bill_H>>>Nothing works if you don't remove the old rust.

Yes, I’m mostly in agreement with all you said. There is embedded rust and minute pocked areas that full removal will leave a very distorted surface.  It’s too much to deal with for OPE.  There are also areas that are too cramped to get into to sand, grind or even wire brush well.  For OPE it’s impractical to get it all and patch or replace like you would on a car.  For embedded and other tough areas I found multiple treatments with rust products and brushing to be effective.  The cleaned/neutralized areas are then primed and painted with rust products. 

I’ve tracked a few snowblowers I’ve done and sold  The oldest is in it’s forth season.  The bucket inside was very bad.  It was sanded and wire brushed.  The surface was rust pocked so impossible to get at all the rust.  The inside was given repeated treatments of Must for Rust which is nothing special and like the rest.  The inside was given a few prime coats then coats of paint, both Rustoleum.  So far the paint has held up.

What I have found is rust products will not act on rust the same way all the time.  The metal used by various manufacturers is not the same and the character of the rust is also different. 

 

NASA has found Navel Jell to be useful and used it on its supersonic wind tunnel. The reason for the choice was similar to what the average person would use.  Navel Jell worked, it was cheap and easy to use.  The other products that did a better job were eliminated for cost and difficulty of use.  For OPE it’s a great treatment for up to 6 months because of it’s protective coating or the coating can be removed for painting.  They also used Rust Converter.

 

A decent rust info link is:

 http://www.metalwebnews.com/howto/rust/rust.html.  <<For the catatonic, the link must be cut and pasted.

Bill_H,

   I tried a soda blaster lashup with the compressor, airgun nozzle, tube and box of cooking baking soda.  It cleaned up an engine a bit and did remove some light rust.  No bad given the setup.  It was very messy though.   With the right soda and a better setup like the low end HF units it would probably be useful.

   The parts came is so work progressing on the 6hp rebuild.  Both the cam and the crank are on nice roller bearings.

  

Nice supports inside.  The crank cover has a lot of meat and much heavier than a Tecumseh cover.

Tecumseh 7hp on the left, 6hp Yamaha on the right.  The lobes are about the same size as a Tecumseh but the gear much bigger.

The internal supports are at least twice as thick as a Tecumseh and the finish much smoother.

Pistons are the same diameter.  Again much niger finish on the parts.

The bore is pretty smooth.  Note the wear is not front to back across from the skirts as is usually found.  The scuffing is on the side probably due to the cam being the driver.

The poston moves in bore very easily compared to any other Tecumseh I've worked on.  That may be due to the rollerbearings and better maching (I've never worked on a Tecumseh with roller bearings.  Postons are usually hard to get out of the bore.  It usually requires using a soft pine stick to push the piston out of the top of the bore.  The Yamaha piston came out easily with pusing up with my hand.  The difference was interesting.  The engine had an oil change before disassembly and filled with synthetic.  I'm not sure if that made the difference or better machining.  The bore still has lots of cross hatching so I think I'll do the cross hatching for the new rings by hand with very fine grit paper. 

   One other interesting thing was it was after the rod was taken out the bottom part of the rod was very difficult to get off.  It was held on by fit and the suction of the oil.  Tecumseh lower rods sections always just fall when the screws are loosened.   Big difference and probably due to better metal and machining.

These are great images.  Much better than looking at the Yamaha parts diagram.  What did the valves look like? Will you be replacing the rings and if so will you go up a size?

Looking good Trouts,

What kind of metal did you use for the patch?

Did you "wet seal" the patch in to keep water from accumulating between the patch and skin?

Friiy

Underdog>>>What did the valves look like?  Will you be replacing the rings and if so will you go up a size?

 

   The valves were good on the leakdown test.  The seats and faces were good also.  The lapping was a touchup lapping. 

The rings were replaced with standard rings.  All the internal measurements were within spec.  The engine was an ok engine and within spec but the compression reading on the low end of the range. 

When apart I put my palm over the bore and worked the flywheel to judge springback, that would be in the reverse direction testing for suction loss by the rings, the springback was pretty good.  I could work the flywheel a few times before loosing suction.  With the new rings it would spring back 4-6 times. 

With the old rings the compression was 58psi and within range.  With the new rings and about 30 minutes of breakin it’s 80psi.   The engine got an oil change at about 3 minutes or run time and another at 10 minutes.   Fairly cheap 15-40 used for breakin.  The engine has about 30 minutes of runtime and will get an oil change today which from here out will be synthetic.

By the way, the local Honda dealer has a device for converting the LA LB type of designations to the standard belt size designation. 

 

 

Friiy>>>What kind of metal did you use for the patch?

   A sheet of 1/8 steel riveted in.  Not the best but I’m not setup for metalworking. 

 

>>>Did you "wet seal" the patch in to keep water from accumulating between the patch and skin?

No, I used up all of that good glue you sent up on the Honda fixup.  I’ll have to live with the voids and go with the drain hole at the bottom.  The fit was pretty good as the metal in the barrel area was still mostly there and no out of place or round like the Honda repair.  I was going to get extensions welded on the impeller arms but the fit was close enough to the barrel that I dropped that.

 

The engine is done and mounted on the tractor.  Yesterday the new drive gear and bearings went in and the rest of the tractor parts installed.   There’s just the bucket to go back on maybe today.

Trouts, interesting seeing the Tecumseh and Yamaha side by side.    I believe I read that the Yamaha is around 25 years old but what is the approx age of the Tec?

35 worthy and honorable years. 

My brother runs a few 6hp's that are 45 years old.