Thursday, February 23, 2012

Ice Auger

I picked up an ice auger from the dump.  It looks like I should be able to get it fixed up without too much work.

I like the names that they give these things.  It is manufactured by "Eskimo" and named the "Barracuda", a tropical fish?  If you look real close you can see that it is Model No. 9000B X.  Do you think that there are 8999 previous models that they made?

Tuesday, February 21, 2012

Outboard Motor Trim Pump

This is the hydraulic trim and tilt unit for a 90 hp Honda outboard.  The unit did not work, so I checked the resistence on the electrical leads and found that it was an open circuit (infinate resistance).  The most likely cause of this is stuck or worn brushes in the motor.  In this photo the motor has been removed and is laying on the work bench, the red stuff is hydraulic fluid where the motor mounts.

When I took the motor apart there was a bit of rust and corossion inside.  The brushes appeared to be OK, but one of the springs had rusted away. 

This motor is built with an internal overheat protection.  It is hard to see with all the rust, but there is two round electrical contacts mounted on a bimetal spring.  If the motor overheats the spring will open the contacts and stop the motor. 

The contacts did not work anymore, so I soldered a jumper wire across them.  There will no longer be an over heat control on the motor, but I think that it is unlikely to be needed in our cold climate.  I reinstalled this part and replaced the spring in the brush holder and the motor runs great now.

Sunday, February 19, 2012

Snowmobile Clutch Removal

I had a Polaris 550 snowmobile in the shop that I needed to pull the clutch off.  This first photo shows the back side of the clutch after the job is all done and it is laying on the work bench.  Sometimes I like to make the first photo something that will look good in the little thumbnail size where this blog is advertised over at the Rudstrom Family Blog.

The first step is to get the correct clutch puller and put some anti-seize on the threads.  There will be tremendous pressure on the threads when it is in use and this will help prevent it from binding up.

They are called clutch pullers, but a clutch pusher would be more accurate.  The tool threads into the clutch body and pushes on the end of the crankshaft.  This forces the clutch off of the tapered end of the crankshaft.

The bolt in the center of the clutch is removed and the puller is threaded in.  On this Polaris machine there is a hole placed in the body for this purpose.

The next trick is figuring out a way to keep the engine from turning over while you screw the puller in.  If you have an impact wrench you can simply buzz it in and the inertia of the engine is enough to keep it from turning.  On some electric start machines you can jam something in the teeth of the ring gear and hold the engine that way.

I have found that the best way to hold the engine is with a piece of rope pushed in through the spark plug hole.  Turn the engine so that it is a little way before top dead center, push a small rope into the cylinder until it is full, then turn the engine so that the piston pushes it against the head.

When doing this make sure that you don't start with the piston too far down in the bore or the rope may go out one of the ports.  If using this technique on a four stroke engine make sure that the piston is on a compression stroke so that the valves are closed.

This method works well on small and large engines.  I once used this idea to hold the crankshaft on the engine in my truck when I was trying to change a timing belt on the side of the road.

You normally have to screw the pull in very tight and when the clutch finally lets go it comes of with a bang.  Here is the end of crankshaft once the clutch has been removed.  The shaft is machined with a slight taper that matches the tapered hole on the clutch.  It always seems amazing to me how all the torque from the engine is transferred by the friction on those two tapered surfaces.

Wednesday, February 15, 2012

Exhaust Spring Tool

Most snowmobile exhaust systems are held together with springs.  The springs allow the the parts to move around with temperature changes and engine movement but always remain in tightly connected.

Removing and installing these springs is easy if you have the right tool.  Here are two spring tools that I made.  One of them is made from an old screwdriver that I ground two notches in the blade.  One is for pulling and the other for pushing.

The second tool is made from the wire handle from a 5 gallon plastic bucket.  The ell shaped bend on the end is originally from where the handle connected to the bucket.  It is just the righ shape to grab the end of a spring.  I put a piece of plastic fuel tubing over the wire to make a softer handle and then bent it into a loop.  This is my favorite spring tool.  It looks crude, but works great.

Monday, February 13, 2012

Yamaha Grizzly Starter

A customer brought in a Yamaha Grizzly that would not start.  When the start button was pressed nothing happened, not even a click from the solenoid.  The battery voltage checked out ok so I tested the power going to the solenoid coil.  A little probing around with a volt meter showed that the solenoid coil was receiving the start signal, but was not working.  The solenoid would have to be replaced. 

After determining that the solenoid was bad I wanted to check out he rest of the system so I jumped the terminals on the solenoid with a screw driver.  This test (which they actually recommend in the Yamaha service manual) can tell you a lot about the condition of the start system.  There are three possible outcomes of this test.  The most common result is no sparks and no starter movement - means that the brushes are worn out or faulty.  The second result is medium sparks and the starter turns - indicates the starter is fine but the solenoid is faulty.  The last result is lots of sparks but no movement on the starter - indicates that the starter is drawing a high amperage but cannot turn.

I found the last result, lots of sparks but no movement.  The next step is to remove the starter and see what is going on.  The plastic body work on the right side needs to be removed and the air intake hose on the clutch cover.  The first photo shows my hand reaching in to loosen the bolts.

Here is the starter sitting on the work bench.  I make a few reference marks on the motor casing before taking it apart.  These marks make it easy to get the end caps back on in the proper order and in the correct rotation.

Here is the starter with the end caps off.  The magnets are broken and the pieces were jammed in tight and preventing the rotor from turning.  I am not sure why the magnets broke.  One possibility is that the faulty solenoid prevented the starter from operating and someone decided to tap on it to get it going.  On a starter with wore out brushes you can sometimes get it to by giving it a few taps to loosen up the stuck brushes.  A few light taps are ok, but maybe someone pounded on it very hard.

Tuesday, February 7, 2012

Coolant Tank Repair

A friend brought me the coolant tank (reservoir) off of his Arctic Cat F6 Sno Pro.  One of the small plastic nipples for a hose was broken off.  The red arrows point to the nipple and the location that it is supposed to be connected.   A new tank is probably not to expensive, but would take several weeks to get here.

The plastic that these things are made from seems to be impossible to glue.  Luckily the area on the tank where the nipple was located was thick.  I decided to drill out the old hole and tap threads for a new brass fitting.  When tapping threads you must be sure to use the correct size bit, normally the size is printed on the side of the tap.  In this case I am tapping for a 1/8" pipe thread and the correct drill is 21/64.

Make sure that the tap gets started straight in the hole.  Pipe threads are tapered, don't run the tap in too far or the hole will end up oversize.  Stop and check the fit often.  A good rule of thumb is - 3 loose, 3 tight, 3 showing.  This means that you should be able to turn the fitting in three turns by hand, three turns with a wrench, and have three threads still showing when finished.

I applied a little bit of Leak Lock to the threads before assembling the parts.  Most standard water plumbing thread compounds are Teflon based and are not supposed to be used with petroleum products.  On anything involving oil or gas I use Leak Lock.

Here is the finished repair, a $3.00 brass fitting and 15 minutes.

Saturday, February 4, 2012

Row Boat Rebuild

A few years ago I built a 9' row boat for some friends of mine.  You can check out photos of the launching over on the family blog.

The boat has a few problems that I am going to fix up this winter.  The boat was put together with construction adhesive and drywall screws (it was all I had lying around at the time).  Over the years the screws have rusted and the glue has failed in some of the joints.  The paint is also flaking off the bottom.

I am going to tape all the seams, put a light layer of fiberglass on the bottom, and seal all the wood with epoxy.  That is how the boat should have been built in the first place.  The first step is to grind all the old paint off.  I give more updates as the work progresses.

P.S. this is not actually in my shop, I'm doing this project over in the school wood shop.

Friday, February 3, 2012

Shop Tip - Melting Snow

I frequently have to thaw out machines that are packed full of snow before I can work on them.  When the snow melts the water makes a big mess on the shop floor.

To avoid most of the mess I like to put a piece of construction type plastic sheeting under the machine.  I then roll the edges up to form a sort of dam and clamp the edges to the machine or some other type of support.  When the snow melts it is all contained on the plastic.  I then use a wet/dry type shop vac to suck up the water.