Thursday, March 31, 2011

Caterpillar D6

It didn't actually fit in the shop, but I did work on it.  It has some kind of problem with the steering.  Older dozers had simple mechanical clutches and brakes that were operated by big levers that you pulled on. They could be fixed with a crescent wrench and a hammer.  This machine has a new joystick type control.  I think there are a lot of complicated hydraulics involved.  I may to have to track down a service manual to figure it out.

Poulan Chainsaw

I had a small Poulan chainsaw in the shop recently.  These saws are inexpensive, but not very durable or long lasting.  They are so cheap that normally it is hardly worth repairing, for three hours of labor you could buy a new one.

The customer that brought me this saw complained that it did not idle and seemed to need choking every time it was started.  This sounds like a classic gummed up 2-stroke carb problem.   I started it up and noticed right away that the clutch seemed to be stuck and the saw did not run very good.  Normally the centrifugal clutch should release at low rpm and allow the saw to run without the chain moving.  On this saw the chain moved even when I pulled the start rope.

I put a little Sea Foam in the gas tank and let it sit for a while.  Well the Sea Foam was working its magic on the carb I check out the clutch.  When I pulled the bar off and removed the clutch cover I discovered that the spring in the clutch was broken.  I looked through my collection of broken saws and found a used spring that would work.

After putting the saw back together it ran great.  I am normally not a big believer in these "miracle in a can" engine treatments, but I have had great success with Sea Foam.  Anytime I have an engine that has been sitting unused for a long time and it does not run properly due to a carb problem, I put a little Sea Foam in the tank and it clears it right up.

Tuesday, March 22, 2011

Polaris Sportsman 500

I had my 2008 Polaris Sportsman 500 in the shop recently.  A few months ago the headlight that is mounted on the handlebars stopped working.  I did not worry about it too much, I just assumed that the bulb burned out.  Then last week the engine died when I turned the handlebars to the left.  I turned them back straight and it ran again.  I was able to make it most of the way home like this before the engine quite and would not restart.

When I finally got it in the shop and took the handlebars and instrument cluster apart this is what I found.  The lower arrow points to the broken headlight wires and the upper arrow points to the main switched power wire.  A few of the other wires also had cracks in the insulation but were not broken off. 

It was easy to solder the broken wires back together, but I am a little worried about future problems.  For some reason the wires seem to be brittle and cracking where they move with the handlebars.

Sunday, March 20, 2011

Tool Repair

My most used power tool is a 5" Milwaukee angle grinder.  It gets used for grinding, cutting, and sanding.  This particular Milwaukee model has a variable speed dial, but I never use it.  I always run it at full speed.

For the last few month the variable speed feature has been acting up.  Even though the dial is set for full speed the tool will only run at a slower speed.  If I turn it off and on a bunch of times it eventually works, but it has been getting annoying.

I decided to take it apart and see if I could bypass the variable speed unit.  In the above photo you can see the speed dial and the black electronic control unit just to the right of the screwdriver.

I made up a short jumper wire to bypass the electronic control.  I used crimp connectors that I also soldered.  I have found that this is the most economical way to make long term reliable electrical connections. 

Better connections can be made with high quality closed end crimps and the proper matching crimp tool, but these are surprisingly expensive and not readily available.  If you are working on marine wiring it is worth it.  For most jobs generic crimps that have been soldered work fine.

This photo shows the jumper wire installed between the switch and the brush holder.  I left the original wire in and simply taped up the end of it.  The hardest part of most power tool repairs is fitting everything back in the case.  It took several tries to get all the parts and wires in the right location.  It no longer has variable speed, but now it starts reliably every time I hit the trigger.

Saturday, March 19, 2011

Honda 420 - Complete

The Honda 420 that I have been working on for quite a while now is finished.  I used the parts and pieces from two wrecked engines to make one good one.  One engine had a cracked piston and a faulty transmission, the other one had a good transmission and a bad everything else.  Both engines failed from a lack of oil.

You can see the older posts about it here and here.

The whole project took about 25 hours of labor and $1000 in parts.  It runs great now, like these basic Hondas always do.  Most of the Honda models are not very high performance, but they all run great.

Thursday, March 17, 2011

Traveling - Elim

After spending the weekend in Nome I traveled on to Elim to do some work on the Head Start building.  The main project while I was there was to install a new oil supply line.  The oil line runs from a 500 gallon outside tank into the mechanical room and feeds two boilers and a water heater.

The oil line is made from 1/2" black iron pipe.  I brought my pipe threading equipment with me.  I have a large tri-stand type pipe vise, but it is too heavy to haul around on an airplane.  A few years ago I picked up this small pipe vise that clamps on the edge of a work bench.  I found a few scrap 2x4s and put together this table to work on.

This photo shows the new line running to the three burners.

Here is a close up of a filter and Tiger Loop assembly.  This is my preferred way to run multiple burners off one tank.  The Tiger Loop gives you the benefits of a two line system (self bleeding, greater lift, etc) without worrying about restrictive check valves or return line leaks.  The Tiger Loop is connected to the burner with flex lines that make servicing easy. 

Wednesday, March 16, 2011

Traveling - Nome

I recently spent some time in Nome at my friend Roger's.  You may remember Roger from my house jacking project this fall, or you may have seen him lighting a fuse over on my family blog.  Roger helped me out with the house so I came into Nome to help him out with a few mechanic jobs.

Roger has a Polaris 550 with a lot of hard miles on it.  Almost all those miles have been across bumpy tundra pulling a big sled.  When the machine was new Roger built this tow hitch and fuel can rack for the back.  It is made from 1/4" steel plate and it has held up fine.   Unfortunately the aluminum tunnel that it is bolted to is starting to crack in half.

I took everything apart on the back of the machine so I could straighten out the bent and broken tunnel.  Once I had that back together I welded up some longer braces for the tow hitch.  The hitch now has two pieces of flat bar that run all the way up to the foot wells. 

Saturday, March 12, 2011


I made a new sled for Harold to pull around with his snowmobile.

Wednesday, March 2, 2011

Honda 420

I almost have this machine finished.  Unfortunately I discovered that the fuel pump is missing and I had to order a new one.  That will take a week or two to get here.

When putting engines together like this you need to apply some type of sealant to the mating surfaces of the case.  The various manufacturers all recommend their particular brand of goo, but I never seem to have any Honda crankcase sealant part number 348576 or Yamaha special goop # 23-765, etc.  I always use Permatex Aviation Form-A-Gasket.  It has never failed me yet.