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

Homelite 20042A, 25cc

It was a problem getting the ring in because the bottom of the bore flares out.  You can't use a ring compressor.  I put the top of the piston in the bore then tried pushing the ring in with the tip of a pick.  In the process the ring broke.   What's the way to do it?

Where should the ring gap go?  Is it centered on the longest section of uninterrupted wall?

The crank weight has 11 degrees stamped on it.  How is the timing set?  I have not taken off the flywheel and assume it only goes in one way but not sure.  There is no key shown on the exploded view. 

I'm not familiar with Durafix but it sounds like it might be similar to Alumiweld. That's available at Harbor Freight and also has Youtube videos about it. The cool thing about Alumiweld (it's really brazing not welding, BTW) is if you assemble the thing and then use it, you can disassemble in the future as it won't stick to the steel bolt.

Bill_H,

    They are the same type of rods. 

    I think what you said was if you aluminum welded (low temp braze) around a bolt then the bolt can be backed out as the weld filler will not stick to the bolt.  Just getting familiar with the terms but I think that is due to the wetting action which is the bonding (wetting) of the filler to the welded stock.  The temp of the steel bolt would be higher so no wetting (sticking).  The bolt could be welded around and backed out. 

   There were a few videos of making a threaded stud.  A puddle of filler was melted onto an aluminim piece and a nut placed on top.  The inside of the nut was then filled with filler and when cooled the nut backed off the filler making a threaded stud on the piece. 

    Possibly an experienced person could build up the broken ear with or without a bolt inplace.  If without then the hole could be drilled and tapped or run a nut and bolt through.

     One interesting video had a block put in a oven to get it to 200 degrees then reparing a crack.

   

Bill_H,

   I picked up some alumaweld rods at HF but have not tried to use them yet.

Borat,

    The broken ear on the head was glued with JB Weld.  I let it dry for a several days then tried pushing hard up and down on the ear it's holding.  That's impressive as the two glue surfaces on the ear are very small.   I think it will hold the screw torque and probably be ok when vibrating under load. 

Good to hear you fixed it with the JB Weld.  That stuff is indispensable.  I was at camp for a few days and had to use it several times for an assortment of fixes.  Amazingly tough stuff.

Have you got that little engine running yet?

   No, the ring has not shown up yet.  I'd like to check the end gap when the ring comes in but don't have any specs.  I suppose it does not matter.  If it works fine and if not I keep it for parts.

   I'm just about to order rings for the Toro Powerlite 3hp.  Waiting until I do a bit more work on it to make sure I don't have to order anything else.  That one will be interesting as I've never worked on one with needle bearings and don't look forward to the re-install. 

   Many years ago when I was a kid my farther rebuilt the 7hp Merc engine for our hydroplane.  I remember the needle valves and him having some difficulty with them but he got'em in and the engine ran fine for many years after the rebuild.  It was interesting as he was a drugest and I never saw him work on any engines or OPE before or since.  His interest was woodworking but he would tackle anything and usually pull it off. 

   The ring came in and installed.  On screwing on the head the glued ear broke off.  The ear section contained half of a screw position.  I think the mate of the ear to the rest of the head ok but when screwing in the screw the ear broke.  It went in with resistance.  There was probably glue in the thread area and caused too much pressure on the ear.  The other head screws were put in and the section by the ear covered with glue along with a large section of head to crank.  Glue now runs from the head through what’s left of the screw hole over to the crank section.  The glue section then is massive and covers the head and crankcase area.

 

   It starts and runs so if the glue and the other screws hold the head in place it should be a viable engine.  I’ve got a trimmer with the same engine so will probably swap them and keep the original as a spare.  The engine had very low compression and now gets 120psi.   The purpose of messing with the engine was just to get experience with two strokes.