Monday, May 25, 2015

Murray 12.5/40 Update

This tractor has been doing a lot of the mowing.  Burns some oil but it is managable.

Yesterday the deck got fouled with the rear wheels.  Turns out whoever removed the hood brackets failed to notice the same bolts held the front axle in place.  4 new bolts fixed that.

New air and pre filter.

Friday, May 8, 2015

Briggs 31X707

Scored another of the OHV single cylinder briggs variety.  Have not looked at it much but it is in the 31 family but without pressure lube or filter.

Took it to the car wash and removed the head.  Definitely a busted con rod.

 Cylinder bore is .013" in the wear axis top and .002" at the bottom.  I will know better when I pull the pan and get a reading on the virgin bore area.  So the block would need a rebore to be useful.  I would rather spend the money on one of the similar engines with pressurized lubrication and oil filter.

Unfortunately I got oil on the camera lense at this point.

The head gasket was not blown and came off clean.  Good enough for testing another engine but I am not sure if it would be dependable.
The outside was covered with oil so I am guessing they were topping it off frequently.

My guess is that it started using oil and got so bad they ran it out of oil and blew the rod.

This makes my 4th engine in this family.  3/4 have worn out bores.

Engines of the 31 OHV variety
31A good condition unknown history, found junked
31B worn bore 200 hours from a JD Zero turn
31C worn bore (but running) in craftsman DYT4000
31D no pressure lube, worn bore, busted rod, unknow history

Thursday, May 7, 2015

Briggs 28M707 1186-E1 9711197A

Landed another Briggs 13HP L head.   The spark plug looked very good.

It has a broken rod but there is only minor damage to the bottom of the cylinder.

I need to inspect for cylinder wall scoring in better light but I am thinking it is good.

The rod journal is covered with aluminum.   IRRC some acide maybe muriatic will remove it.
Cylinder is a bit on the oval side in that it is .001" in the virgin area. Taper on the wear axis is .004" for at total of .005"

Go-putz's engine is about .013".

I have been saving old ziplock back from the kitchen and have made generous use of them while disassembly.

The oil in this engine was approaching the viscosity of jello.  Not sure what was going on with that.

Plan is to rebuild this engine using parts from one of the other similar engine.  The original piston and rings will be retained and no boring or honing should be required.  I am not sure if it will go onto go-putz or the  Murray 12.5/40.

So I will need a minimum of a pan and head gasket.  But first I need to get the parts washer going.

Sunday, May 3, 2015

Murray 12.5/40's History

The world is even smaller in a small town. 

I needed to deliver a front axle to a friend's place. I hooked the two wheel cart to the 12.5/40 Murray and headed out. The friend told me he had once owned this Murray, he put the 18HP twin on it and that he had already given me the 12.5HP briggs that belonged on it! And the mower originally belonged to an elderly lady who lives about a block away from me.

The original engine needs a rebore but somehow having all the original bits make putting it back appealing.

This was actually my second attempt at delivering the axle today.  The first time I ran out of gas 1/2 way there and my wife had to rescue me.  (and even brought me a cold beverage too!)