Fish or cut bait?

[radnoyes 0]

 

 

New owner of a 1990 520H - thought I got a good deal at an auction last month (didn't follow my own advice of "never buy a used lawn mower), but low and behold I couldn't pass on it.  $650 for the tractor with 48" deck, one stage blower and chains.  1200 hours on it.  It started & the onan 20hp sounded pretty good - it was dirty but everything was there. 

 

Brought it home & cleaned it up -found some electrical that had been cobbled together-  several melted wires that got to close to the shield.  Patched that up & seemed to be running great - mowed 2 acres in no time.  Noticed that it was surging at high rpm, so pulled the carb/intake & gave it a good cleaning & installed new plugs.  Here's where trouble began.  Noticed the old rear plug was gunked up bad - as in no way it was firing.  Installed new plug, mowed again, no problems but still had some surging at high rpm.  Pulled the new plugs & had spark, but obviously was not firing on the back cylinder.  Checked compression - none.  Great.  Never had a twin cylider sound that good with only one firing.

 

Pulled the engine, heads were carboned up some, but not terrible.  Dropped the pan and the connector rod for the rear was in several pieces/diced/minced/pureed (I'm a chef at my real job).  Pushed out the piston & it had a chunk missing out of the side as well. - "Crap" was my response.

 

Advice needed: I did not pull the crank (never done that before & do not posess the tools or time to do it), Crank, other piston/arm & interior of cylinder visually look fine - no dings/scratches/gouging.  Can I get away with installing a matching piston/arm and putting this thing back together (hoping for 5-6 years of mowing), or should I cut bait & part this thing out?  Guessing taking it to a shop for entire rebuild will be $800-$1K - not willing (or have the money to) put that kind of cash in it.

 

Best tractor I've ever ridden (when it ran).  Any advice appreciated.

Edited July 26, 2014 by radnoyes

[305 380]

not familiar with the motor , but if it was mine and the crankshaft looked and measured good and the cylinder wall was ok i'd put in  new rod/piston/rings and give it a go.   how much are those parts?

[radnoyes 0]

If I need to buy them new, we're talking 350 to 400 bucks because the new pistons/rods are slightly different weight wise than the old.  I hope Boomer will be able to give me some insight on finding a used one that will match.

[Tim Bergfeld 55]

Boomer is amazing with those I was looking at a ingersoll and he knew everything I needed to fix it sounds like you got the same issue here except you need a piston too

The wolf

[radnoyes 0]

Just got off the phone with Boomer (who is awesome by the way, thanks for your help) & he helped me track down a piston/rod & the gasket kits I'll need to repair it.  Looks like a $200 project, hope it takes off.  Boomer claimed the rod likely failed because of poor lubrication (this rod is at the end of the line).  I'm thinking I need to check the oil pump over before I put it back together. 

 

Any way of testing the pump or is a visual check enough?

Edited July 26, 2014 by radnoyes

[Tim Bergfeld 55]

Boomer is like oz the great when it comes to engines I hear he is to engines what chuck Norris is to bad asses lol

The wolf