How Deep To Go On Rebuilding (Refresh?) A Briggs Engine?

[seagiant]

Hi,
Was given a L-Head Model 28 1997 12.5 Power Built Briggs Engine.

I have no idea on wear or hours used.

Was told engine ran when given to last Owner.

Wondering about best way to easily tell without running Engine...

On how far to go with the clean up or rebuild.

Engine has an Iron Bore.

Just refreshed a Briggs 3.5 HP Kool Bore and runs great.

Wondering if I can do the same with this engine?

 

[Scrubcadet10]

the first thing to do would be to get it (or attempt to) get it running so you can find out, does it have adequate compression? If yes. good. If No, why not?
So you get it running but it's knocking... what's knocking? is it the rod big end? wrist pin? Or it may sound tight, but it's smoking oil like crazy, you either have a hone and ring job, if the cylinder is not ovaled. Or you have a bore job, over size piston, and rings. Or you have worn intake guides letting oil past (if no seals are used)...
so the best thing to tell the condition of an engine... is to run it.
of course being a flat head, you can pull the head off easily and check the cylinder for scoring... that'll tell you a lot there.
Usually with older engines, i clean them up, get them running. if they run good with no leaks, or knocks. i let them be. I only repair when it needs it and repair what is needed.... i've learned the saying "Leave well enough alone" the hard way.

 

[seagiant]

the first thing to do would be to get it (or attempt to) get it running so you can find out, does it have adequate compression? If yes. good. If No, why not?
So you get it running but it's knocking... what's knocking? is it the rod big end? wrist pin? Or it may sound tight, but it's smoking oil like crazy, you either have a hone and ring job, if the cylinder is not ovaled. Or you have a bore job, over size piston, and rings. Or you have worn intake guides letting oil past (if no seals are used)...
so the best thing to tell the condition of an engine... is to run it.
of course being a flat head, you can pull the head off easily and check the cylinder for scoring... that'll tell you a lot there.
Usually with older engines, i clean them up, get them running. if they run good with no leaks, or knocks. i let them be. I only repair when it needs it and repair what is needed.... i've learned the saying "Leave well enough alone" the hard way.

Hi,
Thank you, I feel better now about not wanting to dive in and do a full rebuild.

I can pull the Head and check the Cylinder Walls, clean the top of the Piston and Valves if needed...

Will give me an idea anyway on condition.

Could lap valves while there and check/set Lash?

Also could drop the Sump Cover and clean everything.

Engine was sitting outside for awhile.

Thanks again!

 

[Scrubcadet10]

i generally dont Just lap valves, unless im doing other major work, since you have to use a lapping paste, its liquid sandpaper basically. you want to be able to clean thoroloughly afterwards.
as far as it sitting outside. pull the dipstick and drain the oil, if it looks milky, it's probably got water in it. if it just looks dirty, i would change it, run it for a few hours, then change it again.

 

[seagiant]

i generally dont Just lap valves, unless im doing other major work, since you have to use a lapping paste, its liquid sandpaper basically. you want to be able to clean thoroloughly afterwards.
as far as it sitting outside. pull the dipstick and drain the oil, if it looks milky, it's probably got water in it. if it just looks dirty, i would change it, run it for a few hours, then change it again.

Hi,
That is what I did with the 3.5 Kool Bore as far as oil and a clean up and it runs now like a Sewing Machine!

It was also a give me sitting in the Junk Pile!

Put it on a McLaws Edger Frame, and use it every week as I live in Florida, and Yard Work is all year long.

 

[Scrubcadet10]

thats cool!