Blown engine; rebuild or replace with new

oldpilgrim · Jun 4, 2015

I'd take off the bottom to see the rod/crank.

ultrarunner · Jun 4, 2015

If I even need a replacement small engine... TBN will be my first post.

Around here the decks rust away long before the engines.

Bought my first power mower in 1980 from Sears... mowed rental property from sun up to sun down 1 day each week... never did anything special except oil changes and maybe a plug... still runs good... the deck is tin foil!

Got a 18hp craftsman with a Briggs... good unit... let my brother borrow it for an area at his ranch... might as well give it to him because the ruts and squirrel mounds sure have beat it...

Don't think these were ever made to cut grass up to 30" tall!

buickanddeere · Jun 5, 2015

apctjb said:
BuickandDeere; Thanks for the extensive list of options! Also good to know that the LX255 is worth investing the time and $$$ in. What engine supplier did you pull the data and prices from? Of the choice you mention do you see one as requiring the least modification or are all going to be pretty much the same?

If all things are pretty much equal would you go to the larger HP or does that just lead to other problems.

Thanks

smallenginewarehouse.com

RandyT · Jun 5, 2015

All of the engines listed will require a exhaust rebuild, All of the engines listed have the exhaust come out the right side of the head if sitting on the tractor seat, where yours comes out the bottom on your existing engine. There is also a 75% chance that you will have to modify the electrical system for any of the engines listed. I would go with a higher HP rating, mostly do to the newer engines just don't seem to have the same HP as the older engines.

apctjb · Jun 5, 2015

RandyT: Great advice; much appreciated. Would you anticipate that there are new mufflers that I could purchase that would work (attach to the side yet exhaust is in the same place on the bottom) or better off taking it to a welding shop modify the existing muffler to work with side exhaust port? I like the idea of having the added HP. What about going to a twin? Are they more reliable or twice the number of things to go wrong?

Kyle_in_Tex · Jun 5, 2015

apctjb said:
RandyT: Great advice; much appreciated. Would you anticipate that there are new mufflers that I could purchase that would work (attach to the side yet exhaust is in the same place on the bottom) or better off taking it to a welding shop modify the existing muffler to work with side exhaust port? I like the idea of having the added HP. What about going to a twin? Are they more reliable or twice the number of things to go wrong?

That 26 hp kawi has a muffler in the right location. Not sure if it will fit stock. You can buy a new pulley or have your old one machined out if the new shaft is too big.

KubotainNH · Jun 5, 2015

I posted your picture with some edits. Pull all the bolts that have a red line pointing to them, I'm sure there some I missed because I couldn't see them in the picture just remove them all around the circumference. Remove any rust/crud on the fatter part of the crank so the base of the motor will slide off. Then take a rubber mallet and tap the base off the motor so it slides off the crankshaft. The only thing I'm unsure of is if anything needs to be disconnected before the cover comes off. I see there's a small cover with 3 bolts, I don't know what it's for.

apctjb · Jun 5, 2015

KubotainNH; Thanks for guidance! Looks pretty straightforward. Going to give it a try this weekend. Will be interesting to see whats inside.

RandyT · Jun 5, 2015

apctjb said:
RandyT: Great advice; much appreciated. Would you anticipate that there are new mufflers that I could purchase that would work (attach to the side yet exhaust is in the same place on the bottom) or better off taking it to a welding shop modify the existing muffler to work with side exhaust port? I like the idea of having the added HP. What about going to a twin? Are they more reliable or twice the number of things to go wrong?

If you can get the right size pipe and have it bent correctly, Kohler does offer bare exhaust mounting flanges that you can weld pipe to. You may also be able to start with say a MTD exhaust pipe and then have it adapted to your existing muffler. Husqvarna exhaust pipes may be an option also. Just have to look around at existing mowers at dealers, etc and see what you thing will fit the best and go from their.

Single versus twin is not really a reliability issue as much as what engine you can fit under the hood, and take into account with a twin you will have to come up with two exhaust manifolds.

apctjb · Jun 5, 2015

Thanks to all for the post. Opened the case (see photos) and found a broken rod just above where it joins the crankshaft. No holes in the case and gears all look good. There is a 1/2" semi circle broken off the bottom of the cylinder sleeve (see pictures) which appears to be below the lowest point that the piston travels so perhaps not an issue. The crankshaft where the rod attaches seems moderately scored. cylinder, head, valves, piston, rings etc. all look very clean and not damaged.

So should I trash this engine and buy new or is it worth the time and $$$ in parts to rebuild??

ultrarunner · Jun 6, 2015

It would seem the crank is the biggest problem... piston and rod are easier to deal with.

Last time I priced a crank for a small engine it was like 75% of what the engine could be bought for if bought right.

Grinding undersized only works if the right bearings set is available... building it back to stock is another option... had one done back in the early 80's and it was $65 and was told they were giving me a deal.

oldpilgrim · Jun 6, 2015

I'd dump it based on the broken cylinder and shaft.

To rebuild, You'lld need to pull the head, remove the piston/rod, replace the rings, hone the cyl, turn/replace the crank, get new bearings, gasket set, get new rod, and hope the cyl doesnt become a problem.

cost would be a couple hundred or more.

Nope, a new chinese model would be my choice.

RandyT · Jun 6, 2015

I think you will find that the piston skirt gets into the area of the cylinder that is broken. If so it won't hold up. Only other option would be a block but that may be as much as a complete replacement engine. Even it you did rebuild it I would be finding out the reason behind the lack of lubrication failure.

apctjb · Jun 6, 2015

Looks like a new engine then. Oldpilgrim; can you elaborate on "new Chinese model"; what are the pros and cons and where to source one? From previous post there appears to be no direct drop in replacement for my engine although I did find a Briggs that has a John Deere conversion kit although its on the pricey side. What are the modifications which are likely and how much time and $$$ am I likely to face to get a new engine to work.

Thanks

buickanddeere · Jun 6, 2015

Wonder why the rod friction welded it's self to the crank journal ?

oldpilgrim · Jun 6, 2015

habor freight sells Chinese exact copies of Honda engines, for cheap. I have no idea if you can get one that would fit, but I'd look.

Kyle_in_Tex · Jun 6, 2015

oldpilgrim said:
habor freight sells Chinese exact copies of Honda engines, for cheap. I have no idea if you can get one that would fit, but I'd look.

I wouldn't say "exact". But cheap they are. If you get one, don't even run it until you change the oil. Then run the fresh oil for 10 minutes or more and change again.

Billrog · Jun 6, 2015

Not sure what size shaft your tractor takes but I bought a Honda industrial 20 HP 1" shaft from my mill $900 on sale.

KubotainNH · Jun 8, 2015

HF doesn't look to sell vertical shaft motors that are big enough. Plenty of horizontal shaft motors. 1" shaft seems to be common in the 500cc range. Maybe something like this? You may have to pipe the exhaust out.

Briggs & Stratton® 17.5 HP Vertical Shaft Engine, 500 cc - Tractor Supply Co.
vertical shaft from Northern Tool + Equipment

apctjb · Jun 10, 2015

Okay; have been looking at various engines that might work. Found a new Briggs 19HP Intek (built for John Deere and says JD on the engine) that has the same PTO shaft diameter, has a fuel pump and a 9amp charging system. The Kohler that I am replacing had a 15amp charging system.

My understanding is that the electric PTO clutch requires at least a 9 amp charge which the Briggs just meets but is less than what the Kohler had. Any opinions as to will this be enough? I doubt I will ever be mowing the grass in the dark and needing to run the lights and PTO at the same time...

thanks