perhaps this will help.
1987 Sears Craftsman II 18 HP.- 917.254410
1989 Sears Craftsman II 18 HP.- 917.255919
as a guess i would say its a 1988 model. color is a silver-gray with red piping on hood and a black grill with red piping and the 44 inch deck was standard.
yes i have both and they are good machines but are noted for certain problems.
1. watch for fatique cracks on front axle, there not cast iron and will crack with age requiring plating on the bottom.
2. the 44 inch deck spindle units have no grease fittings, the pulleys are welded on the top and can't be removed so the whole assembly has to be replaced. i not sure you can get them anymore. simple cure is to remove them and drill, tap, and install grease fitting about 1 inch above blade.
3. starters can be a pain to get off these, look where its located at and you will understand.
4. fuel pump is located on a steel firewall between engine and battery, this is not a problem but the fuel line between the pump and engine will go bad with age causing little rubber bits to enter carb and plug main jet which leads to them starving for fuel. this a easy fix, remove hex cover cap on carb for main jet hit with carb and choke cleaner spray to unplug.
As far as durability goes my 87 still runs good but after mowing 2 and 1/2 acres for 20 years along with pushing snow in the winter the briggs 18 twin is about wore out. 10 ounces of oil used in 4 hours run time.
the 89 sears i picked up 2 years ago had less than 70 hours on it and had only been used for pushing snow in the winter, the deck was still new.
it is my current mower and runs great with no oil use.
they are good machines, the peerless rearends used in these are sturdy units that will take a lot of use and abuse. my 87 has 100lb weights on each wheel, 50 lbs on back of tractor along tubes in tires and they are calcium filled along with chains on the tires. I've never had a problem with it.
minor differences between the two.
87 has idiot light for low voltage.
89 has amp gauge.
87 has adjustment for main drive belt tension near hi-lo shift lever, the 89 has no adjustment.
one last thing drive belt to deck is easy to change, take about 4-5 minutes because they use a sping loaded tensioner.
if you got this for a good price you cant go wrong on these machines.