Newbie with questions, White GT 1855

I love my GT-1855. I grew up with it over the years, was 12 or so when we got it and I'm 32 today and have it.

Some parts are hard to come by or are starting to be hard to find. My dealer when we bought it put calcium in the rear tires and eventually ate through the rims. The tires and rims are are discontinued and impossible to find. I lucked into finding a GT-2055 with a blown engine and bought it for 300.

The model on my GT-1855 is under the seat on the tractor, centered between the brackets for the seat. The GT-2055 I got for parts I never could find it, they have a different seat on it and I think it was on the seat itself or something as I looked the whole tractor over and nothing.

The engine, the serial on mine is on the left side of the engine if your sitting on the tractor. Its by the sparkplug to the front on a medal strip I believe.

Here is probably the manual:
http://manuals.mtdproducts.com/mtd/GetFile.do?filename=770-8568j.pdf

Oh be careful if you have the 50" deck and ordering the spindles and blade adapters. For some reason if you order the correct part number they send you half inch versions instead of the 1" version you need.

I think these are correct but double check before using if they are needed:
748-0300 1" Blade Adapter
918-0118 1" Spindle Assembly


And some other info:
My Tractor Model 998 1994
Model: *144-998-190

Engine repair Manual I think is item number: 272144

Engine Motor Oil - SAE 30wt
Oil Filter - Wix 51348
Briggs: 842921 replaced by 491056.
FRAM: PH3614
Purolator: L10241
K&N: PS-1002
Spark Plug - 491055 * .030" *or *0.76mm Champion RC12YC
Fuel Filter - 493629
Air Filter / Foam - Filter:394018 * *Foam:271271
Transmission Hydraulic Engine Oil - 20w Straight Viscosity SE, CC, CD - Tractor Supply
Transmission Oil Filter - FRAM PH16 * * 727-0162
Ignition Switch - 725-1396 - About $8
Solenoid - 725-1426 - About $13
Wheel Weights: 723-0366 190-784-190 OEM-190-784

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Mower Deck:
Old part numbers for Mower Deck Blade Adapter and Spindle:
748-0300 1" Blade Adapter
918-0118 1" Spindle
742-0171 17” Deck Blade Oregon Part #: 98-037
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50" Deck 190-993
12" Moldboard Plow 190-920
48" Tandem Disc Harrow 190-921
Spring Tooth Cultivator 190-922
54" Snow Blade 190-985
45" Snow Thrower 190-990
38" Rotary Tiller 190-960
Rear Chains 190-965
75lb each Wheel Weights 190-784
All Weather Cab (Model 850)
8 HP 38" Tiller
Front Loader (Allied Equipment)
Backhoe (Allied Equipment)