Crosman offers a service to locate shops that repair older Crosman air guns and rifles. See the link below.
I have absolutely no information on a Crosman model 143. Are you sure it isn't a model 140 or model 147. I even searched the net and can not find anything on a model 143.
This rifle was made for sears by Crosman. It really is a Crosman model 400. Crosman has most all their Owner and Parts manuals online. See the link below.
This is really a decent looking rifle. It's modeled after a Savage lever action big game rifle. It was made between 1965-70. Crosman no longer offers parts for this rifle but they do offer a web page of locations that repair older Crosman air rifles. See the link below
I'm going to try and help you with an answer. I know for a fact that the 126.2830 was made by Crosman for Sears. All Sears model starting with 126.XXXX were Crosman models. My catalogue list the model 126.2831 as a model 180 Crosman rifle not a gun, and I think yours is a variation of that model. See the #1 link below to see if it is a match. If your is a Crosman model 180 rifle, then See the link #2 below. Crosman offers a service to locate repair shops that repair older Crosman models. Link #3 is a parts list for the model 180
Go to ( See the link below ) and find your parts and owners manual for your gun or rifle. Crosman keeps a web page for older airguns.
As far as I know there is no Crosman model 88. Daisy made a model 88. I've attached a Link to Crosman's list of Owners manuals for all their rifles. You are welcome to look at it and try to find a Crosman model 88. See the link below.
The Crosman model 761XL is designed to shoot BB's or any .177 Caliber pellet. These are the most common pellets you can find. Make sure you select .177 Caliber pellets.
Take the rifle to a gun shop so they can figure out what make, model and caliber rifle you have. There is no 84 caliber long rifle.
I believe this is a Crosman model 180 made for Sears under the JG Higgins brand name. See the Link #1 below for the owners manual. If this is your rifle then I suggest the following. Crosman offers a service to locate repair shops that restore older Crosman air guns.. See the Link #2 below for more information.
The Sears Model 42DL .22 caliber rifle was manufactured by Marlin Firearms, their Model 80. Check with Marlin for parts availability.
Professional appraisal
Basically impossible to do with just the serial number.