Prices for snowmobile repair are pretty much set, it's a seasonal cash cow so they're going to make their money while they can. Mark's prices are cheaper than a dealer but he's good so I pay the price, cheap repairmen give you what you pay for...been there done that!
Ask Mark. You're looking at a few hundred for his basic service to go through the machine and make it ready for you. Clean the carbs, change out the old gas and plugs, lube pivot points and stuff like that. Additional repairs add up quickly and you can have more in the machine than it's worth before you know it. But you'll be able to ride for the rest of the season and he stands behind his work. He's busy this time of year too, so you may not get your machine back for a while.
You might want to try running a can of Seafoam marine carb cleaner through and see if you can get it running better first. That stuff is amazing.
You say it starts but is hard to start. If you left fuel in it I would bet the idle circuit in the carb is the problem, gummed up form the old fuel. The idle circuit in a carb has some small holes, easily plugged up.
I would try the Seafoam and plugs first, especially if you know the plugs are old.
Put some Seafoam in it and get it started so it will run the fuel with the Saefoam through out the fuel system. Better yet if you can ride it to let the Seafoam clean it out.
I have 11 snowmobiles, of which 8 start and haul ass just fine. Most are from 1979-1987 that I got very cheaply, some for free. EVERY one of them required a complete and thoro going thru- basically tear em down to the frame and rebuild every component. Its the ONLY way to make them reliable again. Takes a lot of time- like 40 hrs per machine or more. At $100/hr thats $4000. Not worth it for a $300 machine. Gotta be able to do it all yourself. You tube is your friend-
If any of you guys are willing to help/show me some stuff, I would greatly appreciate it. I'm a fisherman not a mechanic, so I'm not very good at these types of things. YouTube is great and helps most, but basic knowledge is required for it to be applicable.
If you have the mechanical ability to replace the pull rope then you can change the plugs and check the spark plug gap. I use starting spray to help get things started and once it's running the seafoam should do the trick.
If your gas is old (smells like shellac) you really do need to drain it and put in fresh.
You tube has videos showing how to pull the carbs and clean the jets. It's not that hard but you may not have to do it if the Seafoam does it's thing.
You said you are a fisherman and not a mechanic but at a minimum you do need to be able to change plugs and know how to put on a spare belt if you are going to use a snowmobile for fishing. It's like being able to change a tire on your car if you're going to be driving -- it's just basic.