'84 Aero 50 Won't Start

[zaebra]

first post!

i re-acquired my '84 Aero 50 (NB50M) recently and i'm trying to get it back to running condition. it has been sitting in a barn for 6 years, but it "ran when it was parked". currently, it turns over but will not fire. i have a brand new battery with 13+ volts, fresh gas, fresh oil, new spark plug, and the air filter element removed to increase air flow. it is getting spark (i pulled the plug and it arced like crazy). i've sprayed a little starting fluid in/around the air intake and it did chuff like it was going to fire, but that was it. the plug appears moist, maybe wet, and it smells of gas. there is no gas smell coming out of the exhaust. there are no leaks anywhere. also, i'm not sure what position the throttle is supposed to be in when starting it, but it doesn't seem to matter at the moment.

now the bad part. the prior owner had a problem with the fuel petcock, so he ripped off the bottom of the diaphragm and had the gas on all the time to the carb, and then he parked it in his barn and left it that way for the last 6 years. i would like to replace the stock vacuum-operated petcock with a manual one (if i can find one cheaply, maybe a universal), but i'm wondering if 6 years of gas might have done a number on the carb.

i'm new at working on scooters/motorcycles of any kind, but i've been a shade-tree mechanic on my own cars for years. i've never rebuilt a carb before, so i'm a little intimidated with how finicky they are. i'm also trying to keep this project as cheap as possible, so i'm opting for refreshing/rebuilding parts over buying a new one, if i can.

i do have a small laundry list of other things to take care of (tires are 30 years old, ignition won't turn so it's hotwired right now, etc), but if it won't run, none of the rest of it matters. any help you guys n' gals can offer about getting it running would be awesome! the shop manual from the technical documents link has already proven very useful to help get me to the point i'm at now, but i'm just stuck looking at the carb and dreading the inevitable.

[Dr_Craw]

just cleaning out the carb will probably help, its really not that bad get a spray carb cleaner and pull the float bowl, then the jets, clean thoroughly, if you have compressed air, blow all the stuff out.
try not to run the engine without the air intake or exhaust these restrictive elements are part of the tuning of the engine.
just make sure that neither is actually clogged. (are you getting pressure out the end of the exhaust? it may be clogged)
one other thing to test is cylinder compression

[noiseguy]

You will want to replace the vacuum petcock with the right part eventually.

You need to remove and clean the carb. Mandatory in this case.

[zaebra]

are there any good instructions for cleaning out the carb? is it just a matter of carefully disassembling, spraying with carb cleaner and cleaning parts in a non-destructive manner, and then reassembling? i haven't ever tackled carb work on anything, so i'm hesitant to screw it up with a noob move or something.

[zaebra]

i haven't been able to find any instructions for disassembling the NB50M carb, other than what is in the shop manual linked on this site. any help with a link on that?

also, there are lots of forums discussing the use of carb soak/carb dip, and most of them say that the modern stuff you can buy is somewhat useless. many alternatives have been mentioned (lacquer thinner, oxy clean, combustion chamber cleaner, etc), but there doesn't seem to be a consensus. what would be the best soak for the scooter carb? also, would i only be soaking all-metal components, or are plastic and rubber ok to soak as well? sorry, total noob when it comes to carbs. gotta learn sometime!

i'm assuming that i'm making a record of the adjustment screws' positions and how many turns they are currently backed out by bottoming them out before disassembly, correct?