Wow, you seriously need some help.
What's a Stall Team?
A stall team is a team that actually resolves into having very bulky Pokemons to wall take them down your foe's Pokemons through passive damage, like Toxic, Sandstorm etc...
Well, all I see is setup sweepers. Oh, and Ferrothorn is not a setup sweeper Pokemon.
You are using really good Pokemons, but you've got a harsh Fighting Weakness. 4 out of 6 Pokemons are weak against Fighting. I can hear Infernape Fest.
We will need to drop one of your Pokemons that is Fighting Weak and bring a Ghost-type Pokemon.
Then, your EV spreads. They look like VGC spreads. Use something a little more regular/
Team Changes
I suggest you to drop Gyarados & Bisharp, and replace them with Jellicent & Venusaur.
Jellicent and Venusaur are 2 Pokemon that are equally good stallers. Now looking into the comp, I can say there is practically no type your team is weak to, and haven't got covered.
Fire is covered by Heatran's immunity and Salamence & Jellicent's resistance to that type.
Fighting is now covered with Venusaur and Salamence's resistance, while Jellicent is immune to this type.
These 2 types were the most threatening.
Now I have a suggestion: Drop Salamence and use Dragonite instead for more bulk, since I treat your team as semi-stall. Or, if you no longer want to use a stall team, keep the Salamence but try Dragonite and select whichever is doing good for you. I'd normally have tested it for you, only if my Laptop wouldn't freeze when I enter Showdown.
Mamoswine
Your Mamoswine's EV spread is silly. Curse is as equally silly, so I'll suggest to drop it down and use a different spread instead.
Mamoswine
Item: Ice Gem
Ability: Thick Fat
EV Spread: 208 HP / 244 Atk / 56 Def
Nature: Adamant
Role: Bulky Attacker
Moveset:
- Earthquake
- Knock Off
- Ice Shard
- Icicle Crash
This Moveset is designed, along the EV spread, to make the most use of Mamoswine as a bulky Pokemon that can resist hits, while dishing massive damage in counter.
Against Landorus, for example, even with Intimidate, you can OHKO Landorus with Ice Gem boosted Ice Shard. You'll also OHKO 80% of the time Tornadus and offensive Thundurus.
Did I mention it resists Superpower from Adamant Landorus-Therian, and unboosted Draco Meteor from Latios?
Jellicent
Nothing in particular to say, except Jelly's mighty mustache, might typing and mighty defensive stats are absolutely, mightily mighty.
Jellicent
Item: Leftovers
Ability: Water Absorb
EV Spread: 252 HP / 36 Def / 220 SpD
Nature: Calm
Role: Special Wall
Moveset:
- Scald
- Recover
- Toxic
- Shadow Ball / Ice Beam
Jellicent's typing and stat distribution make it an excellent special wall. This set's focus is primary to stall, as the main objective is to tank hits, inflict status, and slowly wear the opponent down throughout the use of Toxic and Scald. Jellicent can easily switch on a physically based sweeper and cripple it with Scald/Recover spam. The choice between Shadow Ball and Ice Beam is relatively tough, it's down to preference. Whether STAB or coverage matters for you, try both and decide which is choice for you, like for Salamence VS Dragonite.
Venusaur
Venusaur is a perfect move. You can't go wrong with it in a stall team; it is the joker of jokers, the supremacy of stall. I can see the word STALL written on Venusaur, you can't fail if you have it in your team.
Venusaur
Mega Pokemon
Ability: Chlorophyll --> Thick Fat
EV Spread: 252 HP / 240 Def / 16 Speed
Nature: Bold
Role: Defensive Stall
Moveset:
- Giga Drain
- Sludge Bomb
- Leech Seed
- Synthesis
Here, you've got the wall nobody can put down. You'll most likely not use Venusaur against Heatran, Mandibuzz or Ferrothorn anyway. Giga Drain is Venusaur's main STAB move and helps in keeping its fighting conditions pristine, especially against powerful sweepers such as Landorus-Therian. Sludge Bomb is a good secondary STAB move that is mainly used to hit Flying and Dragon Pokemons, and it also hits most Fairy-types super effectively.
Synthesis is, sadly, Venusaur's only reliable and consistent recovery move other than Rest. What makes it unviable is low PP and ineffectiveness in most weather conditions but it is necessary for healing alongside Giga Drain. Leech Seed is a way like another to add recovery, because Venusaur is to be used by patient players who are good enough at predicting.
Heatran
Good Job on this one, Heatran is a great Pokemon. You can't go wrong without him on most teams nowadays, you need a counter or check to him in any team.
Heatran
Item: Leftovers
Ability: Flash Fire
EV Spread: 248 HP / 220 SpD / 40 Speed
Nature: Calm
Role: Specially Defensive Stall
Moveset:
- Lava Plume
- Protect
- Toxic
- Stealth Rock
You'll start off by setting up dem Stealth Rock on the field to threaten your opponent to constantly switch to keep your active unit in check, to stop VoltSwitch and for supplementary, cheap passive damage that can actually kill Mega-Charizard Y in two hits.
While Protect is silly in Singles, I consider it as your MVP in this moveset because it will gain crucial Leftovers Recover, scout opponent unit's move and stack up Toxic damage as well as being unexpected. Lava Plume is a solid and consistent STAB that will comes with a 30% chance to burn.
Ferrothorn
Ferrothorn is a known Pokemon. Since it entered the battlefield, in BW, it was already an iconic wall that could equally set up hazards and threaten every single Water Pokemon.
Ferrothorn
Item: Leftovers
Ability: Iron Barbs
EV Spread: 252 HP / 88 Def / 168 SpD
Nature: Impish
Role: Utility Stall
Moveset:
- Spikes
- Leech Seed
- Power Whip
- Protect
Very similar to the Heatran, here you got a defensive Ferrothorn that lays down Spikes for more passive damage, more VoltSwitch crippling and more prevention of check. Protect is here to make Leech Seed and Leftovers recovery stack up, and scout the opposing unit's skills and role. Once you got these informations, you can start dealing appropriately with the foe Pokemon. Power Whip is a powerful STAB move too.
Dragonite VS Salamence
Salamence is a Pokemon I detest. It's out of question, for me, to use one. I'd opt for Dragonite since it adds more bulk, over and over, and is too unpredictable to be predicted. If you desire to keep your Salamence, it is perfectly fine as is. If you are convinced to opt Dragonite, try out this one:
Dragonite
Item: Leftovers
Ability: Multiscale
EV Spread: 216 HP / 64 Atk / 228 SpD
Nature: Adamant
Role: BulkyRoost
Moveset:
- Roost
- Dragon Tail
- Extreme Speed
- Superpower
I can't stress enough on this Dragonite's usefulness. When I glance at a Dragonite, if facing somebody, I suddenly want to figure out what's the moveset. This Dragon Pokemon is an extremely versatile unit. Roost will heal your Dragonite and will keep it in virgin battle condition so it can keep its powerful skill, Multiscale, active. That ability will make fun of logic, even the mighty Kyurem-White cannot OHKO you with Blizzard boosted by Choice Specs. Dragon Tail will eliminate the opponent's Pokemon from the battlefield and will swap it with another randomly chosen unit out of the team. This particular ability will allow you to pressure your opponent and make him play as you want him to. It will furthermore damage the units, one after the other, of hazards. Keeping on doing that will make the impatient opponents want to surrender the fight. Extreme Speed will go out as priority and will wear down a previously weakened Pokemon. Superpower adds coverage.
I hope I have helped you. Feed me back!!
Sincerely, RecreativeReshiram