Actually when there are 4 other random players on your team, they are just as much to blame for your victories and defeats as you are. You're never going to win a game without other players assisting you, and you're not going to lose one without other players influencing the loss either.
Here's something to dwell on:
If you really don't belong in the elo you are in, then you are much better than the players around you am I correct?
This means, that out of 10 players ONE team will have a much more skilled player.
Which means the enemy team will have 5 players who belong the in their current elo with similiar skill levels,
While your team, will only have 4 players who belong in the elo assuming you really do not belong in the elo, and have skills more superior than the players around you.
Therefore, this means you have a much higher chance of winning than the other team and should win more games than you lose. If OP really does belong in 1400 + elo then he should win more games than lose with or without a duo partner and as a result of this he should climb elo without assistance.
This is only the case if he actually belongs in the Elo or not though.