diff --git a/src/pocketmine/inventory/Fuel.php b/src/pocketmine/inventory/Fuel.php
index 30249cb2d..1885fb533 100644
--- a/src/pocketmine/inventory/Fuel.php
+++ b/src/pocketmine/inventory/Fuel.php
@@ -26,29 +26,28 @@ use pocketmine\item\Item;
 //TODO: remove this
 abstract class Fuel{
 	public static $duration = [
-		Item::COAL => 80,
-		Item::COAL_BLOCK => 800,
-		Item::TRUNK => 15,
-		Item::WOODEN_PLANKS => 15,
-		Item::SAPLING => 5,
-		Item::WOODEN_AXE => 10,
-		Item::WOODEN_PICKAXE => 10,
-		Item::WOODEN_SWORD => 10,
-		Item::WOODEN_SHOVEL => 10,
-		Item::WOODEN_HOE => 10,
-		Item::STICK => 5,
-		Item::FENCE => 15,
-		Item::FENCE_GATE => 15,
-		Item::WOODEN_STAIRS => 15,
-		Item::SPRUCE_WOOD_STAIRS => 15,
-		Item::BIRCH_WOOD_STAIRS => 15,
-		Item::JUNGLE_WOOD_STAIRS => 15,
-		Item::TRAPDOOR => 15,
-		Item::WORKBENCH => 15,
-		Item::BOOKSHELF => 15,
-		Item::CHEST => 15,
-		Item::BUCKET => 1000,
-
+		Item::COAL => 1600,
+		Item::COAL_BLOCK => 16000,
+		Item::TRUNK => 300,
+		Item::WOODEN_PLANKS => 300,
+		Item::SAPLING => 100,
+		Item::WOODEN_AXE => 200,
+		Item::WOODEN_PICKAXE => 200,
+		Item::WOODEN_SWORD => 200,
+		Item::WOODEN_SHOVEL => 200,
+		Item::WOODEN_HOE => 200,
+		Item::STICK => 100,
+		Item::FENCE => 300,
+		Item::FENCE_GATE => 300,
+		Item::WOODEN_STAIRS => 300,
+		Item::SPRUCE_WOOD_STAIRS => 300,
+		Item::BIRCH_WOOD_STAIRS => 300,
+		Item::JUNGLE_WOOD_STAIRS => 300,
+		Item::TRAPDOOR => 300,
+		Item::WORKBENCH => 300,
+		Item::BOOKSHELF => 300,
+		Item::CHEST => 300,
+		Item::BUCKET => 20000,
 	];
 
 }
\ No newline at end of file
diff --git a/src/pocketmine/inventory/SlotType.php b/src/pocketmine/inventory/SlotType.php
index f8439f3cf..0f4297f06 100644
--- a/src/pocketmine/inventory/SlotType.php
+++ b/src/pocketmine/inventory/SlotType.php
@@ -24,7 +24,7 @@ namespace pocketmine\inventory;
 /**
  * Saves all the information regarding default inventory sizes and types
  */
-abstract class SlotType{
+interface SlotType{
 	const RESULT = 0;
 
 	const CRAFTING = 1; //Not used in Minecraft: PE yet
diff --git a/src/pocketmine/item/Item.php b/src/pocketmine/item/Item.php
index baea79cb9..0018a57ec 100644
--- a/src/pocketmine/item/Item.php
+++ b/src/pocketmine/item/Item.php
@@ -556,13 +556,13 @@ class Item{
 
 	final public function getFuelTime(){
 		if(!isset(Fuel::$duration[$this->id])){
-			return false;
+			return null;
 		}
 		if($this->id !== self::BUCKET or $this->meta === 10){
 			return Fuel::$duration[$this->id];
 		}
 
-		return false;
+		return null;
 	}
 
 	/**
diff --git a/src/pocketmine/tile/Furnace.php b/src/pocketmine/tile/Furnace.php
index f16ea7d62..0456e3d40 100644
--- a/src/pocketmine/tile/Furnace.php
+++ b/src/pocketmine/tile/Furnace.php
@@ -180,9 +180,9 @@ class Furnace extends Tile implements InventoryHolder, Container{
 		$product = $this->inventory->getResult();
 		$smelt = $this->server->getCraftingManager()->matchFurnaceRecipe($raw);
 		$canSmelt = ($smelt instanceof FurnaceRecipe and $raw->getCount() > 0 and (($smelt->getResult()->equals($product, true) and $product->getCount() < $product->getMaxStackSize()) or $product->getID() === Item::AIR));
-		if($this->namedtag["BurnTime"] <= 0 and $canSmelt and $fuel->getFuelTime() !== false and $fuel->getCount() > 0){
+		if($this->namedtag["BurnTime"] <= 0 and $canSmelt and $fuel->getFuelTime() !== null and $fuel->getCount() > 0){
 			$this->lastUpdate = microtime(true);
-			$time = floor($fuel->getFuelTime() * 20);
+			$time = floor($fuel->getFuelTime());
 			$this->namedtag->MaxTime = new Short("MaxTime", $time);
 			$this->namedtag->BurnTime = new Short("BurnTime", $time);
 			$this->namedtag->BurnTicks = new Short("BurnTicks", 0);
@@ -197,12 +197,11 @@ class Furnace extends Tile implements InventoryHolder, Container{
 			}
 		}
 		if($this->namedtag["BurnTime"] > 0){
-			$ticks = (microtime(true) - $this->lastUpdate) * 20;
-			$this->namedtag->BurnTime = new Short("BurnTime", $this->namedtag["BurnTime"] - $ticks);
+			$this->namedtag->BurnTime = new Short("BurnTime", $this->namedtag["BurnTime"] - 1);
 			$this->namedtag->BurnTicks = new Short("BurnTicks", ceil(($this->namedtag["BurnTime"] / $this->namedtag["MaxTime"] * 200)));
 
 			if($smelt instanceof FurnaceRecipe and $canSmelt){
-				$this->namedtag->CookTime = new Short("CookTime", $this->namedtag["CookTime"] + $ticks);
+				$this->namedtag->CookTime = new Short("CookTime", $this->namedtag["CookTime"] + 1);
 				if($this->namedtag["CookTime"] >= 200){ //10 seconds
 					$product = Item::get($smelt->getResult()->getID(), $smelt->getResult()->getDamage(), $product->getCount() + 1);
 					$this->inventory->setResult($product);