Sometimes you just need things to suck, like your vacuum, your girlfriend, or your fluid evacuator. 

The Mityvac 7201 Fluid Evacuator Plus  is versatile siphon-like unit that can change from vacuum to pressure for evacuating or dispensing fluids with the push of a button. This functionality makes it ideal for draining tanks or reservoirs then pumping the used fluid out for easy disposal.
For extreme mobility, this unit utilizes a manual pump which means there’s no need for compressed air or an electrical outlet.  There are included accessories for draining engine oil, transmission or brake fluid straight from the respective dipstick or caliper.

This is especially useful for watercraft that can’t be drained without some sucking.  If you absolutely need to, you could use this on gasoline, but it will probably destroy the grommets and seals on the Mityvac. 

Features:

• Evacuates or dispenses at the push of a button
• Convenient manual pump operation
• Integrated 2.3 gallon (8.8 liter) capacity reservoir
• Large base with foot stabilizer
• Durable, chemical resistant polyethylene construction
• Automatic overflow prevention
• Quick-drain pour spout

Includes:

• Fluid evacuator/dispenser
• 0.23" OD x 5′ long (5.7 mm OD x 1.5 m long) dipstick tube
• 0.26" OD x 5′ long (6.6 mm OD x 1.5 m long) dipstick tube
• 0.41" OD x 5′ long (10 mm OD x 1.5 m long) main evacuation tube
• Tube adapters
• User manual (English/French/Spanish)

Specifications:

Reservoir capacity: 2.3 gallons (8.8 liters)
Max. operating temperature: 175°F (80°C)
Packaged weight:10.0 lbs (4.5 kg)
Size: 24" tall x 12.4" wide x 9.3" deep (610 mm tall x 315 mm wide x 235 mm deep)