Why do you fill lower unit from the bottom?
Air…….it will take you forever to fill from the top due to all of the air that must be vented out in the process. When you fill from the bottom, with the top plug out, you force the air out as you force the lube in.
Can you fill a lower unit from the top?
Filling from the top down will not allow all the air to escape from the gear box The heavy gear lube will stop flowing down as cohesion from surfaces slow it down till it stops as the air wants to go out the top hole If you let it sit overnight all the trapped air would eventually make its way up to the top …
What are the seals on an outboard gearbox?
Some of the seals on your outboard’s lower unit include: 1 Shift oil seal and shift shaft plate O-ring 2 Driveshaft oil seal 3 Gearbox bearing housing O-rings 4 Prop shaft oil seal More …
Why do you need to change lower unit oil on a Mercury outboard?
Lower unit oil changes are an important part of maintaining an outboard motor. Changing the lower unit oil of a Mercury outboard provides the proper lubrication for the internal components of the motor, while removing normal shavings from the oil.
What should I do if my outboard lower unit is bad?
Before the water in the gear lube destroys the lower unit. There should never be more than 3/4″ of metal particles on your lower magnetic gearbox drain screw magnet. When you are examining the magnet, mash any of the contaminants in your hands. If it turns into a gray powder, you can completely ignore it.
Why is it important to maintain Mercury outboard motor?
Maintaining your Mercury outboard lower unit provides a peace of mind knowing that your boat’s motor will function efficiently when out for a day on the water. Lower unit oil changes are an important part of maintaining an outboard motor.
How does the gearbox work on an outboard?
The gearbox also dictates which direction the prop shaft and propeller rotate in. The drive shaft enters the gearbox and ends at a pinion gear. The pinion gear is permanently engaged with the forward gear and the reverse gear, so when the driveshaft is rotating, the pinion gear is rotating, and the forward and reverse gears are rotating.
How does the pinion gear on an outboard work?
The pinion gear is permanently engaged with the forward gear and the reverse gear, so when the driveshaft is rotating, the pinion gear is rotating, and the forward and reverse gears are rotating. Shims behind the pinion, forward and reverse gears keep the gears properly engaged with one another, with no play between them.
Before the water in the gear lube destroys the lower unit. There should never be more than 3/4″ of metal particles on your lower magnetic gearbox drain screw magnet. When you are examining the magnet, mash any of the contaminants in your hands. If it turns into a gray powder, you can completely ignore it.
What is the lower part of the outboard called?
The lower unit is also known as the gearcase. It’s the portion of the outboard that receives the rotation and power from the engine’s powerhead to transfer it to the propeller and prop shaft. The propeller rotates, which allows your boat to move either forward or backwards through the water.