Low Pressure Grease Gun for Outboard Jet

How to Grease an Outboard Jet

An outboard jet engine can handle a great deal of abuse. However, there is one maintenance item that, if ignored, can result in a complete failure of the jet lower assembly. That single item is the main bearings for the driveshaft in the jet pump.

Those bearings require a specific water-resistant grease after each and every use. Every time the pump is submerged you must add new grease to the bearings to expel any moisture.  

Thankfully, the Outboard Jet lower unit comes with a zerk fitting on the side of the pump, which is accessible without the need for any tools or disassembly. This zerk fitting is sealed with a rubber vent hose and is used to grease the driveshaft bearings inside the pump housing.

Use a low-pressure grease gun

You absolutely must use a low-pressure hand grease pump like the Starbrite Handy Grease Gun when greasing an Outboard Jet. A standard grease pump has the potential to immediately blow the seals out of the bearing carrier.

Do Not Use a Lever Type Grease Gun

Starbrite Hand Grease Gun

Use the proper grease

The best type of grease to use in an Outboard Jet is Quicksilver 2-4-C. The previous grease specified was Lubriplate 630-AA. You may still see this grease type specified in older manuals, but the type specified by Outboard Jets was changed in a notice published on their website in March 2015.


The grease for lower-pressure hand pump style grease guns is like toothpaste. As grease is used from the tube you will need to slide the grease inside the pouch up towards the top. The method I prefer is to fold the bottom over onto itself and use a wood clamp to hold it in place.

Step by Step – How to Grease an Outboard Jet

  1. Remove the vent hose from the zerk fitting on the side of the jet.
  2. Place a clear sandwich bag over the vent hose outlet and zip it closed.
  3. Pump grease into the fitting on the pump using the low-pressure grease gun until old grease is forced out of the tube.
  4. Continue pumping until excess grease starts to exit the vent hose into the bag.
  5. Remove the bag from the outlet tube and inspect it for moisture. A small bit of water is normal. The objective is to purge any moisture from the bearings to prevent damage.
  6. Reconnect the vent hose to the grease fitting.
Outboard Jet Grease Port

How to detect seal failure

Inspecting the contents of the sandwich bag each time will give an indication of the conditions inside the bearing housing. An increase in the moisture content purged each time is an indication that the seal is beginning to leak. If the grease becomes a dark gray color the driveshaft bearing should be inspected.

On the opposite side of the jet pump from the grease port, there is a small weep hole. This hole is useful to determine if the bearing seal is properly functioning. If you see grease coming from this hole then unfortunately one of the grease seals has failed. This doesn’t mean you can’t use the jet anymore but you need to focus on having the seal and possibly the bearings replaced. If the seal has failed you will need to diligently purge water from the pump each time you use it.

Routine Jet Pump Maintenance

Regularly greasing the Outboard Jet pump will keep the bearing operational for years. Making it part of your routine to add grease after each outing will let you know the moment you experience any issues with seal failure. I keep a small container near my boat with all of the necessary equipment to grease the bearings. This small kit includes gloves, a grease gun, and grease. This makes the process very simple at the end of the day to grab up the kit and add in a little grease to keep the Outboard Jet bearings in good shape.