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JET PUMP MAINTENANCE

MODIFICATIONS AND UPGRADES

My Yamaha's jet pump clean out plugs/ports are stuck or sticking-how do I get them out or fix them?

What needs greasing in the drive train on my Yamaha Jet boat?

There are a few places that need grease, here are a couple of threads that cover the two main grease points (front and back)
  1. Bearing greasing-Cone Bearing breakdown, Cone bearing maintenance, Cone bearing and steering cable replacement Bruce's cone bearing replacement https://jetboaters.net/threads/changing-yamaha-jet-boat-pump-duct-housing-bearings-and-switching-to-oil-bath-lubrication.10155/page-3
  2. Intermediate bearing greasing, intermediate bearing replacement
  3. Video of the process of lubing the intermediate bearing /// edit - he advises to just pump grease until it comes out, this is contrary to most JBN opinion which is just give it 2-3 pumps as this is only a water block and not a lubrication issue (the bearings are sealed) ///

Besides those, all the linkages can use grease. The service manual shows all the possible points. I hit up the external linkages by pulling back the rubber boots, wiping on grease and sliding the boot back on.

Here is a thread that discusses what type of grease to use:
https://jetboaters.net/threads/yamaha-marine-grease-a-what-is-compatible-replaceable.1490/

How to pull your jet pump / Something stuck in my pump-engines don't get to full rpm

We often pick up/suck in stuff into the pumps, and this will cause all sorts of problems. Regardless of the model of jet boat, the first thing you need to do is get a good look/feel in the pump to ensure you have everything out. If you are on the water, this isn't always easy, and you may have to take tbe boat out of the water.

If you get it out of the water, look both from underneath, and open up the reverse gate and examine from behind with a good flashlight. Even a tiny piece of hard wood between the housing and the impeller can cause a problem.

If that fails and you are sure there is still something in there, then you need to pull the pump off. This sounds like a daunting things to do, and I thought so too until I did it for the first time. It is EASY. On a Yamaha it involves the removal of 5 bolts and one clip fitting. The only challenge some have had is if the shaft is stuck.....mine wasn't and came out easily. This may be more of an issue for salt water boaters???

Here are some links to threads that discuss this problem for Yamahas
Boat test video explaining the pump system
https://jetboaters.net/threads/boattest-com-talks-through-exploded-version-of-yamahas-propulsion.12972/#post-226278


How to dis-assemble Jet pump video, and photos
  1. I think I have something stuck in the impeller
  2. Easy trick on how to clear debris from your intake while on the water
  3. Damaged impeller linings
  4. Golf ball stuck in impeller!
  5. Photos of stuff stuck in impellers
  6. How to clear your intake grate
For Scarab/Chaparral pump disassembly
https://jetboaters.net/threads/sucked-in-the-tube-rope.10148/page-2

How to adjust your Yamaha jet pump gates

If you feel some vibration or chatter in the throttles or steering wheel, you may need to adjust your pump gates.
  1. How to Adjust reverse gates if your throttles chatter or your boat creeps forward to hard. Another thread with info on adjusting reverse gates.

How to clean out Yamaha intake screens or strainers

This is something you should check annually to ensure that there is nothing obstructing flow. You can verify this buy looking at your "pee holes", but they could be clogged themselves. Regardless, here is how you do it:

  1. How to clean intake screens or strainers

Yamaha's Bulletin on how to maintain your clean out plugs

My Jet drive pump wear ring shows wear-what are my options?

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