Tuesday, July 10, 2012

Yamaha HO four strokes Jet Boat Engine Flushing?

2006 Yamaha SX230 twin High Output four strokes JET BOAT


  • Owners manual for YAMAHA SX230.
  • Where are exactly Flush hoses located.
  • How to Flush Engine.
All three topics are discussed below with Appropriate solutions for you.

ISSUE 1: Owners manual for YAMAHA SX230

Regarding obtaining manual.You can get the manual online.Either you can view the PDF format of manual online or you can order 1 set of manual.

Option 1:Get your manuals from Yamaha Motor Corp US.
Here you can actually view the owner's manual on line without buying it, or you can order them from on line, or go to a dealer and order them.
Here is a link to the on line owner's manuals:
Then insert the particulars for your boat, 2006 SX230.If you need to get manual for any other Yamaha Jet ski or boat that also you can view or order here.

Option 2: This is the link for buying manuals on line from Yamaha. It is probably marginally faster for you to get your manuals if you order them on line as opposed to ordering from a dealer.
The common truth is Yamaha do not stock manuals with them.But  when ever they get an order, Crestec, the company that Yamaha uses to produce the manuals, prints one for them.And Yahama delivers it to you

ISSUE 2: Where are exactly Flush hoses located.

On most of the Yamaha Jet Ski models the flush hoses connect to fittings on the starboard side alongside the engines.Also in the manual its shown.From where to obtain owners manual,i have already provided.

But for your Yamaha jet ski model the Flush hoses are not located alongside the engine.

The flush connectors on the SX230 High-Output jet ski boat are located inside each of the rear corner storage bins. Its a black screw cap that undoes to reveal the bayonet fitting supplied in the Yamaha service tool kit.
These are fitted to red hoses which drive the back of the engine block and connect by way of Y connectors into the water cooling system.

ISSUE 3:  Engine Flushing on Yamaha Twin Strokes Jet ski boats:

First why you need to flush the engine?
Because you only need to flush them if you ran them in salt water.

Second use correct procedure and steps to flush the engine.

The step by step detail is as follows:---

1. Engine on (Start Engine)
2. Water on (Full Blast)
Flush for 15 minutes
3. Water off
4. Evacuate exhaust system of water (Rev engine a few times till water quits dumping
out the exhaust)
5. Engine Off.

These are the 5 key steps to complete the Engine Flush procedure.



The starboard engine hose on your Yamaha jet ski is too long and this many a times get  caught in the final drive coupling causing damage and I suspect allowing water to leak into the engine compartment.
 This hose is way too long and looks as if it can be re-routed over the final drive which would assist in stopping it from being caught up. If the hose is damaged then you can cut the damaged section of pipe out of the line and simply reconnect to the Y feed without the need for replacement of complete hose.

OTHER possibility that can cause or let the water in the engine compartment is, NEVER-EVER run the water with the engine off. This water will enter your engine and create such problems.
 If you have outboard experience, it is the exact OPPOSITE of flushing an outboard. There is no rubber water pump impeller on a Yamaha jet boat engine, which is why outboards require starting the water first. Also the exhaust system design is different between a jet boat engine and an outboard. The design of the jet boat exhaust will let water get into the engine if it isn't running when the water is.And here is where the problem starts.


Yes there are more possibilities that can cause water getting in to the engine compartment problem.

First make sure the jet pump clean out plugs are installed properly.If they are not installed properly then they will blow out.
Also if you notice that water getting into the engine from underside.Then I suspect the water you got in the bilge (engine bay as you called it) was from below the floor.

WHY this happens?
It happens because,when the plugs blows out, the water gets inside the hull and then once you start moving the boat, it enters the bilge.
For this reason there are there are drain plugs in the center of the bilge area. On some cases the owners dont install this drain plug.But its suggested to install it.Normally you would want them installed so what you experienced doesn't happen. They are supposed to be used for draining the bilge if necessary, so under normal operation they should be installed.If this drain plugs are not installed in your case then please get it installed.

Also one more possibility is not connected on blocked  external hull drain plug.
The external hull drain plug is located in the middle of the transom.

The external hull drain plug in the middle of the transom, is located way underneath the back of the boat.
To see this drain plug you will have to get down on your knees .This is  because it is so far in front of the back of the boat.Assume back of the boat as an overhang, and further forward in the center and down low there is another vertical surface that contains the drain plug. Make sure that is in while doing your pre-launch inspection.If this plug is not connected properly then remove it and reconnect properly.

This details will help.

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