Converting to premix....Help.

[Traps]

Hey all. I have never had any faith in auto mixers and I am keen to convert my 1997 GTX 787 to premix. Is it as simple as draining the gas and premixing to a 40:1 ratio or is there something else that I am missing. I have heard that the tank needs to stay in the ski because it still lubricates the gears. Is this true, if so, what needs to stay connected? Thanks for your time and help.

 

[El Toro 33809]

The rotary valve shaft is lubricated with the 2-stroke oil. It circulates separately from the injection system. You can remove the lines to the injector, the lines from the injector to the intake (cap off the nipples at the intake), remove the pump (cable too) and install the block off plate.

That being said, the injection system Seadoo uses is very reliable. If the cable breaks, if will go to the full on position, not starve it for oil. You may want to reconsider eliminating the injection system.

 

[Traps]

Thanks El Toro. Been doing a bit of reading and although the system seems to be reliable I have always had problems with plastic gears more that cable breakages.
I have read that I can leave the complete system in place, as I have no desire to remove any parts of the ski, but just remove the shaft from the pump and leave about half a tank of oil for it to carry on lubricating the rotax gears. Have you heard of this being done?

 

[El Toro 33809]

I personally haven't heard of that. Search around the forum some, or post that question in the 2-stroke PwC area of the forum. Good luck.

 

[Traps]

Thanks for your input. Much appreciated.

 

[Dr Honda]

Your oil pump doesn't have any "Plastic Gears" in the system. The 800 is a direct drive off the flywheel.

As above... the seadoo/Mikuni system is reliable, and in all my years of playing with them... all failures can be traced back to lack of maintenance. (Cracked hoses, plugged filters, etc)

If you want to remove it... it's your ski... do want you want. But, as above... you still need to leave the tank in the hull, and hooked to the center gears of the engine. The tank doesn't have to be full, and as long as the seals are good... the oil shouldn't be consumed.


Our help is to tell you to leave it on.


If you had a Merc boat... or a Yamaha ski... we would tell you to remove the system.

 

[Traps]

Thanks for your advice Dr Honda. I have read a few of your posts in here and respect the fact that you know a hell of a lot more than what I do about PWC. On your advice I thought that I would rather do a proper inspection of the system and make sure the previous owner had kept the maintenance up to scratch, I am an auto electrician/mechanic/hydraulic tech in the forklift industry for 16 years now so I can appreciate the importance of regular maintenance. When I pulled the pump off I found that the cable was corroded at the crimp and that the cradle it fits into is very badly corroded, a case of clean what you can see I would say. The hoses are not held onto the nipples by any kind of tie and they are very soft at the ends and hard in the middle, not healthy.
Living here in New Zealand things seem to be a little more expensive because of our location. I am trying to ensure that I will not have unnecessary failures as this will, without a doubt, cost a lot to repair.
Now I know where you stand when it comes to premixing, what I would like to know is that apart from plug fouling, what other damage can be done by premixing.
I must thank you for taking the time to answer theses questions, what I can only imagine, hundreds of times over and over again.

 

[Dr Honda]

No problems with the info.

Just an FYI... seadoo's need 40:1 mix with a good API-TC oil. (They don't like TC-w3 oil)

 

[Traps]

Thanks for that. You answered just as I finished doing all the work on my ski. I am going to order new parts for the auto lube because I do not trust the rusted parts and hard hoses one bit. I am going to order a new shaft too just to err on the side of caution. Normally it takes 2 weeks for packages to reach here so I will run it premix until then.
Got my oil from a Seadoo dealership so I am confident it is the correct type.

 

[racerxxx]

On a 787 you have to remove the plastic drive from the end of the crank. It only indexes of the flywheel nut, it will wobble like no ones business and possibly take out your pick up coil. This has to be removed period, if you want to be cheap you can use your pump as the block off, but you will still need to cap the injection nipples on the rotary valve cover. Plug the feed line to the injection pump, and leave the rotary valve gear lines hooked up or loop them together if you like. I prefer to leave the tank and the lines hooked up to them, but that plastic pump drive must go.

Sent from my SGH-T989 using Tapatalk 2

 

[Traps]

Hey racerxxx. I have removed the plastic drive for now. I have left the tank in place and the bottom line that goes to the gears attached to the tank with about a third of oil left in the tank. If I remove the drive, leave all other lines connected as is, would that work? I do want to reconnect the pump but would like to use the ski while I wait.

 

[racerxxx]

I guess you could, but if you have no faith in the pump just be done with it all together. Like I said, leave the line going to the engine (rotary valve gear, below the carbs) and the line coming from the rotary valve gear hooked up plug the one feeding the pump and go to an autoparts store and buy small vacuum port caps and make sure they fit tight and use a cable tie to hold them on. If you buy a proper block off kit around $20 it will come with the cover plate for the pump, nipple block offs, cable ties and short screws to hold the block off plate on. Drain the gas tank, then top it off to an even amount of gas then mix it 40:1 and rock and roll.