New to Me 1993 Sea Doo GTX with a 587. Bogging

[rok99]

I bought a 1993 GTX and it is my first jet ski. It was $1800 canadian with a trailer I am mechanically inclined but far from a mechanic...

I first had this jet ski out for about 1.5 hours and drove it at low throttle the entire time between a boat launch and my dock. I noticed it bogging down but after that ride saw the jet intake had a bunch of sea weed in it. I was scared taking it out for the first time and open ocean- I did not crack the throttle much during that first ride.

Onto the issues... I've had it out for a 25min and two 15 minute rides after that. The last two times i've really noticed the ski bogging down. Basically even when i pull the throttle to be more open, it does not respond or even dies out as i open the throttle more. The other issue is I've noticed a lot of oil in the hull. The previous owner was using synthetic sea-doo 2 stroke oil but i've swapped for the brown sea doo xps oil. I was thinking of adding UV dye to the oil to ID the leak. The fuel gague and speedo also do not work. Can you 3d print a new paddle wheel? There is also a decent amount of water in the hull that i've noticed though i'm not sure if some is from waves hitting the rear vents.

I've done a few things. The jetski was having trouble starting and I erroneously replaced the starter before realizing that the ground cable was not crimped properly. So, the jet ski has a new starter (Amazon- but i've kept the original starter), battery, solenoid and ground terminals.

I can't pinpoint the oil leak but it almost all appears to be the previous owner's oil. I don't see any of the brown oil in the hull.

More important though to me is the bogging. I've ordered:
1. Mikuni Carburetor rebuild kit (and tools- some pins, JIS screwdriver bits, and assembled a pop off tester). I did not buy needle valves... should I?
2. Fuel filter replacements
3. Fuel float replacement (fuel gague does not work)
4. New oil filter for when i replace oil lines
5. A carbon seal kit.

However I really want to just replace all of the oil and fuel lines to be done with it. I note that the sea doo manual says the oil lines are 6, 8 and 12mm and that the fuel lines are 6mm (is that ID or OD?). Issue is that I (A) don't know how much bulk length to buy of each (10ft, 25ft) and (B) am struggling to find suppliers in Canada.
I'm not sure what other cheap and easy maintenance I should do so that I can just enjoy this machine without worrying about it dying out. Any advice is appreciated.

 

[mikidymac]

Yes, you need to buy the needle and seat and make sure all parts are Genuine Mikuni.
Oil system has to be flushed and new oil filter installed whenever changing oil brands.
Carbon seal isn't used on your generation of ski, it uses a carrier bearing.

The only oil lines that need to be replaced are the small 3/32" ones from the oil pump to the intake manifold.

All fuel hose is 1/4". The vent lines don't need to be replaced.

Change the jet pump oil and inspect the wear-ring.

 

[rok99]

Yes, you need to buy the needle and seat and make sure all parts are Genuine Mikuni.
Oil system has to be flushed and new oil filter installed whenever changing oil brands.
Carbon seal isn't used on your generation of ski, it uses a carrier bearing.

The only oil lines that need to be replaced are the small 3/32" ones from the oil pump to the intake manifold.

All fuel hose is 1/4". The vent lines don't need to be replaced.

Change the jet pump oil and inspect the wear-ring.

Thank you for your reply, Mikidymac.

I did get a genuine mikuni kit. I've struggled finding the 2.0 needle and seat online though. I guess it is 100% necessary to replace the needle instead of just clean it?

I didn't fush the oil system having not realized that the previous owner was running the XPS synthetic as he only mentioned that it was XPS, and, the oil tank was emptied. Hoping it is not a huge issue. I will replace the oil filter asap.

I guess I will have to return the carbon seal as the parts desk at my sea doo dealer is quite crap at identifying parts for pre 96 skis. I went home with a cartridge style oil filter from them until double checking against my photos of the engine. Should the carrier bearing or any other seals be replaced to ensure that water isn't entering the hull?

On the topic of hoses. Is 1/4 & 3/32 the ID or OD? Is it better to use 1/4" or metric 6mm? And what type of hose should I buy and of what lengths? I prefer something available at an auto parts store, as, I can get pricing at cost.

Thank you again, it really helps

 

[burtshaver2021]

And before anything take a compression test to see where you are at

 

[mikidymac]

XPS oil can be mixed with other XPS oil so you are fine there but yes change the oil filter and replace them small 3/32" oil injection lines.

Yes, you must replace the needle and seat.
Genuine Mikuni...
Amazon.com: Mikuni 14-1077 Needle Valve 2.0 : Automotive

Yes, return the carbon seal. You should be able to just add a couple pumps of grease to your carrier bearing, don't go crazy or you will pop the seals.

1/4" ID Standard automotive fuel hose 25' is plenty.

 

[rok99]

XPS oil can be mixed with other XPS oil so you are fine there but yes change the oil filter and replace them small 3/32" oil injection lines.

Yes, you must replace the needle and seat.
Genuine Mikuni...
Amazon.com: Mikuni 14-1077 Needle Valve 2.0 : Automotive

Yes, return the carbon seal. You should be able to just add a couple pumps of grease to your carrier bearing, don't go crazy or you will pop the seals.

1/4" ID Standard automotive fuel hose 25' is plenty.

Thank you.
I see you suggested ‎786-35015-2.0 . I was suggested to purchase 786-15005-2.0 by a mikuni dealer but they were unsure. How can I be 100% on the mikuni part number? It seems like they are almost all sold out in Canada and are months away...

Thank you.