Seadoo wont run after carb rebuild.

[Scrappy996]

Hi Guys, its been a while since ive posted, and I would like to say how much this forum has helped me out with my seadoo!
Thanks

Seadoo 1998 Gti 717cc Rotax 85hp
Compression : 139 : 137
Cylinder Bored: .75 / .25
Spark Plug Gap : .022
Premixed, Oil Injected Block Kit.
Rebuilt: 30hour on before failed carb build
New Lines (No Gray)

I rebuilt the seadoo after an oil pump failure blew the piston rings. The seadoo ran great after the rebuild, and in fact put about 20-30hours on it! I rebuilt the carb because I hadnt done it before and now it wont run !! Dammit!

- The lines in/out for fuel and air are correct.
- Yes the pulse line is on
- The tank pressurizes (also gas cap closed)
- Pop off 26psi
- LS 2.5 (original setting)
- High 0
- Idle 2

-Engine starts / runs with pressing throddle or holding throddle little open!
-Engine doesnt start with pulling choke.

Im running out of self modivation with this seadoo and I am completley stumped! If anyone has suggestions please let me know!

Ive come down to trying,
- rebuild carb kit (defective kit)
- clean tank + filter (even tho done before)
- adjusting pop to 35psi and LS to 1.25

I saw gas/oil coming out with water onto driveway unless I spilt gas on my gravel driveway before, maybe a crank seal or something?

 

[mwat65]

Sounds like it’s flooding

 

[mwat65]

That single carb setup has given me problems in the past. Last time I finally gave up and bought a new carb. If you value your time as I do sometimes it’s the way to go. Just an option.

 

[mikidymac]

First you shouldn’t have two different bore sizes but that’s not your issue.

If it’s dumping oil and fuel in the driveway your needle and seats are leaking.

 

[Scrappy996]

Okay so if its flooding ill replace the needle and seats and order a new carb kit.

I agree with trying to keep the same piston sizes, a mechanic told me that its so small it wont make a differance?

Now why wont it run after its cleared the extra gas in the carb, the only other thing is the rave valve and head behind carb might be scrated? Could that cause it?

 

[mwat65]

You don’t have rave valves on a 98 gti. Did u mean rotary valve ?

 

[Scrappy996]

Yes sorry rotary valve, and I finally got it running just now. The pop off was set to 25psi and I put it up to 35psi, also the spring was not strong enough causing the flooding which you said above. Thankyou everyone for your time and replys! Cheers

 

[mikidymac]

How did you increase the pop off? You should only be using the oem spring weight.

 

[Scrappy996]

Yes, I put back the old spring that was in the machine. The new spring provided in the kit I ordered was wayy off.

Also, I believe the diaphram assembly was alittle smaller in the kit and that might have caused the valve to stay open inside carb.

I learned my lesson and purchased from SBT like I should have done at the start.

 

[mikidymac]

First never use the spring from the kits.

Second do not use a carb kit or carb parts from SBT. WSM or Wonderosa as they are not Genuine Mikuni parts and will cause problems. Mainly the rubber parts and diaphragm are too rigid.

 

[Scrappy996]

Where would you suggest then to order a rebuild kit from? I was just about to order from SBT but will hold off then!

 

[ah64driver2002]

Osd parts has genuine rebuild kits

 

[mikidymac]

I get them from amazon and ebay too. Just make sure they came in the sealed Mikuni packages. My carb rebuild thread below lists the part numbers.

 

[Scrappy996]

Okay great Ill check them out tonight! Thankyou guys so much! And special thanks to Mikidymac

 

[Scrappy996]

Its also funny because the original kit was from amazon, maybe it was counterfeit. Ill watch out for the sealed bags next time !

 

[mikidymac]

The genuine kits come on a paper card with the parts loose in it not a bag.
One stoop shopping for everything and genuine parts is OSD seadoo.

 

[Scrappy996]

Perfect Ill make sure thats what I buy next time! Thanks

 

[Scrappy996]

So an update !

Got the seadoo out onto the water today, its running at about 1700 - 2000 at idle, but when given throttle fast it bogs, slowly throttle when it reaches 3000rmp it has great throttle responce and flies. Also when letting go of throttle it reaches 2200 then a few seconds drops to 1500 and back up to 1700 like it chokes or something. Weird !
It doesnt like choke and throttle or choke at all.

- checking needle and seat
- checking rectifier
- checking spark plug gap
Pop off is set at 35 and low speed 1.5 high speed 0. Waiting on CORRECT carb kit now to arrive.

 

[mikidymac]

I would wait for the correct carb kit before you run it again so you don't fry a piston. Also make sure you get good strong streams out of the 3 little holes in the lower carb body. See Post #4 in my carb rebuild thread.