1995 Seadoo SPX Carburetor needle/seat question

[eavega]

Hello all
So, I found me a project for the winter. I picked up a 1995 Seadoo SPX that had been "Redneck Engineered" some, and was no longer working. The PO decided that the mechanical fuel pump was not working, so he bypassed it and installed an electric fuel pump instead. He subsequently removed the electric fuel pump because he needed it for something else, and pretty much let the ski sit for a couple of years in his workshop.
I checked compression (about 145 and even on both cylinders) and good spark, so I figured I'd dive into the carbs and fuel system first. This is where my problem is. I'm not used to this Mikuni carburetor that has pressure springs and pop-off values on the needle valves (as opposed to floats which is what my outboards, IO, and motorcycles have all had in the carburetors). Anyway, when I tore down the carbs, I found the N/S that are in there are 1.5 mm. The parts catalog indicates it should be a 1.2 mm N/S, and I have found an online reference that indicates it should be a 2.0 N/S. I purchased the carb rebuild kits online, and upon consulting with the online store I was told to order the 2.0 N/S. Now on another PWC specific forum, I am being told that the 2.0 N/S are too big, not right, etc. Does anyone have a recommendation for me as to which one is right? I have no history of how the ski ran with the 1.5's, the parts catalog shows the 1.2, and the store says 2.0. Again, on the online forum, I was told that the 2.0 is used on that carburetor, but only in single carb applications. When you go to twin carb configurations it should be smaller. Any advice would be greatly appreciated.

Rgds

Eric Vega

 

[WCTori]

Eric, use the KISS approach. These are simple machines. Clean the carbs, make sure you find and clean the internal fuel filter that each carb has, and reassemble. Next, replace all the grey fuel line in the boat with new fuel line. These machines have a big problem with the factory grey fuel line disintegrating and clogging the fuel filters which makes the rear carb/cyl. run lean and burn up. Do these simple steps, and give it a try. If it was running well enough before and didn't foul plugs, or burn a piston then i'd start there and see what happens.

 

[eavega]

Thanks for the reply. In the end, I went back to the retailer that sold me the carb kits with the needles, and we both agreed that what was in there when the ski came from the factory was the 1.2 mm needle seats. I pretty much munged up the 1.5 mm needles that were in there trying to get them out, so when I rebuilt the carbs I used the 1.2 mm needles. I still haven't started the motor, but as of now I have rebuilt the carburetors (they were an unholy mess; I had to soak them, boil them, spray them down with carb cleaner, and blow them all out before I was satisfied that I had gotten them clean) and synchronized them, replaced all of the gray tempo line with new ethanol resistant fuel line (This included much more than what I pulled out of the ski, as the PO had bypassed both the venting lines completely, removed the ON/RES lines and left only the RES line, bypassed the fuel selector AND the water separating filter. Basically they had run a fuel line from the tank RES port through an inline filter, to the fuel pump, straight out to the carb fuel inlet, and the return line back to the tank.) I also elected to remove the oil pump and run premix. I may change that one at a later date, but I'd rather get the ski running with as few moving parts as I can get away with until I am sure that it is sound. As it is, I am debating on whether or not to tackle the VTS system. Apparently the PO removed the VTS motor, assuming it was busted since there are signs of oxidation around the remaining components. They did leave the worm gear and control cable, but attached an automotive window crank to the externals so you could adjust the trim manually. The aesthetics of it keep me from leaving the window crank there, and a new VTS assembly is less than $100, so I may still do it before spring, but I'll want to see if the ski runs before spending another $100 on a "nice to have".

Rgds

Eric