New to me Kawi 750 sx

Just purchased a 1994 750 sx

New to the site and to stand ups. Engineer and mechanic but clueless on these small two strokes. I just bought this ski from a good buddy who had just bought it from some one a few months back who had also just purchased it. Some where along the way some one spent some money. Long story short I don't know what mods have been done to this thing. I'm trying to figure out exactly what I have and what I need to do. It has a new engine and I don't think it was really ridden much after it was all put together. Hour meter said 15 hours when I got it. I was told it had stock carb all stock internals but it has a Mikuni carb. I had to have some work done to my Coffman manifold with the help of the guys on this site. Below are the mods I know it has.

Coffman manifold with coffman speed pipe ( I think is what its called).
Looks like an aftermarket intake manifold, with an adapter, and mikuni carb.
It has an intake grate and extended ride plate.
Rear sponsons and im not sure what all is done in that regard.
Blowsion handle bars and pipes and everything.
I just ordered a tdr water box that gets here today. It still had stock water box. It already has the water box bypass set up.

The ski seems to run perfect. On a hot start after it was shut off, like if I was riding it hard then shut it off and let it sit for a min or two and restart it. It will stumble for 2 or 3 seconds in the mid range as your first take off but then it clears right up and takes off and you cant make it do it again unless you shut it off. Seems like it will idle for days with no prob. I have to get through a big no wake zone whenever I take it out. So im not really trying to change the setup much or reinvent the wheel I just want to make sure I at least have a correct set up and am not leaving a bunch of power on the table some where.

I should have it running again tomorrow at which time I will adjust the low and high end of the carb and see where they are set. I plan on pulling the carb apart after I ride this weekend to see what jets are in it. I'm apprehensive to do this because it runs so good but I'm being told I need to make sure the jets match the pipe and water box and what not. To check which carb model it is I just need to measure the diameter of the throat right? For the record the water I ride on is 815' above sea level.

I checked compression and had about 165 front and back on a cold engine so I guess that means I prob have stock compression?

How do I check if I have timing mods. I have a nice digital light but again am unfamiliar with these little things. I assume you can pull one of these little plugs to view the flywheel? What is factory base timing? Or is there a way to tell visually if someone has done one of these timing advance kits I see on here. If it had some kind of MSD enhancer or timing box that would be visible in the E box right?

How can I check what impeller and jet I have? They look aftermarket to me. Are specs stamped on the blades anywhere usually that I could see with a scope or something?

I am exited to hear yalls opinions but assuming its jetted correctly, I plan on adding a timing mod if I don't already have one, ensuring I have a good low end performance jet/impeller, a good light weight flywheel, and leave it at that.

is there anything else yall recommend I so right off the bat?


Thanks for your help.
You will need to pull the front cover to see if it has a timing advance plate. They are typically 6 degrees which is too much for pump gas. I drill and tap new holes in the cover for 3 degrees advance.. The E-box needs to be opened to tell what CDI is in it. Stock 750sx is marked 3733, the best CDIs are from the 750SXI, they are marked 3738. Do a compression test, it needs to be under 180 psi. Your intake and carb is stock. If you run it as is, make sure to open the top mixture adjustment on the carb until the engine loses power. Then close it slowly until most of it comes back. This will prevent your pistons from melting if something else isn't right. It looks like your ski is in good shape overall and a good candidate for restoration. If you want to stay in the hobby for more than a few rides then an overhaul/restoration is required. There are few things in this world that get more abuse and neglect than a jetski. It looks like it has a lawnmower battery, that tell you everything you need to know about the previous owner!
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