Carburetor Adjustment???

[Vesterbye]

I'm finally finish with my rebuild But in one of the carburetors the High Screw Needle was broken, and I replaced it with a new one. But how do I manuel adjust my carburetors?? My 93 Polaris 750 is premixed, I've installed a three outlet fuel-pump, new gaskets and pistons, cleaned the carburetors and also new spark plugs, but I want to be sure before I start it up, that my carburetors are adjust correct, so I don't blow another piston.

[beerdart]

For the 93 750 I show Highs Mag 7/8 turn Center 1/2 turn PTO 5/8 turn Idle all 1/2 turn. I would go an extra 1/2 on all high screws to be safe and tune from there better rich than lean.

[Vesterbye]

Okay.. Should I screw it all in and then turn the Mag 7/8 out, or?? What about the Low screw needle??
Extra question, what kind of oil should I use to premixed, just 2-t??

[beerdart]

Idle(Low Screw) all 1/2 turn. Yes turn the needles in all the way do not force them then back them out the recommended amount.

[K447]

...what kind of oil should I use to premixed, just 2-t??

TC-W3 is the recommended 2-stroke oil.

There are a number of brands available, including Polaris, Yamaha. Sea-Doo oil 2-stroke is a little different, so stick with TC-W3 rated oils.

You can not use regular 4-stroke motor oil.

[Vesterbye]

Can I use 2-stroke racing oil from Shell????

[Vesterbye]

I'm using it for my gocart!

[xlint89]

For breaking in the rings, you should use nonsynthetic oil. It's too slippery to properly break them in.

So use regular tcw III "dinosaur" oil at 32:1 for break in and 40:1 for running normal.

[K447]

Can I use 2-stroke racing oil from Shell????

There was a recent discussion about 2-stroke oils, and the oil rating systems.

Short answer;
Use oil rated for TC-W3 (old Polaris minimum spec),
or ISO-EGD, or JASO FC (better oils, Polaris modern spec)

An interesting side note I came across was that the racing oriented 2-stroke oils are indeed designed to provide lubrication in extreme engine conditions, but they also assume that the engine will be frequently inspected internally and rebuilt.

The racing 2-stroke oils can have much higher deposits, since the engine will not be running hundreds of hours before being taken apart. This means some racing oils are a poor choice for a non-racing engine, as you will have excess oil residue accumulation inside the engine. If the engine has exhaust power valves, they will become sticky prematurely, and require more frequent cleaning.

Not all racing 2-stroke oils would have this problem, but you need to know what oil you are choosing, and what characteristics it has.