1988 Elite SA50 carburetor

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Wheelman-111
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Re: 1988 Elite SA50 carburetor

Post by Wheelman-111 »

Greetings:

Your plan is sound, except that the "air screw" and fuel mixture screw are one and the same. The other screw is simply a throttle-stop. That one is set to lift the slide about 1.5mm from bottomed out to get the motor started.
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

Thanks again Wheelman,

The throttle stop screw still is part of the process when setting the idle though right? Air screw 1 3/8 out and throttle stop maybe one turn out from seated. Then adjust air screw 1/4 either way for highest idle then throttle stop adjusted either way till 1800 rpm?
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Re: 1988 Elite SA50 carburetor

Post by Wheelman-111 »

Greetings:

These things don't like an open throttle when starting cold on bystarter. One turn out from full seated might be too much. Instead, look at the slide as you screw the throttle stop in, and stop when the slide is up from bottom a mm or 2.
Wheelman-111
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

So I pulled off the air box, pulled out and correctly reseated both the throttle stop screw and the throttle valve. I looked into the carb and checked the grip throttle and everything with that is working great. But..... when I ride it down the road...... same sticking problem where it won’t throttle down right and I get the unwanted cruise control. I have it idling decent at 1800 rpm and not sure what else to try. The grip throttle pops back nicely too. Any chance it’s the bystarter? It starts right up but it is onl and has been taped up a few times by the previous owner. So close yet it’s still not safe to ride to work with that throttle issue. I’m not giving up though!
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vintagegarage
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Re: 1988 Elite SA50 carburetor

Post by vintagegarage »

When the engine is idling at 1800 RPM and you screw the air screw (gently) all the way in, does the engine stop? If it doesn't, then your idle circuit is blocked. Your symptoms sound like your scooter is idling on the main jet, and the idle circuit is still clogged up. With the idle jet clogged up, you can make the scooter idle fairly well by screwing in the throttle stop screw too far, but it won't reliably return to idle after a high speed run. If your engine stops when you screw in the air screw while it is idling, then your idle circuit is fine and you can ignore this post.
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

That’s a really good tip but it does shut down when I screw the air screw all the way in. Thanks for the suggestion though, I’m baffled and will try anything at this point.
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Re: 1988 Elite SA50 carburetor

Post by Meatball »

Have you inspected both crank seals? If unregulated air is entering the cylinder, the revvs will hang before it settles down. This inspection requires the removal of the variator on the belt side and the flywheel/stator assembly on the other....special flywheel removal tool required..about a $4 tool.
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

Meatball,

I have not inspected those and being the novice I am that sounds daunting. It may very well be the problem but I think I would need a true mechanic for that. Maybe it’s time to get it looked at as much as I don’t want to spend the money. I will search this forum to see if there is a step by step description of how to do this. I dont mind buying the tool if it’s straight forward to fix. Like the carburetor, it just sounds scary but I’m glad you convinced me to do it myself.
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Re: 1988 Elite SA50 carburetor

Post by Meatball »

What is your geographical location?
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

I’m in SW Florida. I think I might try buying a used throttle valve. Knowing I put it in backwards several times maybe I damaged it although from appearance it looks fine. Someone has a good used OEM throttle valve for a 1998 Elite SA50 on eBay but my sa50 is a 1988. Do you think that part is interchangeable even though the year is 10 years newer. This seller has a bystarter too for his 98 elite and if that part is interchangeable I would buy both. Thoughts? Thanks Meatball!
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