SA50P problem
Moderator: Moderator
SA50P problem
I am trying to get an SA50P running after sitting for many years. Replaced carburetor by-starter, fuel guage sending unit, battery,fuel lines, etc. Cleaned carburetor. I didn't have an air filter yet but started it and ran it. It started and ran really well. Got air filter and installed it. Engine started and ran well up to nearly max rpm then bogged down. came back when I backed off throttle. Checked manual to adjust air screw.Discovered that air screw was screwed all the way in to the seat. I set it to 1-3/4 turns out and engine started fine but bogged as soon as I added throttle. As I screw the air screw in more, the rpm where the bog begins increases. Any ideas?
Re: SA50P problem
The air screw adjusts the early portion of throttle response. Sounds like something with the main jet or fuel delivery. Did you unscrew the main jet and clean the little holes in the jet needle behind the main jet?
Is it a bog that gurgles/stutters, or a bog that's clean but seems like it's fading away / getting weak and kinda higher pitch? First description is too rich, second description is too lean.
There could also be a clog somewhere in the fuel delivery, that's only showing itself at full throttle. This could be a clogged fuel filter, sketchy petcock, float etc.
Is it a bog that gurgles/stutters, or a bog that's clean but seems like it's fading away / getting weak and kinda higher pitch? First description is too rich, second description is too lean.
There could also be a clog somewhere in the fuel delivery, that's only showing itself at full throttle. This could be a clogged fuel filter, sketchy petcock, float etc.
Re: SA50P problem
I should add, are you the only owner? It would be good to know if someone had messed around with it in the past.
Re: SA50P problem
The bogg is clean and quits when I let off the gas. I'm convinced the carb is clean. Installed a new petcock. I suppose it could be the float but it runs so well without the air filter that I doubt it. It could be a clogged line but why would it run so well without the air filter? I am not the first owner. The first owner had it stored at the beach during a hurricane so there was a lot of water damage. He got it running but several parts were toast and he never got it running right. (Wrong throttle cable...only one cable...oil pump was wired full open when I got it. Smoked like crazy at low rpms.) I will check the fuel delivery system.
Re: SA50P problem
I assumed you already checked for air leaks? The below advise is moot if there's an air leak.
It sounds like it's running lean. What main jet is installed? Stock is #68. If he derestricted the exhaust and it's running well with airbox off, the jet needs to be bigger like a #78 to #84. Buy this jet kit and try a larger jet:
http://scooterswapshop.com/store/scoote ... ?limit=100
When you say air filter do you mean literally the foam filter inserted in airbox, or the entire airbox? The SA50P airbox restricts the air some. A common mod is to punch out an extra tab on the airboxes inlet along with opening up the exhaust inlet (see derestriction procedures). It's not a great idea to run it without a filter of some kind.
It sounds like it's running lean. What main jet is installed? Stock is #68. If he derestricted the exhaust and it's running well with airbox off, the jet needs to be bigger like a #78 to #84. Buy this jet kit and try a larger jet:
http://scooterswapshop.com/store/scoote ... ?limit=100
When you say air filter do you mean literally the foam filter inserted in airbox, or the entire airbox? The SA50P airbox restricts the air some. A common mod is to punch out an extra tab on the airboxes inlet along with opening up the exhaust inlet (see derestriction procedures). It's not a great idea to run it without a filter of some kind.
Re: SA50P problem
I don't think he changed the jet. I ran it with the air box on but no foam filter and it ran great. It was when I installed the foam filter that the bog began. Air leaks where? I have heard of increasing air by opening up the air box but mixed opinions about that. I'm all for increasing the performance but want to get it running right first so at least I am starting from "correct". It's such a sweet little scooter and I mainly want it for the wife because it is so simple and she is almost 60 and not a "rider".
- Wheelman-111
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Re: SA50P problem
Greetings:
It the bog began when the air flow restriction of the foam filter was added, then the jet is too rich. If you don't Think the jet was changed, then you're not sure. Remove the carb and check.
It the bog began when the air flow restriction of the foam filter was added, then the jet is too rich. If you don't Think the jet was changed, then you're not sure. Remove the carb and check.
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
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
Re: SA50P problem
If you feel the fuel system is good then a trans over haul would be the next thing to check, the net can't solve all problems.
some people dream of speed, i own your dreams!