scooter 50cc vacuum problem By streetglide (Read 527 times)

[streetglide]

Why does the motor die,when vacuum,from fuel tank valve is connected to intake manifold port? Runs great with port open,but if you block it with finger it will start to die. ( when it should run better) Thanks

[Deleted]

that makes me think its too rich. the port being open lets more air in and leans it out.

[cyborg]

yes i agree check the air filter,it may be plugged up,,,also i would be going thru the carb the float needle may not be seating correctly and it's pouring fuel in or the needle tip may be worn and its not seating

[Bashan]

Yes, but why does his tank valve remain open without vacuum on it? He said it runs with the vac line off of the valve.

[streetglide]

Thanks for the ideas. It will run with vac line off ,until it drains carb bowl

[Alleyoop]

What appears to be hapapening is that when the vacuum is connected fuel is being sucked out through the vacuum hose and there fore flooding it with to much fuel. The Petcock is bad.
Alleyoop

[cyborg]

Alley is a genius again!!! Dammit,,, lol

[streetglide]

Why when I block off vac port(at intake) with finger it dies, it should run better,that's the same when I hook hose to it. No gas in hose. Valve works fine.

[streetglide]

Sept 2, 2014 20:01:57 GMT -6 streetglide said:

Why when I block off vac port(at intake) with finger it dies, it should run better,that's the same when I hook hose to it. No gas in vac hose. Valve works fine (opens &close)

[streetglide]

Sept 2, 2014 20:05:08 GMT -6 streetglide said:

Sept 2, 2014 20:01:57 GMT -6 streetglide said:

Why when I block off vac port(at intake) with finger it dies, it should run better,that's the same when I hook hose to it. No gas in vac hose. Valve works fine (opens &close) also when you turn engine over air blows out vac port at intake then it will start vacuuming??? Valve problem?

[Alleyoop]

HERE IS YOUR ORIGINIAL QUESTION:

Why does the motor die,when vacuum,from fuel tank valve is connected to intake manifold port? Runs great with port open,but if you block it with finger it will start to die. ( when it should run better) Thanks

So my question to you is Why are you just now connecting that up and having the problem?
WHAT did you do and or change to even have this disconnected in the first place? Leaving out important what you did just makes everyone guess.

Need to know what you did and or change and or added and or took off so the cause can be corrected.
Alleyoop

[streetglide]

Would not run unless you applied manual vacuum to fuel valve so it could get gas. Then when you get it running & hook vac back to vac port it would die. Fuel valve works fine.

[streetglide]

What I'm saying is why does motor Run with a vacuum leak?

[jct842]

I think we need to start at the beginning. When the scooter was new it must have run. Some where along the line it quit running. What we want to know is what happened in between. Did some one change jets? How did it go from running to this problem?

[streetglide]

It was runing fine then went to start,wouldn't run ,checked for gas,none,pull vac line off and used hand vacume to open valve ,thus allowing gas to Flo to carb