PX not starting - fuel issue
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Hooked
2006 px125
Joined: 28 May 2010
Posts: 331
Location: Perth, Scotland
Sat Feb 08, 2020 5:03 am quote
Had problems with my PX not starting, so got down to trying to trace the problem.

Started with fuel, and discovered that no fuel coming into carb.

Kink in fuel pipe, fuel tap, blocked fuel cap.

Blew through fuel cap and it seemed okay. Never had an issue with a fuel tap before, so lifted the tank out to have a look at the pipe. As soon as tank was a bit higher the fuel started to flow.

The only thing I could think of was length of fuel pipe (it was replaced during recent engine rebuild) and it dropping a bit lower than it was meant to below fuel tank?

Has anyone else had issues with fuel getting to carb that was down to length of fuel pipe?

I have shortened the length of the fuel pipe by about 8cm (put tank back in, pulled as much spare into carb as I could) and I am now getting flow into the carb.

Iím a bit worried that if length wasnít necessarily the problem could I be setting myself up for fuel starvation and a seize on my newly rebuilt Pinasco 235?

I would add that the fuel in the tank was quite low when I was having the problem.
Moderator
P200 PX150
Joined: 28 May 2008
Posts: 4048
Location: Hustletown, TX
Sat Feb 08, 2020 5:47 am quote
Common issue to have a fuel line too long resulting in poor fuel flow.
Sounds like you have sorted the issue. I wouldn't worry about the length of the fuel line or fuel starvation causing a seize. (no fuel = no combustion = no piston moving). If your autolube is working then your mix screw is the key to helping prevent a seize.

Search "plug chop" on the NSM forum.
Getting your mix dialed in on a kitted scoot is hella important.

PS - My advice is worth a cup of coffee on a good day. Ask yourself is today a good day?
Hooked
2007 Stella 150
Joined: 02 Nov 2019
Posts: 218
Location: Rochester, Minnesota
Hooked
2006 px125
Joined: 28 May 2010
Posts: 331
Location: Perth, Scotland
Sat Feb 08, 2020 10:08 am quote
Good shout.

I stopped using the standard transparent pipes a while ago. I had issues with the inner breaking down with ethanol and blocking jets. I use good quality black rubber motorbike pipe instead.
Ossessionato
Joined: 26 Oct 2015
Posts: 2079

Sat Feb 08, 2020 11:10 am quote
Iíve had good luck with that reinforced fuel line in my Lambretta. But I seem to recall trying to use that same 6mm hose on my Vespa fuel tap, and it was just too dang small of an ID to fit. I think 7 or 8mm is needed on the Vespa? I also bought a few of those SIP tank adapter brackets...and they are still on the shelf gathering dust. Once I eyeballed the angle of them, i didnít see them as beneficial. It would also create two more places where a fuel leak can happen. I ended up using that crappy clear OEM Piaggio fuel line that lasts for about a year. In my next SIP order Iím hoping to remember to order a larger ID of that reinforced fuel line.
Hooked
2007 Stella 150
Joined: 02 Nov 2019
Posts: 218
Location: Rochester, Minnesota
Sat Feb 08, 2020 3:55 pm quote
whodatschrome wrote:
Iíve had good luck with that reinforced fuel line in my Lambretta. But I seem to recall trying to use that same 6mm hose on my Vespa fuel tap, and it was just too dang small of an ID to fit. I think 7 or 8mm is needed on the Vespa? I also bought a few of those SIP tank adapter brackets...and they are still on the shelf gathering dust. Once I eyeballed the angle of them, i didnít see them as beneficial. It would also create two more places where a fuel leak can happen. I ended up using that crappy clear OEM Piaggio fuel line that lasts for about a year. In my next SIP order Iím hoping to remember to order a larger ID of that reinforced fuel line.
Wrong hose link, I bought the 8mm stuff, need to look closer next time.

https://www.sip-scootershop.com/en/products/fuel+hose+toyox+_40281300
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