Modern Vespa

In order to replace the fuel pump is it necessary to remove the fuel tank from the bike? If it is necessary I can only assume it drops out from the bottom? It looks like it is held in place by two bolts, one in front and one in the rear. Can I just remove the one in front and just pivot the tank down for the pump replacement or is it just easier to remove the tank. I'm sure at this point I've bitten off more than I can chew but it all only takes time. Thank God I'm on vacation for the next 3 days. P.S. The service manual is very vague to say the least.
Thanks Tom

It's been awhile since I've owned a 250 but I think I remember OAD dropped one on a 250 he was prepping for the someone's Cannonball run. If I remember correctly he was able to drop the tank to get to the pump.

Here's how the shop manual says to do it. I also am including the schematic.

Thanks Stickyfrog that was a big help. I got the tank out and also the pump. That pump was the worst I've ever seen. Ethanol gas sure did a number on the pump, the bracket and the filter. I got all the replacement parts for about $90.00. The pump now works but the bike still won't run. My next step is to replace the the injector. Oh by the way the removal of that gas tank was a pain in the butt. Now I get to put the whole thing back together. I sure do hope I can find a place for all those black screws.

Well done. I felt your pain at removing the tank and strewing plastics plus various sized screws around. I sourced my replacement pump from Quantum Fuel Systems, Ventura Ca. At $40.00. It is a quality item.
At least the injector is a 10 minute breeze.
My MP3 feels like it has had a long awaited birthday present.

I replaced the injector, easy job. Now at least it will start but won't run for more than 20 to 30 seconds. With a little help from some starter fluid I was able to get it to rev to at least 3000 rpm so it doesn't seem to be stuck at that dreaded 2000 rpm limit. I still have all the tupperware off just in case I need to get back in there. Keep in mind this thing sat for maybe 5 years or more. Is my next step the throttle body? I read somewhere on here they can be cleaned but need some kind of synchronization for it to work correctly afterwords. My local Piaggio/Vespa dealer isn't real keen on these Italian scoots so I'd just as soon send it somewhere that cares about these MP3's. Any ideas will be greatly appreciated.

Good on you getting it going
So continuing with the 'kiss' principle... had you checked the fuel delivery/pressure prior to fitting the new injector ? Robot shows how to do this on his excellent Vespa vids. Because the running only for 20-30 secs still sounds like fuel supply.
Also check that the air-filter isn't clogged.
The starting would also be helped with a fresh new spark plug... 'kiss' again.
A valve clearance check is also good for peace of mind.

Bonne chance

Thanks spdtwn, I was thinking last night that I should change the spark plug just for grins. Can't hurt. I don't even have the air filter on because I've been shooting starter fluid in there. I do know these things won't run right without that filter but I thought just for starting it should be fine. Am I wrong? I'll check out that vid you suggested. Thanks

Yes, it should run ok without the filter. Silly question-you do have the front suspension unlocked ?

spdtwn, Why is that a silly question? It won't run if suspension is locked? I'm sure I've tried it both ways. I did replace plug and maybe it runs/starts a little bit better. At least that is out of the way. My next step is the throttle body. Hope I can find a youtube on removal and cleaning. I saw a picture of the screw I'm not suppose to touch. I need luck and prayers.

Bike will start with suspension locked, but only run- reluctantly-up to around 2k revs- unless you are seated on the saddle-Piaggio safety feature. When on the center stand and unlocked bike will start and run up the revs normally. Seated or not. There are lots of postings on problems with the underseat pressure 'switching' and wiring to same. Did you check the fuel flow?

I will try it off the stand and like I said the front suspension is unlocked. The little button in the very front of where the seat would be is stuck in the down position. I can only assume that is the lock out for the seat. With the fuel line disconnected from the injector it pumps fuel for just a couple of seconds until it shuts off. I suspect this is because it knows when to pump fuel and or knows from the needed pressure. I'll check out your other suggestions later on today and reach out again. I sure don't want to take off that throttle body. Can you tell?

The switch is for the trunk light

the seat sensor is inside the seat and there is NO switch for it. the plunger switch you see at the hinge area of the seat when up is for the under seat light ONLY.

So if the seat sensor is in the seat do I just need the seat in it's normal position for the sensor to work properly? I did just try it with the stand up and the suspension in the unlocked position but no change in running. As I say very hard to start but it will start and run for 10 to 20 seconds with no throttle. I would say it could be cold but today in North Florida it's 82 degrees outside. We had to turn on the A/C for Gods sake.

The sensor works based on weight on the driver portion of saddle.

IIRC, the minimum required weight is 50kg (110lbs)

Bike on center stand, fresh fuel, ignition on, suspension unlocked, press starter. That's the starting sequence. Seated or not.