Modern Vespa

So I finally got my scooter running!!!

The only problem is I have no idea if the oil pump is working correctly and pumping oil into the carb. Is there any way that I can know that I am auctually getting oil into the engine?

Also, how can I know that the engine is pumping the right amount of oil into the carb?

Lastly, what happenes if there was no oil getting into the engine?

You can introduce an air bubble into the oil line where it plugs in at the carb. When the motor runs, you'll see the bubble slowly get drawn in. If not, you need to find out why it's not ASAP!! You might be able to see a bit of blue smoke in the exhaust if you're lucky.

As far metering the oil pump, you'll need to find a Zuma specific workshop manual and see how the oil pump is adjusted. On an ET2, there's a line on the pump that matches a line on the engine case. Find your oil pump and see if it has the same idea.

Lastly, if you don't add two stroke oil, you'll seize your piston and rings. Bad stuff!

The first thing until you are sure is to run pre-mix in the gas tank at about 50:1 ( or what is says on the container) this will avoid seizure.

There should be two cables from the twist grip or a split somewhere with the second one going to the oil pump (which will be under a plastic cover?). On the quadrant of the oil pump will be an arrow or line that lines up with a mark on the pump body either at 0 or 100 % open. There will be an adjuster for that cable. It will be obvious whether 0 or 100%

Example below.



When adjusted properly run the scoot for some kms and see if the oil tank level goes down or if there is too much smoke from the exhaust.

No level change or no surplus smoke you'll have to have a closer look at the pump and the tubing.

If you prefer you can disconnect the rubber tube from the engine inlet ( manifold) and run the engine and see if any oil comes out.

If still in trouble feel free to come back or PM.

Sorry i keep clicking quote not edit.

To test the oil pump, mix a half tank of premix 50/1 in the tank, 2 1/2 ounces of oil to 1 gallon of gas.
Pull the small oil line from the check valve on the carb. Start the bike. Count the number of drops per minute at the different rpm ranges, if your output is different from the chart below replace the oil pump or adjust the oil pump cable. Failure to run premix during this test will damage the top end of the motor.

50cc Scooter

Idle (1700 rpm) 3-4 drops

4000 rpms 5-9 drops

7000 rpms 8-12 drops

Not on a Zuma.

But there is a cable to be adjusted

Nope.
https://www.yamahasportsplaza.com/oemparts/a/yam/5003aedaf8700212fc83c0d0/oil-pump

Trick

I've never seen a Zuma autolube pump fail, and they also self purge after being unplugged from the carb. Now, if you removed the shroud from the cylinder make 100% sure the hoses are rounded correct
It's very easy to pinch a hose putting the shroud back on. And no adjustments needed.

And what was preventing the Zuma from running in the first place?

Awesome! Ill try to test that out, I dont have reasoning to say that the engine is not getting oil, I just know the disastrious results that can happen if the engine does not get any oil.

I was able to replace the carborator with a new one and after that, it started right up with no problems. I have not yet had the time to take apart the old stock carb to investigate what might have happened inside there.