My MC 54 250B, 2008 model just does not run much at all. By bobf (Read 3,858 times)

[bobf]

Alleyoop, in the post just ahead of yours I said I had just put the gas in there and it was not very old either. I bought it on Jan 24 2016 so not old. Today I bought some more for the scoot.

[Alleyoop]

Have you disconnected the tank vent hose from the little black box and leave it just hang and vent?
and the "Y" connector all it has is the hose from the SAUCER(ACV VALVE) and the hose going to the FUEL PUMP?

That would duplicates the time when you took the hose off the SAUCER(ACV) and left it unplugged and it ran good AND when you covered the HOSE from the ACV valve the motor died.

So it should run just like that time IF you have it connected like I have suggested.
Alleyoop

[bobf]

Alleyoop. When it ran good the vent tubing went to the fuel pump and the rubber carb mount and the ACV was left unconnected. When I tried to connect to the ACV, or put my finger over the end of the tub, was when the engine would quit.

Today the vent from the tank is hanging, no longer connected to anything or the charcoal canister. The other vent hose has also been disconnected from the charcoal canister and is free from the connections to the other vent tubes. It is just hanging around with nothing to do. It is currently just the way you sent it to me to be done.

Each time I try to start the engine with the ACV disconnected it will run for a few seconds at most then die. Then I can not get it to restart and have to wait till the battery is charged again. I just went through that a few minutes back. Not sure if it will start with the ACV is connected. Will try that tomorrow.

Somehow wonder about the electrical system as this is a new battery but only gets a few turns on the starter to kill off the battery. That is why I went and changed in my older battery for this newer one.

I spoke wrong in one of my earlier posts as I said I need to go to the doctor tomorrow. My wife proved me wrong and showed I was reading the calendar wrong. So tomorrow I will have some time to try the starting again.

Have a good night.

[Alleyoop]

If you leave the ACV tubing disconnected it is causing a very bad VACUUM LEAK you cannot have VACUUM leaks,CONNECT the hose to the ACV VALVE. ANY VACUUM LEAKS THE MOTOR WILL NOT RUN OR RUN VERY POORLY.

This is all a closed system the only air it should get is from the AIR FILTER BOX through the CARB, any extra air will cause starting and running problems.
Alleyoop

[bobf]

From your last post you are saying i must have the air tube installed or nothing. It ran a couple days ago and ran fine without the air tube. So today, when I get to time, I will install the air tube and try again to get it to start and run.

Still wondering where all that yellow liquid came from and how did it get to fill all those vacuum tubes. Some in the tube to the Carb, some in the tube to the fuel pump, some in the tube to to the charcoal canister, but still no source found. Amazing situation. A few days back I changed the fuel pump and no yellow liquid then.

Will put the air tube on and report events after that.

No comments on the battery being good for just a couple turns of the starter before needing recharge. Seems like a complete drain in seconds and no reserve for a second start without more charging done.

Will need to pay bills and do other domestic things first. Then back to the scoot.

[Alleyoop]

LIke this and also disconnect the VENT from little black box.

[bobf]

I am not doing too well today Alleyoop. When the engine was running it was slow and made lots of black smoke. I found the fuel pump was allowing, or I caused, fuel to be in the vac line. It looked clear and had no obvious odor so I took a small sample in a pie pan out to the driveway and lit my lighter. Big blaze for a moment. When the engine did run it put out black smoke and made backfiring noises and would not idle. I played with the valve settings but nothing changed until it would not run at all. That is when I was chasing the vac lines again and found liquid in them again.

So I took that fuel pump out and put the one I swapped out a couple days back in its place. So far the engine try's to start but has not yet. If this one fails I will put the other one in for a quick test and if it fails again, I will need to buy another fuel pump.

And for the vac lines I had it just like you wanted for a couple days now, including reversing the one you called a 'Y'. It seems like you have not read my words or I am not speaking properly. I will not be working on the vac tubes any more until I get this fuel pump thing straightened outs. If I need another fuel pump I will try to find a different vendor as this 'New pump' may also be bad. That is why I will run this one today, if it will, and then try the other one also. To make sure if it is good or bad or my mistake in setting it up.

I sure would not think it would work at all if I had not put the 'fuel in' and 'fuel out' and 'vac' tubes in the right places.

Tomorrow the wife wants to spend shopping and I have a doctor in the afternoon. So not much progress till Friday or Saturday.

Back to the scoot shortly.

Have a good day.

[Alleyoop]

To check if the fuel pumps are working disconnect the FUEL HOSE from the Carb and stick it in a nice clean container. Then just crank the motor over as if trying to start it, FUEL SHOULD stream out into the container if it does it is working. Then you can re-conntact the fuel hose back on the carb and pour the gas in the container back into the tank.

Try this take the hose off the ACV VALVE and plug the VAC HOSE UP which would mean only the fuel pump is getting vacuum and see if that makes a difference. I want to see if the ACV valve is causing the extra fuel constantly causing the black smoke. BUT MAKE SURE YOU PLUG UP THE VAC HOSE OFF THE ACV VALVE IF you have a GOLF TEE that works great.
Alleyoop

[bobf]

I can do as you suggest but that would not explain why I had gas in my vac line and that was my concern.

No more scoot till later this week as I said above.

[Alleyoop]

Normally if gas is in the VAC line means the FUEL PUMP is bad ALLOWING fuel to flow through the VACUUM LINE and that would cause to much fuel being fed to the motor. You can get something to create suction and stick it in the VAC hose going to the FUEL PUMP lIKE A BASTER and if the Fuel Pump is allowing fuel to flow through it GAS will be in the BASTER.
Alleyoop

[bobf]

Hello Alleyoop. I am again looking to buy another fuel pump. My original one won't work so I bought another one at about $40. And it appears to be the one to pump gas out of the vacuum line.

I have been looking on the forums for another one but would rather pay in the $20 or less range. Most do not show dimensions or bolt hole locations. Most seem to be at about 3.00 inches but my scoot requires 3.375 inches.

Do you know of any dealers that sell in reasonable prices with mounting hole dimensions of their products on display?

Been shopping and now ready to go to he doctors.

[Alleyoop]

Here is one for a little over $20 bucks. They do not have to be the exact size as what it came with. Don't forget that scoot was made back in 2007 sold as a 2008 parts parts change every year. As long as you have one mounting flange that is all you need. Most come with two but not needed.
Alleyoop
This says mounting holes center to center 87mm.
www.monsterscooterparts.com/fuel-pump-250cc-scooters.html

[bobf]

Thanks for the info and I think I will follow your suggestion and just order one of those smaller $16 dollar ones. Less loss if they don't work either.

The one you posted for me is the same as the one I bought and it does not work at all. So I will try to prime it to see if that is the problem and if not, then it goes to trash also.

Still being rushed for time as I now have to get some plantings ready for spring. I did not think owning a scoot would become a life long 'fix it' situation. Since coming out of the crate is has been take off the covers and fix this or that. My first fix was a problem with the gas tank as it did not hold the gas as the gauge port was leaking. Wonderful first experience with your new scooter.

[Alleyoop]

Where is your GAS TANK? On the Floor in FRONT or up high back of the seat? Reason I ask is IF the GAS TANK IS LOWER than your carb you need a FUEL PUMP, IF the GAS TANK IS HIGHER than your CARB you need a PETCOCK(Gravity feed system).

So just verifying what you need a FUEL PUMP or PETCOCK.
Alleyoop

[bobf]

It is on my floor ahead of the feet. I need a fuel pump and have already ordered one for $19.99. It should be here by next Friday.

Was working on the scoot a bit ago and it would not start. Running it would not bring gas out of the tube from the tank. It is just too slow as I pointed out a couple times even with a new battery. So I put on my primer cup and started that way. Now it was able to flow gas out the tube from the pump. So I switched to the pump to carb setup and it started and ran well. It ran till the radiator got hot and the fan came on. But it also started running slower and rougher. When it stopped I pulled the Vac line from the ACV and it had gas in it. So I pulled the vac line from the fuel pump and a lot of gas poured out of it.

Good thing that I already had order another pump. I ran a bit without the vac line attached and it ran well but no gas was coming from the vac line hookup on the fuel pump. So it must be the vacuum that somehow pulls the gas out and up to the carb.

Will find out next week end if a new pump fixes the problem.

The new pump I already had did not fix a thing which may be why I have been posting for so many months and getting no answers. Bad pump seems to be the problem and if another pump does not fix the problem that will be three in a row or I am chasing the wrong thing. No gas should be coming from the vacuum port on the pump.