Mobike Stalling

Sounds like the fuel filter...

To add to SolarEagle's diagnosis, has anyone checked the pick-up tubes in the tank, should be two of them (at least this is what I have seen). Each tube should have a filter screen on them.

One tube/screen for the run circuit and one tube/screen a little lower in the tank for the reserve circuit. I know you said the tank was cleaned BUT did anyone actually inspect the pick-up tube/screens?

One other item, has anyone checked the fuel selector valve for dirt/debris or a slight air leak?

In any case the problem is obviously a fuel delivery problem.

Why didn't you take it, immediately, back to "(company dealer network)" and make them put it right????

Taken twice. But the unfortunate part is

a) My office time and their time match.

2) At the time of check, that tank is in the non-dangerous zone so I don't know whether the rectification is OK or not till the petrol level falls down.

The funny part is as I said it is in the last couple of liters where the problem starts.

Initially I too thought about choking and yes the signal is that of the fuel starvation. But then what made me negate it (may be wrongly) is the head of that extra couple of inches enough to push the fuel through the choke? (whether the filter or the valve?)

BTW- once the fuel pipe (the flexible rubber one) was replace in between (the petrol theif had cut and damage it )

Is there a possibility of the kerosene mixed fuel through which I might have run for some time damaged some seals in the engine?

Any way i will be able to give it for servicing after christmas only sine I would be off to somewhere much north of you and getting frozen (nearer to the ducky) - weather shows quite below freezing and still dropping. Difficult for tropical guys.

meanwhile I will note down the points including SMs (infact that looks interesting since I had a feeling something might be pcreating vortex and pulling in air) and after coming back note the rest and make a check list for the mechanic .

Got a bit emotionally attached- ten years - eleven now, never had a problem, even minor, till that service man touched it.

On some bikes there is some kind of gas line cut-off system operated by manifold vacum or electric solenoid. It's purpose is to avoid carb flooding with the slightest floater needle leak when bike is parked. Malfunction (sticking) of this system causes similar symptoms. This device may also be integrated with gas knob or carb. Check if this is your case. S.M.

Now that is interesting. i never knew there is one. It all looks nicely sealed off with a rubber gasket too. But again the question is and most interesting one - why at a certain level of the fuel?

BTW- latest update - morning twice stalled in a 4 km stretch and almost at the verge of third stall reached the parking space. First stall at 32 kms in reserve - capacity 120 kms in reserve and had been regularly achieved previously (had gone for refill after 100 kms + of reserve several times)

While evening - had a run of 1.5 km and then 4 km, both without stall. Then filled up 10 lts of petrol and of course then 7 kms + 4 kms smooth. Theory ( last two litres et al ) holds till now

That happened to me once, some kids stole my gas cap and the replacement didn't breathe correctly. Took me a while to figure out why the bike would start and run fine for a while but then lose power and stall, then if you waited a while it would start and run again. In my case the tank level didn't change this that much, if anything it ran longer with less fuel and switching to the reserve didn't help either. This also happened to me with a snowblower same symptoms. It doesn't quite sound like the OP is having quite the same issue, I would look more at a fuel filter. To be sure I would check to make sure the cap can breath, just losen the gas cap and let some air in when the engine begins to loses power and if the engine perks up you know what the problem is. If not keep searching, or bring it back to the place that did the work as others have said.

Were any of the fuel lines replaced?

Some time ago I replaced a fuel line on my old KZ. The bike ran fine until the engine heated up, then it stalled.

It turns out I had cut the new fuel line a little too long. It expanded [grew in length] when the engine was hot and pinched at the bend, cutting off the fuel supply. I shortened the hose just a little and the problem went away.

Your engine might have cooled just enough in the time you spent fiddling with your fuel shut-off to allow the fuel line to return to its "at rest" length.

You could also take a look at the petcock. On my bike the petcock had two "straws", a short one for reserve and a longer one. There might be a problem with the longer one?

The fuel line was cut (by the petrol thief) after the problem, not before. I will check for the filter (and may be also the stop cock, may be it is choked)

The problem with the service persons here is give them a guess and they would replace it (honestly,) but no questions asked and not checked either (provided of course the part is available else they would simply say that that is not the problem). In my previous to last service (for this same problem) they have replaced the spark plug (without my guess of course) assuming that to be the problem.

But the question what is racking my brain is why doess it run smooth (today too after yesterdays 10 lt top up) it ran like a butter for about 10 kms no lack of power, not even the sputters and I am sure it would run like this for next 600 kms (ie 10 lts x 60 kmpl) and then I would again stall.

Is that small head difference (must not be more that 8"-9") enough to make this difference? More than the problem (I can easily overcome by topping up after every 550 kms or so just before it stalls _{like we do in the store Re-order Level Inventory control} ) but the behaviour I find very interesting and I am not sure I would get the answer from th e service person) After this list he would do all the things in the list and then i wouldn't know what was the root cause. had I been the mechanic (which unfortunately I never tried in this part despite being an so called Engineer ) I would have tried it one by one. The engineering aspect is interesting that's why I went through several runs with lower fuel in each fill to see the behaviour recurrence.

Anyway i would take to serviceman post christmas and see what happens.

And as far as the top fuel tannk cap is there it is not possible to open it (the key of the tank and ignition is common so i have to shut off the engine to open the cap)

What is the bike make and model?

My guesses sight unseen:

Sometimes there is a screen inside the tank valve body that might need to be cleaned.

There are also seals in that valve that when perished can cause problems.

The next time it plays up on you, don't fiddle with the tank valve. Remove the hose to see if fuel is pouring out nicely first. Then fiddle and observe.

I think you are very brave to trust the same "mechanic" again.

Kawasaki 150CC - kick start, 2000 Model.

Oh no, not the same mechanic - three different service stations (after first bust-up I do not dare to go to the same person again). But the last one had at least been a bit better. So I may repeat him. Else i will go to the larger service station in the region. (These are the branch offices (service and sales) nearby and there are 3 of them within some 10 km radius.

A KR150, ZX150 or what?

A dealer may not be your best option. Unless the lead mechanic is an enthusiast of course.

Are there no race tuning shops in your area?

I heartily agree with Wal's suggestion...sometimes the fuel feed can be "nearly" blocked...enough to run the engine but when the fuel head gets down low enough, the blockage can starve the engine.

So, when you have a stall, pull off the fuel line at the carb and see how much fuel is actually coming. If it is just a dribble, open the tank top and see if the fuel flow increases. If so, your cap is the problem.

So, if the fuel flow is good when you first pull the line off, you know your tank isn't the culprit.

If you find the fuel to the carb is good, then the next step is to disassemble the carb and check the float needle--it might be the culprit that is partially blocked.

Don't ask how I know this!!

If it is truly a partially blocked fuel flow that is causing your heartburn, you might also notice just a little less power at while cruising at high speed, even with a full tank, because you are burning more fuel and the blockage will be limiting the full fuel flow.

Jon.

In addition to the other suggestions I think it likely that the kerosene has damaged/swelled some of the rubber parts in the carburettor or perhaps in the tankvalve, reducing the flow capacity. A carb overhaul would probably be a good thing anyway, make sure you blow all the channels out good and note the positions of all the needles when disassembling so you can return the correct settings. (You should try to do it yourself if you can, there is no better way to learn it.....

At first I thought of the vent in the gas cap on the tank, but the problem should then be worst when the tank is nearly full and it is the oposite.

Good luck with it.

Finn