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Post by albongo on Aug 12, 2015 16:35:08 GMT -5
OK my scoot will lose power and die while riding.
It happened 3 times during a 15 mile ride and a couple of times on previous rides.
It feels like it runs out of fuel bit with out the cough. It just loses power and dies once the scoot had slowed. The last time it happened I opened the carb drain screw and fuel came out. Later I realised the carb fuel drain screw is at the bottom of the hose so the fuel that came out might just have been what was in the hose.
When the scoot dies I can start it again but it takes quite a few tries on the electric start, like it takes a while for the fuel to get to the engine.
I cannot explain a set of circumstances when it happens. So far uphill, downhill and various throttle positions.
I forgot my camera so I have no video but I'll try and get some when I can.
Anybody experienced something like this before?
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Post by 90GTVert on Aug 12, 2015 17:59:40 GMT -5
Try with the fuel cap off or loose (just make sure you don't lose it or don't splash fuel out). If it doesn't die, you've got a venting issue. I think you already said you tried a valve adjustment to no avail in another thread?
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Post by Fox on Aug 12, 2015 18:06:34 GMT -5
Sound like a fuel issue but maybe not. Your fuel tank is under the foot panel so it has a little vacuum actuated pump to lift the fuel up to the carb. Pull the fuel line off the carb for a second with the engine running to see how strong the fuel pump is pumping. Could be a crack in the vacuum line to the pump which would reduce the output of the pump.
Other suspects that come to mind:
Clogged fuel filter
Residue in the pump
Water in the gas tank
Fuel pump going bad
Vacuum leak somewhere on the scooter
Clogged vent on tank
Could be electrical
Loose connection at coil
Bad plug cap
Bad plug wire
Loose wire at CDI plug
Key switch
Kill switch
Intermittent spark from coil or pickup coil
Could be mechanical
Tight valve(s)
Low compression (rings)
Cam bearings sloppy
Loose head
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Post by albongo on Aug 13, 2015 4:21:10 GMT -5
90GTVert is there a way to take apart the fuel cap to make sure it's clearfrom blockages? Fox my fuel tank is under my seat above the engine. I have checked all electrical connections for security. I have adjusted my valves but it still happens. Would eliminating the vacuum petcock in favour of a fuel on off switch help?
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Post by kagetenshi on Aug 13, 2015 8:05:00 GMT -5
Putting an on/off switch solved the problem I had with my taotao dying on me. Might or might not solve your problem.
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Post by 90GTVert on Aug 13, 2015 8:10:34 GMT -5
When the tank is below the carb you can't swap out the petcock for a manual shutoff because you have a fuel pump. It's needed to move fuel uphill. You can only use a simple petcock or shutoff if your tank is higher than the carb so it can be gravity fed.
Sometimes there's a pinhole in the filler neck. Otherwise look for a small passage or hole in the cap.
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Post by Fox on Aug 13, 2015 10:55:39 GMT -5
Fox my fuel tank is under my seat above the engine. I have checked all electrical connections for security. Apparently he's got a 50cc version of that model with the tank above the carb so it has a regular petcock/gravity fed carb so I was wrong when I assumed it was a pump fed carb. The 150's have the pump system. Is your automatic petcock mounted to the tank or the frame? |
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Post by albongo on Aug 14, 2015 4:58:20 GMT -5
Fox my fuel tank is under my seat above the engine. I have checked all electrical connections for security. Apparently he's got a 50cc version of that model with the tank above the carb so it has a regular petcock/gravity fed carb so I was wrong when I assumed it was a pump fed carb. The 150's have the pump system. Is your automatic petcock mounted to the tank or the frame? Yes it's a 50cc version. The petcock is mounted to the frame. I tried to get a video of it dying last night but the damn scoot just kept going and refused to die!  |
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Post by katastroff on Aug 14, 2015 6:33:09 GMT -5
Just keep filming then.  |
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Post by albongo on Aug 17, 2015 16:26:42 GMT -5
Finally managed to get some video of the scoot dying. It died while going up a hill.
I managed to get it started again about 3:25
It died again a while later this time on the flat.
Any thoughts?
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Post by 90GTVert on Aug 18, 2015 11:00:38 GMT -5
Reminds me of running out of fuel/running very lean with the throttle surging. Here's something to compare to : VID. I would try ditching that petcock for a manual shutoff or at least replacing the petcock. |
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Post by Fox on Aug 18, 2015 12:31:51 GMT -5
Yeah it's gotta be a fuel supply issue. A bad tank vent or that petcock isn't operating right. A vacuum leak can cause this. Small crack in a line reduces overall vacuum to the petcock.
The tank must breathe in air to replace the volume of fuel that flows out or you will get a vacuum buildup inside the tank slowing or even stopping the flow of fuel to the carb. That's why Brent suggested running with the gas cap loose to see if it cures the issue. A tiny hole can be drilled through the gas cap to allow air in.
I don't know how yours is set up, but on most high mounted fuel tanks there's a vac hose connected to a vent on top of the tank that runs to a charcoal canister. There's a check valve on that tube between the tank and the canister that have been known to fail causing a vacuum build up in the tank.
The fuel filter should be installed between the tank and the petcock to prevent debris from entering the petcock. If the fuel filter is between the petcock and the carb then you might have something partially blocking the petcock starving the carburetor of fuel.
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Post by albongo on Aug 28, 2015 15:05:01 GMT -5
OK I replaced the vacuum petcock with an on/offs switch and blocked the vacuum port.
Went for a small gentle ride to the shops and had no issues. I need to take it on a longer run but haven't got the time yet. Maybe Monday!
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Post by albongo on Sept 5, 2015 15:38:21 GMT -5
It's all gone wrong!
I took the scoot about 500m to get a hair cut and then I was going for a ride of about 30 miles.
I parked up outside the barbers and forgot to switch off the fuel for about 15 min. Once I rembered I did switch it off. I had a hair cut and then tried to start the scoot. Nothing! Turned over but didn't fire. I thought it might be flooded so I walked home pulled the spark plug and let it air.
Tried to start it the following day the same thing. Thinking it might have been because of the new fuel switch I reinstalled the vacuum petcock but it made no difference.
I have stripped the scoot and checked the valves and all wiring connections. The carb is getting fuel so I think it's a spark issue. Hopefully I can locate the fault tomorrow.
It has not been a good few days!
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Post by 90GTVert on Sept 5, 2015 19:03:44 GMT -5
Checking spark and compression should narrow it down a lot.
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