Debra
01-04-2007, 11:31 AM
Dear Mr. Lee,
A friend of mine had just bought Zenoah G20ei. We have decided to have it bench tested.
We have used the following for our initial set-up :
15 x 10 2 blade propeller (plastic)
40:1 gasoline
SS 16 Sulivan Tank
Hydrimax 4.8V 1200 mAh
12V High Torque Starter
Upon re-checking all the necessary connections we started it up easily and ran very nice for 15 minutes. Then it quits on its own. My friend and I stared at each other and wondered what went wrong? We have noted though that the fuel thank was too low against manufacturer recommendation, so we raised the tank as recommended. Thereafter we could not even start it.
We replaced our Hydrimax 4.8V 1200 mAh battery with a newly charged one and upon re-starting it roars back into life but ran only for 5 minutes and the rpm decreased then it quits again as if it’s deprived of fuel. There’s absolute no reaction despite of revving up the throttle.
We even tried to manually primed it by choking the jet by our palm for it seem choking it with the built in lever the fuel do not flow in the carb. We’ve tried blowing on the intake fuel line and it seems plugged – or can’t blow it thru – is that normal?? Played around with different L & H setting no avail.
The manual by the way is very consise and we are at lost what is the original factory setting of L & H.
We don’t know if this is of any importance but, we mounted our Zenoah side ways, does it requires specific orientations?? This our first time in gas engine. We anticipate our thanks for your kind attention.
Glenn Bulmer & Jun C.
Philippines
Dear Mr. C.,
As this is your first gasoline engine the first thing that comes to mind is have you replaced the silicon fuel lines with neoprene or Tygon lines? Gasoline softens silicon and turns it gooey.
The fuel pick up line in your fuel tank could be closing down not allowing fuel to pass.
When the engine shuts off remove the sparkplug, lay it on top of the head, spin the engine with the starter and see if the plug is firing. Possibly the capacitive discharge unit is cutting out when it gets hot.
If everything checks out okay to this point then remove the cover plate on the side of the carburetor with the fuel inlet nipple and you will find a small cup shaped filter screen. Remove and clean this. This could well be the cause of your problem, so be sure to use an inline filter between the fuel tank and carburetor.
You can not blow through the fuel intake nipple as Walbro carburetors have a fuel shut off needlevalve that shuts off the fuel flow until the engine is turning over and venturi vacuum triggers the valve. This due to the Walbro carburetors having been intended for use on string trimmers, weed wackers, etc.
As for proper needle setting - isn't this mentioned in the operating instructions you mention? I don't have a Zenoah G20 to check but my G-38 and G-72 twin both do. Generally, 1 1/2 turns open on both the H (high) and L (low) needles with get the engine running on the rich side.
And incidentally, a 40:1 mix is okay after break-in but you should be using a 32:1 mix as recommended by the Zenoah factory during the break-in.
Let us know what you find.
Clarence Lee
Dear Mr. Lee,
Thank you very much for technical advice. We have noted all your instructions and our second try for running the Zenoah G20 turned out successfully.
You may want to know that even before our first try we installed Tygon lines already in our fuel tank. Moreover, following our intuition that we are employing a gasoline with low content octane during our first run, we replaced it with high content octane and mixed it 32:1.
We are very much pleased with how our Zenoah’s running. We again express our thanks for valuable advice.
Best regards,
Jun C. & Glenn B.
Philippines
A friend of mine had just bought Zenoah G20ei. We have decided to have it bench tested.
We have used the following for our initial set-up :
15 x 10 2 blade propeller (plastic)
40:1 gasoline
SS 16 Sulivan Tank
Hydrimax 4.8V 1200 mAh
12V High Torque Starter
Upon re-checking all the necessary connections we started it up easily and ran very nice for 15 minutes. Then it quits on its own. My friend and I stared at each other and wondered what went wrong? We have noted though that the fuel thank was too low against manufacturer recommendation, so we raised the tank as recommended. Thereafter we could not even start it.
We replaced our Hydrimax 4.8V 1200 mAh battery with a newly charged one and upon re-starting it roars back into life but ran only for 5 minutes and the rpm decreased then it quits again as if it’s deprived of fuel. There’s absolute no reaction despite of revving up the throttle.
We even tried to manually primed it by choking the jet by our palm for it seem choking it with the built in lever the fuel do not flow in the carb. We’ve tried blowing on the intake fuel line and it seems plugged – or can’t blow it thru – is that normal?? Played around with different L & H setting no avail.
The manual by the way is very consise and we are at lost what is the original factory setting of L & H.
We don’t know if this is of any importance but, we mounted our Zenoah side ways, does it requires specific orientations?? This our first time in gas engine. We anticipate our thanks for your kind attention.
Glenn Bulmer & Jun C.
Philippines
Dear Mr. C.,
As this is your first gasoline engine the first thing that comes to mind is have you replaced the silicon fuel lines with neoprene or Tygon lines? Gasoline softens silicon and turns it gooey.
The fuel pick up line in your fuel tank could be closing down not allowing fuel to pass.
When the engine shuts off remove the sparkplug, lay it on top of the head, spin the engine with the starter and see if the plug is firing. Possibly the capacitive discharge unit is cutting out when it gets hot.
If everything checks out okay to this point then remove the cover plate on the side of the carburetor with the fuel inlet nipple and you will find a small cup shaped filter screen. Remove and clean this. This could well be the cause of your problem, so be sure to use an inline filter between the fuel tank and carburetor.
You can not blow through the fuel intake nipple as Walbro carburetors have a fuel shut off needlevalve that shuts off the fuel flow until the engine is turning over and venturi vacuum triggers the valve. This due to the Walbro carburetors having been intended for use on string trimmers, weed wackers, etc.
As for proper needle setting - isn't this mentioned in the operating instructions you mention? I don't have a Zenoah G20 to check but my G-38 and G-72 twin both do. Generally, 1 1/2 turns open on both the H (high) and L (low) needles with get the engine running on the rich side.
And incidentally, a 40:1 mix is okay after break-in but you should be using a 32:1 mix as recommended by the Zenoah factory during the break-in.
Let us know what you find.
Clarence Lee
Dear Mr. Lee,
Thank you very much for technical advice. We have noted all your instructions and our second try for running the Zenoah G20 turned out successfully.
You may want to know that even before our first try we installed Tygon lines already in our fuel tank. Moreover, following our intuition that we are employing a gasoline with low content octane during our first run, we replaced it with high content octane and mixed it 32:1.
We are very much pleased with how our Zenoah’s running. We again express our thanks for valuable advice.
Best regards,
Jun C. & Glenn B.
Philippines