I have an old Mantis Tiller and I bought a new carburetor last year and ran it for a short time. I took it out from vinter storage and it won't run at all. When I looked closer I discovered that it does not pump up petrol and fill the primer bowl. I took the carb apart and used compressed air on various places but it doesn't seem to have helped. Any ideas?
Mantis tiller
- Thread starter hcccs
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If the carb is not gravity fed, follow the fuel line back from the carb and you should see a black plastic device with 3 nipples. That is the fuel pump. You have a fuel inlet, fuel outlet, and a vacuum line going to the engine that works the pump. Inspect that for cracks and make sure the lines are on securely. It could have went bad. You can probably gravity feed the carb to see if it will run and then you know the problem is the fuel pump or possibly a clogged inline fuel filter.
Also sometimes the rubber on the float needle sticks and fuel wont run in the bowl. If you're not getting fuel in the bowl then it has to be from the float needle back to the tank somewhere.
Also sometimes the rubber on the float needle sticks and fuel wont run in the bowl. If you're not getting fuel in the bowl then it has to be from the float needle back to the tank somewhere.
With those simple suction style carbs you need to figure out if you are getting too much gas or too little Take a note of where the adjusting screws are set and adjust from there, but remember where you started, because fresh fuel will eventually clear the varnish inside.
one screw is the low speed/idle setting and the other is high speed jet
When you put the tiller away, you are supposed to empty the tank and let the engine run til dry.
one screw is the low speed/idle setting and the other is high speed jet
When you put the tiller away, you are supposed to empty the tank and let the engine run til dry.
Oh ok weedeater type carb. I just had a problem out of my tiller with that type of carb. I replaced the carb and then found out gas had soften the inlet line and the line was sucking together preventing fuel flow. I could actually see the line in the tank pinching but you may not be able to depending on how yours is made.
You check the filter?
Changed it out too.
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Yes it is the cardboard gaskets in the carb that fail and leak air not the polymer diaphrams. You need a carb kit. The impulse tube coming from the body or lower part of the case provides the negative and positive pressures for pumping so insure it is not collapsing. Two cycles are air pumps. You have an air leak...somewhere.
OK, it's been a while since I struggled with the Mantis. I took off the carb and also the fuel hose with filter from the tank. The filter is almost new and there is no obstruction there. I put the hose with filter into a can with fresh petrol and connected the carb and pressed the primer bowl. I can't get any petrol into the bowl but I get a lot of air bubbles in the can. I gave in and thought there was something wrong with the carb after all so I purchased still another one and I get the same result. How is it possible? I will not tell you in words what I think of the Mantis carbs which I have had problems with for years. Can anyone figure out what the problem is?
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You may have hoses misaligned. post a picture and the maker and model number. There is a hose from the tank of course and one from the case body that provide the in and out suction to make the fuel metering have a pressure once running. Your bulb just preloads that process before start. Did everything come from the maker new, bulb included? Have you disassembled the body? Have you opened the screws .75-1.25 rotations? The L screw is most important as it is the low idle or starting flow. If you pressurized the tank does fuel come out the fuel line? Is the pressure return line to the tank functional? It seems to have 3 lines?
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OK, I'm still learning as it seems. I realized now that the tank is in fact pressurized and the lid has to be on and air tight. The tank lid gasked was deformed so I made a new one, filled the tank, put the carb on and, voilà, I could pump up petrol in the bulb. Thanks!
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Oh 2 cycles are never about gas hardly they are always about air and air pressure whether negative or positive. The only time they get terminal is when the main case seal fails and you literally have to take it all apart to fix the vacuum chamber.