help with my two stroke????
Discussion
Hi
any ideas whats wrong with my petrol flymo?.
Its 2 stroke.
I stripped the carb twice and cleaned.
Runs for sometimes 2-3mins and sometimes 2-3 seconds but cant get it to run constantly.
i used fourstar this time.
Could this be the problem?
i assumed this would be better for it.
I think the faster the motor runs on these the more fuel is pumped as they do not have a seperate fuel pump.
It just dies slowley!!!!!!!
pain in the grass!!!!!!!
any ideas whats wrong with my petrol flymo?.
Its 2 stroke.
I stripped the carb twice and cleaned.
Runs for sometimes 2-3mins and sometimes 2-3 seconds but cant get it to run constantly.
i used fourstar this time.
Could this be the problem?
i assumed this would be better for it.
I think the faster the motor runs on these the more fuel is pumped as they do not have a seperate fuel pump.
It just dies slowley!!!!!!!
pain in the grass!!!!!!!
nico1 said:
Hi
any ideas whats wrong with my petrol flymo?.
Its 2 stroke.
I stripped the carb twice and cleaned.
Runs for sometimes 2-3mins and sometimes 2-3 seconds but cant get it to run constantly.
i used fourstar this time.
Could this be the problem?
i assumed this would be better for it.
I think the faster the motor runs on these the more fuel is pumped as they do not have a seperate fuel pump.
It just dies slowley!!!!!!!
pain in the grass!!!!!!!
a) I would imagine the jets/and/or fuel line are blocked with congealed two stroke fuel settled over winter.......
b) Make sure the air filter is clean
c) Always wise to fit a NEW spark plug at the start of every season.....
I would say it's definitely a fuel starvation problem......
Any reputable lawn mower specialist should sort it out in 15 minutes.............
Just reminded me, my petrol Flymo wouldn't start last week..............
I've been using petrol flymo's for years. I swear by them, but you do have to look after them in a way that you wouldn't a four stroke.
The petrol flymo has an air driven governor, which usually causes exactly this problem.
The throttle on the carb is connected to a vane which sits next to the cap on the engine, under the cowl.
The cap is the bit with the magnet for the magneto.
The cap also has fins on it which cause air to be drawn in through the mesh on the top of the engine and pushed against the throttle vane. These fins are not to be confused with the fins on the bottom of the engine wich push air under the hood and keep the mower afloat.
If the engine speed rises too far the air pressure on the throttle vane rises, and closes the throttle. If the engine speed falls, the air pressure falls on the throttle vane and a spring pulls the throttle open again.
The vane it's self is made of aluminium, and is a close fit between the cowl and the engine cap/magnet. Often the fit becomes an interference one (bits of grass or dents in the cowl), and the throttle gets stuck at a particular setting. You would be unlikely to notice this even if you strip the carb. This is because the vane drives the throttle through a pin onto the lever on the carb. You can remove the whole carb without removing the cowl or inspecting the vane.
Other problems that can also occur.......
If you have an allen with a tecumseh engine, there is a knurled screw on the fuel filler cap. The screw is a valve that lets air into the fuel tank. Obviously the fuel pipe to the carburettor must be open, but also the valve in the fuel cap.
Another problem peculiar to two strokes is fuel evaporation. When you finish with the mower, shut the fuel valve at the tank, and wait for the engine to stop as a result of fuel starvation. If you don't, the fuel will evaporate in the carb, and leave the oil as a residue. This residue makes starting difficult, and can block the jets.
The HT lead from the magneto, to the spark plug, is usually copper cored, and the spark plug cap is screwed into the lead. Often, the core of the lead will break, leading to a less than perfect connection between the spark plug and the magneto. This is usually only fixed by replacing the spark plug lead. IIRC the lead is permanantly secured to the magneto, so you also have to buy a replacement magneto.
In my own experience, if you starve the engine of fuel when you shut it down, very little ever goes wrong with the carb. The vane and the linkage to the carb easily clog with grass, and must be kept clean to keep the mower running correctly.
Edited to add>>
If you have a very new mower, things may be different. I just looked at the website, and the design has changed recently.
>> Edited by dilbert on Friday 13th May 23:54
The petrol flymo has an air driven governor, which usually causes exactly this problem.
The throttle on the carb is connected to a vane which sits next to the cap on the engine, under the cowl.
The cap is the bit with the magnet for the magneto.
The cap also has fins on it which cause air to be drawn in through the mesh on the top of the engine and pushed against the throttle vane. These fins are not to be confused with the fins on the bottom of the engine wich push air under the hood and keep the mower afloat.
If the engine speed rises too far the air pressure on the throttle vane rises, and closes the throttle. If the engine speed falls, the air pressure falls on the throttle vane and a spring pulls the throttle open again.
The vane it's self is made of aluminium, and is a close fit between the cowl and the engine cap/magnet. Often the fit becomes an interference one (bits of grass or dents in the cowl), and the throttle gets stuck at a particular setting. You would be unlikely to notice this even if you strip the carb. This is because the vane drives the throttle through a pin onto the lever on the carb. You can remove the whole carb without removing the cowl or inspecting the vane.
Other problems that can also occur.......
If you have an allen with a tecumseh engine, there is a knurled screw on the fuel filler cap. The screw is a valve that lets air into the fuel tank. Obviously the fuel pipe to the carburettor must be open, but also the valve in the fuel cap.
Another problem peculiar to two strokes is fuel evaporation. When you finish with the mower, shut the fuel valve at the tank, and wait for the engine to stop as a result of fuel starvation. If you don't, the fuel will evaporate in the carb, and leave the oil as a residue. This residue makes starting difficult, and can block the jets.
The HT lead from the magneto, to the spark plug, is usually copper cored, and the spark plug cap is screwed into the lead. Often, the core of the lead will break, leading to a less than perfect connection between the spark plug and the magneto. This is usually only fixed by replacing the spark plug lead. IIRC the lead is permanantly secured to the magneto, so you also have to buy a replacement magneto.
In my own experience, if you starve the engine of fuel when you shut it down, very little ever goes wrong with the carb. The vane and the linkage to the carb easily clog with grass, and must be kept clean to keep the mower running correctly.
Edited to add>>
If you have a very new mower, things may be different. I just looked at the website, and the design has changed recently.
>> Edited by dilbert on Friday 13th May 23:54
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