Hi. I have a push lawn mower with a Yamaha MT 110 engin. I just finished servicing it. It runs fine with no blade. As soon as I put the blade on it loses power and runs on low revs even if I it is on full throttle.
Hi. I have a push lawn mower with a Yamaha MT 110 engin. I just finished servicing it. It runs fine with no blade. As soon as I put the blade on it loses power and runs on low revs even if I it is on full throttle.
Yes I did. there is only one gas hose it's fine. I cleaned the carburetor, changed the seels on the carburetor, cleaned the exhaust, put a new spark plug, the compression test was good, did a spark test on ignition coil had good spark.
Sorry forgot to mention, I also cleaned the fuel tank and hose and checked the fuel filter and was still fine.
#6
Richard320
Lack of power under load is some kind of fuel problem.
Start by looking at the throttle linkage and the governor linkage. Nothing binding? Make sure that when you are going full throttle that the carburetor is getting the message and that the cable is adjusted right. Assuming the throttle is opening wide, then you're just starving for gas and I'd doublecheck the float adjustment. And is the carb bowl symmetric? If it needs to be aligned a certain way, that could keep the float from dropping.
In image 091732 you can clearly see where the throttle cable was originally clamped to the throttle arm , about 1/4" from the free end
Higher up the throttle stop has been bent back and is not touching the throttle high speed adjusting bolt .
The triangle tab near the bolt ( top right ) should come around to contact the bent tang behind the throttle plate when the throttle control is at the lowers or stop positon.
The screw should hit the other side of the tang to limit the top speed.
When adjusted like this the spring connecting the throttle plate & the governor arm should be almost loose at minimum revs and around 1/2 as tight as shown in the photo at wide open throttle setting.
#11
StarTech
Well since no one ask I will how was the engine prior to the servicing? This will help to determine if it the current problem was induced during the servicing of the engine or not.
Well since no one ask I will how was the engine prior to the servicing? This will help to determine if it the current problem was induced during the servicing of the engine or not.
I have no idea. The client send us a few lawn mowers that was standing in a store room for a while and yust told us to fix as many of them that is possible.
In image 091732 you can clearly see where the throttle cable was originally clamped to the throttle arm , about 1/4" from the free end
Higher up the throttle stop has been bent back and is not touching the throttle high speed adjusting bolt .
The triangle tab near the bolt ( top right ) should come around to contact the bent tang behind the throttle plate when the throttle control is at the lowers or stop positon.
The screw should hit the other side of the tang to limit the top speed.
When adjusted like this the spring connecting the throttle plate & the governor arm should be almost loose at minimum revs and around 1/2 as tight as shown in the photo at wide open throttle setting.
Then the governor is adjusted backwards.
When you put a load on the engine & it slows down the governor should relax and allow the throttle to open further
So when you have the blade on where is the throttle butterfly on the carb, open fully or closed ?
Without the blade it will happily run at fast idle , around 3000 rpm
When a load ( the blade ) is attached the throttle BUTTERFLY should be opened up further to compensate for the extra load so the engine is now running on the main jet not just the idle jet.
Then the governor is adjusted backwards.
When you put a load on the engine & it slows down the governor should relax and allow the throttle to open further
So when you have the blade on where is the throttle butterfly on the carb, open fully or closed ?
Without the blade it will happily run at fast idle , around 3000 rpm
When a load ( the blade ) is attached the throttle BUTTERFLY should be opened up further to compensate for the extra load so the engine is now running on the main jet not just the idle jet.
It's fully open. I tried it fully open, half open and about less than a 1/4 open. Is it possible that if the shaft is not 100% straight that it can cause this problem? I took off the whole engin nowan saw that the shaft is a bit skew.
Are you sure that the baffle in the exhaust is clean. I had the same problem after 28 years of use. I found that the holes in baffle tube were completely plugged. At another time I found the point gap had closed to almost nothing, but that time it was accompanied by difficulty in starting.
