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Kawasaki FS730V - new mower - engine issues...
#1
J
JamesBoyd
J
JamesBoyd
Hey Folks!
New member Jim here from SC.
Looking for some advice and help here.
We just bought a place with a 4 acre yard and as such needed a new lawnmower.
We purchased a Kubota Z421 with Kawasaki FS730V. Unit is new and not used.
Unit runs fine at low power demand (less than ¾ throttle and not tall grass) but when run at WOT and/or tall grass – it will run fine for 2-3 mins and then will start to sputter and die… if you disengage the blades and bring it back to ½ throttle, it will surge for a few moments and then smooth out. You can wait for a minute or so and then go back to WOT and start cutting again – and the process repeats itself.
When it just starts to misbehave, if you come all the way off of the throttle, the engine will die. By the time you choke it and turn the key to start, it sits and idles just fine.
I noticed also that the problem seems to be worse if the unit is on an incline.
The Kubota dealers have been little to no help. They report a 2-4 week delay before they can look at the unit and then possible parts delays after that.
Here is what I have done so far:
Removed fuel line from inside the tank to the fuel pump, it is clear and open – no debris in tank, shut off valve is open and lines are clear.
Removed supply line from carb and started the engine – the fuel coming out of pump and headed to carb is flowing well
Added aux tank, ¼” barb, in line fuel filter up above engine (just as a test apparatus) and gravity fed the engine with fuel – problem remained the same
Tested the carb solenoid – appears to be working properly
Removed the main jet, it is not restricted at all
Removed needle and seat, no debris, fuel flows through easily
I do not THINK the problem is electric but don’t want to overlook anything.
The fact that the engine runs fine (even at WOT) for a while – and then when it starts to run poorly - and if the heavy load is removed – the engine will then again start to run fine – makes me think the float bowl is not staying full enough. Also, on an incline, the fuel may come “off” of the main jet a little sooner?
Problem with the float is that it is plastic and does not appear to be adjustable like a metal unit. Float is not fuel logged by the way.
Not sure if the float is “adjustable” in any way?
OK EXPERTS, that is my tale – please help with input if you can?
Yes, I know I should not be working on the unit – but I bought it to cut grass and cannot stomach it sitting at the dealer for 4-6 weeks… and who knows if they will even fix it correctly.
I would even purchase a new carb if I was pretty sure that was the issue – looks like the Kawa replacement is about $250 (would not use an aftermarket). Advice on where to get parts quickly and reasonably priced would be great!
Also I purchased the unit about 150 miles from home, trying not to have to go back to the dealer I bought it from and they would likely tell me the same thing – leave it with us and we will fix it.
Many many thanks!
New member Jim here from SC.
Looking for some advice and help here.
We just bought a place with a 4 acre yard and as such needed a new lawnmower.
We purchased a Kubota Z421 with Kawasaki FS730V. Unit is new and not used.
Unit runs fine at low power demand (less than ¾ throttle and not tall grass) but when run at WOT and/or tall grass – it will run fine for 2-3 mins and then will start to sputter and die… if you disengage the blades and bring it back to ½ throttle, it will surge for a few moments and then smooth out. You can wait for a minute or so and then go back to WOT and start cutting again – and the process repeats itself.
When it just starts to misbehave, if you come all the way off of the throttle, the engine will die. By the time you choke it and turn the key to start, it sits and idles just fine.
I noticed also that the problem seems to be worse if the unit is on an incline.
The Kubota dealers have been little to no help. They report a 2-4 week delay before they can look at the unit and then possible parts delays after that.
Here is what I have done so far:
Removed fuel line from inside the tank to the fuel pump, it is clear and open – no debris in tank, shut off valve is open and lines are clear.
Removed supply line from carb and started the engine – the fuel coming out of pump and headed to carb is flowing well
Added aux tank, ¼” barb, in line fuel filter up above engine (just as a test apparatus) and gravity fed the engine with fuel – problem remained the same
Tested the carb solenoid – appears to be working properly
Removed the main jet, it is not restricted at all
Removed needle and seat, no debris, fuel flows through easily
I do not THINK the problem is electric but don’t want to overlook anything.
The fact that the engine runs fine (even at WOT) for a while – and then when it starts to run poorly - and if the heavy load is removed – the engine will then again start to run fine – makes me think the float bowl is not staying full enough. Also, on an incline, the fuel may come “off” of the main jet a little sooner?
Problem with the float is that it is plastic and does not appear to be adjustable like a metal unit. Float is not fuel logged by the way.
Not sure if the float is “adjustable” in any way?
OK EXPERTS, that is my tale – please help with input if you can?
Yes, I know I should not be working on the unit – but I bought it to cut grass and cannot stomach it sitting at the dealer for 4-6 weeks… and who knows if they will even fix it correctly.
I would even purchase a new carb if I was pretty sure that was the issue – looks like the Kawa replacement is about $250 (would not use an aftermarket). Advice on where to get parts quickly and reasonably priced would be great!
Also I purchased the unit about 150 miles from home, trying not to have to go back to the dealer I bought it from and they would likely tell me the same thing – leave it with us and we will fix it.
Many many thanks!
#2
M
mechanic mark
M
mechanic mark
First & foremost do not mess with it, if they find out, they may void warranty. Next & most important, always use 93 octane gasoline with a quality brand fuel additive.Hey Folks!
New member Jim here from SC.
Looking for some advice and help here.
We just bought a place with a 4 acre yard and as such needed a new lawnmower.
We purchased a Kubota Z421 with Kawasaki FS730V. Unit is new and not used.
Unit runs fine at low power demand (less than ¾ throttle and not tall grass) but when run at WOT and/or tall grass – it will run fine for 2-3 mins and then will start to sputter and die… if you disengage the blades and bring it back to ½ throttle, it will surge for a few moments and then smooth out. You can wait for a minute or so and then go back to WOT and start cutting again – and the process repeats itself.
When it just starts to misbehave, if you come all the way off of the throttle, the engine will die. By the time you choke it and turn the key to start, it sits and idles just fine.
I noticed also that the problem seems to be worse if the unit is on an incline.
The Kubota dealers have been little to no help. They report a 2-4 week delay before they can look at the unit and then possible parts delays after that.
Here is what I have done so far:
Removed fuel line from inside the tank to the fuel pump, it is clear and open – no debris in tank, shut off valve is open and lines are clear.
Removed supply line from carb and started the engine – the fuel coming out of pump and headed to carb is flowing well
Added aux tank, ¼” barb, in line fuel filter up above engine (just as a test apparatus) and gravity fed the engine with fuel – problem remained the same
Tested the carb solenoid – appears to be working properly
Removed the main jet, it is not restricted at all
Removed needle and seat, no debris, fuel flows through easily
I do not THINK the problem is electric but don’t want to overlook anything.
The fact that the engine runs fine (even at WOT) for a while – and then when it starts to run poorly - and if the heavy load is removed – the engine will then again start to run fine – makes me think the float bowl is not staying full enough. Also, on an incline, the fuel may come “off” of the main jet a little sooner?
Problem with the float is that it is plastic and does not appear to be adjustable like a metal unit. Float is not fuel logged by the way.
Not sure if the float is “adjustable” in any way?
OK EXPERTS, that is my tale – please help with input if you can?
Yes, I know I should not be working on the unit – but I bought it to cut grass and cannot stomach it sitting at the dealer for 4-6 weeks… and who knows if they will even fix it correctly.
I would even purchase a new carb if I was pretty sure that was the issue – looks like the Kawa replacement is about $250 (would not use an aftermarket). Advice on where to get parts quickly and reasonably priced would be great!
Also I purchased the unit about 150 miles from home, trying not to have to go back to the dealer I bought it from and they would likely tell me the same thing – leave it with us and we will fix it.
Many many thanks!
First & foremost do not mess with engine,etc, may void warranty. Always use 93 octane gasoline with a quality brand fuel treatment. https://www.lawnmowerforum.com/threads/john-deere-fuel-treatment.56774/#post-343220 Let us know how it goes, thanks, Mark https://www.google.com/search?q=sta...7j35i39j0l6.9732j0j7&sourceid=chrome&ie=UTF-8Hey Folks!
New member Jim here from SC.
Looking for some advice and help here.
We just bought a place with a 4 acre yard and as such needed a new lawnmower.
We purchased a Kubota Z421 with Kawasaki FS730V. Unit is new and not used.
Unit runs fine at low power demand (less than ¾ throttle and not tall grass) but when run at WOT and/or tall grass – it will run fine for 2-3 mins and then will start to sputter and die… if you disengage the blades and bring it back to ½ throttle, it will surge for a few moments and then smooth out. You can wait for a minute or so and then go back to WOT and start cutting again – and the process repeats itself.
When it just starts to misbehave, if you come all the way off of the throttle, the engine will die. By the time you choke it and turn the key to start, it sits and idles just fine.
I noticed also that the problem seems to be worse if the unit is on an incline.
The Kubota dealers have been little to no help. They report a 2-4 week delay before they can look at the unit and then possible parts delays after that.
Here is what I have done so far:
Removed fuel line from inside the tank to the fuel pump, it is clear and open – no debris in tank, shut off valve is open and lines are clear.
Removed supply line from carb and started the engine – the fuel coming out of pump and headed to carb is flowing well
Added aux tank, ¼” barb, in line fuel filter up above engine (just as a test apparatus) and gravity fed the engine with fuel – problem remained the same
Tested the carb solenoid – appears to be working properly
Removed the main jet, it is not restricted at all
Removed needle and seat, no debris, fuel flows through easily
I do not THINK the problem is electric but don’t want to overlook anything.
The fact that the engine runs fine (even at WOT) for a while – and then when it starts to run poorly - and if the heavy load is removed – the engine will then again start to run fine – makes me think the float bowl is not staying full enough. Also, on an incline, the fuel may come “off” of the main jet a little sooner?
Problem with the float is that it is plastic and does not appear to be adjustable like a metal unit. Float is not fuel logged by the way.
Not sure if the float is “adjustable” in any way?
OK EXPERTS, that is my tale – please help with input if you can?
Yes, I know I should not be working on the unit – but I bought it to cut grass and cannot stomach it sitting at the dealer for 4-6 weeks… and who knows if they will even fix it correctly.
I would even purchase a new carb if I was pretty sure that was the issue – looks like the Kawa replacement is about $250 (would not use an aftermarket). Advice on where to get parts quickly and reasonably priced would be great!
Also I purchased the unit about 150 miles from home, trying not to have to go back to the dealer I bought it from and they would likely tell me the same thing – leave it with us and we will fix it.
Many many thanks!
#3
tom3
tom3
Two things I see, internally vented carb, and symptoms of fuel starvation. But I'd get in touch with the dealer, or a rep. from Kubota, and get the mower in the shop and take home a loaner.
#4
cpurvis
cpurvis
I'm with Tom--let Kubota fix it. Also agree with his diagnosis--fuel starvation.
#5
M
mechanic mark
M
mechanic mark
I would return mower & purchase one of their diesel engine models, you'll be glad you did. My nephews dad has at least a dozen Kubota Diesels they use to mow all their properties & have been doing so for at least 20 years. They will not even talk about anything but Kubota mowers with Kubota Diesel Engines. The Japanese make a top quality product in Kubota Diesels.
#6
J
juliechutes
I too had that issue and went through the assigned warranty mechanic. I would never listen to anyone saying, They will void Warranty, when in truth, they will void warranty anyhow. So, why not try and figure it out yourself. After 3691.00 and buying a new engine. No one wants to tell me what was wrong with it. I found pink plastic fibers in the fuel lines from the gasoline tank. I asked the mechanic to replace all hoses because I felt this was leading to the fuel lines from being clogged. Did they replace or even look into the matter? No. I was trying to save you money says the mechanic...? Really, after charging me two shipping fees and $300 over the actual cost of the new engine, Kawasaki attorney says, someone will be in contact with you. I want to know who lied to me. Whose stole money from me. Having been a new widow of one month. This mechanic, two hour drive away, takes my mower for 8 months, lies about just everything he had done on the mower. So, the reality is.. you get screwed over by thieves and liars because your under the fear of not having a warranty and my engine was only 408 hours. No one gives any care or thought to the consumer. Everyone wants to be in your back pocket and take their cut. I finally got my lawnmower back and the moment it's parked in the garage, the floor is covered with oil. they took the original oil drain line, lost the O'ring and I had to order my own drain hose because of the continuous lies that they ordered one and shipped it to me, never arrived.. convenient. In order to use my own lawnmower, having paid for a NEW engine, oil all over the garage floor. I had to fix the issue myself. So, great. I have a running lawnmower.
For the time being. Whether, the original issue is caused by the decline of fuel eating and converting to pink fiber that plugs the fuel system, hard to know. The video on Kawasaki shows that they run air through the engine and have small air ports ejecting grass and debris. That they don't show in their maintenance manual that needs to be blown out and cleaned if grass gets stuck then the debris/dust and dirt can be forced into the engine. The double air filters should keep it clean, but like my lawns, it's bouncy and filters can come loose and if at any time, those filters come loose, you have dust and dirt enter into the engine. Which will void your warranty because you didn't have a filter on the engine. But, again, they don't mention that in the manual. I had a two hundred dollar air filter system by K&N Filters on my engine and was told it was not OEM and voided the warranty. The K&N Filter actually stayed on the mower better than the OEM filter. It's hard to imagine that they would purposely suck air from underneath the mower to run directly into the engine, baffles me, the design and finally understanding the design. I think someone that never mowed a yard, designed his fancy engine to be in a pristine clean room and not actually on dirt and grass.
Good Luck People.
J
juliechutes
Dear James, sort of like a Dear John letter.Hey Folks!
New member Jim here from SC.
Looking for some advice and help here.
We just bought a place with a 4 acre yard and as such needed a new lawnmower.
We purchased a Kubota Z421 with Kawasaki FS730V. Unit is new and not used.
Unit runs fine at low power demand (less than ¾ throttle and not tall grass) but when run at WOT and/or tall grass – it will run fine for 2-3 mins and then will start to sputter and die… if you disengage the blades and bring it back to ½ throttle, it will surge for a few moments and then smooth out. You can wait for a minute or so and then go back to WOT and start cutting again – and the process repeats itself.
When it just starts to misbehave, if you come all the way off of the throttle, the engine will die. By the time you choke it and turn the key to start, it sits and idles just fine.
I noticed also that the problem seems to be worse if the unit is on an incline.
The Kubota dealers have been little to no help. They report a 2-4 week delay before they can look at the unit and then possible parts delays after that.
Here is what I have done so far:
Removed fuel line from inside the tank to the fuel pump, it is clear and open – no debris in tank, shut off valve is open and lines are clear.
Removed supply line from carb and started the engine – the fuel coming out of pump and headed to carb is flowing well
Added aux tank, ¼” barb, in line fuel filter up above engine (just as a test apparatus) and gravity fed the engine with fuel – problem remained the same
Tested the carb solenoid – appears to be working properly
Removed the main jet, it is not restricted at all
Removed needle and seat, no debris, fuel flows through easily
I do not THINK the problem is electric but don’t want to overlook anything.
The fact that the engine runs fine (even at WOT) for a while – and then when it starts to run poorly - and if the heavy load is removed – the engine will then again start to run fine – makes me think the float bowl is not staying full enough. Also, on an incline, the fuel may come “off” of the main jet a little sooner?
Problem with the float is that it is plastic and does not appear to be adjustable like a metal unit. Float is not fuel logged by the way.
Not sure if the float is “adjustable” in any way?
OK EXPERTS, that is my tale – please help with input if you can?
Yes, I know I should not be working on the unit – but I bought it to cut grass and cannot stomach it sitting at the dealer for 4-6 weeks… and who knows if they will even fix it correctly.
I would even purchase a new carb if I was pretty sure that was the issue – looks like the Kawa replacement is about $250 (would not use an aftermarket). Advice on where to get parts quickly and reasonably priced would be great!
Also I purchased the unit about 150 miles from home, trying not to have to go back to the dealer I bought it from and they would likely tell me the same thing – leave it with us and we will fix it.
Many many thanks!
I too had that issue and went through the assigned warranty mechanic. I would never listen to anyone saying, They will void Warranty, when in truth, they will void warranty anyhow. So, why not try and figure it out yourself. After 3691.00 and buying a new engine. No one wants to tell me what was wrong with it. I found pink plastic fibers in the fuel lines from the gasoline tank. I asked the mechanic to replace all hoses because I felt this was leading to the fuel lines from being clogged. Did they replace or even look into the matter? No. I was trying to save you money says the mechanic...? Really, after charging me two shipping fees and $300 over the actual cost of the new engine, Kawasaki attorney says, someone will be in contact with you. I want to know who lied to me. Whose stole money from me. Having been a new widow of one month. This mechanic, two hour drive away, takes my mower for 8 months, lies about just everything he had done on the mower. So, the reality is.. you get screwed over by thieves and liars because your under the fear of not having a warranty and my engine was only 408 hours. No one gives any care or thought to the consumer. Everyone wants to be in your back pocket and take their cut. I finally got my lawnmower back and the moment it's parked in the garage, the floor is covered with oil. they took the original oil drain line, lost the O'ring and I had to order my own drain hose because of the continuous lies that they ordered one and shipped it to me, never arrived.. convenient. In order to use my own lawnmower, having paid for a NEW engine, oil all over the garage floor. I had to fix the issue myself. So, great. I have a running lawnmower.
For the time being. Whether, the original issue is caused by the decline of fuel eating and converting to pink fiber that plugs the fuel system, hard to know. The video on Kawasaki shows that they run air through the engine and have small air ports ejecting grass and debris. That they don't show in their maintenance manual that needs to be blown out and cleaned if grass gets stuck then the debris/dust and dirt can be forced into the engine. The double air filters should keep it clean, but like my lawns, it's bouncy and filters can come loose and if at any time, those filters come loose, you have dust and dirt enter into the engine. Which will void your warranty because you didn't have a filter on the engine. But, again, they don't mention that in the manual. I had a two hundred dollar air filter system by K&N Filters on my engine and was told it was not OEM and voided the warranty. The K&N Filter actually stayed on the mower better than the OEM filter. It's hard to imagine that they would purposely suck air from underneath the mower to run directly into the engine, baffles me, the design and finally understanding the design. I think someone that never mowed a yard, designed his fancy engine to be in a pristine clean room and not actually on dirt and grass.
Good Luck People.
#8
7394
7394
I steer clear of K&N filters for off road lawn use. .. They don't filter well enough imo, they flow like crazy & I use them on the Harley..The K&N Filter actually stayed on the mower
#9
S
slomo
S
slomo
I never buy K&N for anything. On Jeeps and off-road types, there is always a grit trail inside after the filter. Poor filtering is what they are all about.I steer clear of K&N filters for off road lawn use. .. They don't filter well enough, they flow like crazy & I use them on the Harley..