Sidekick RTV-XG850 backfiring / loss of power

catalyst

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BX80, RTV-XG850
Sep 30, 2018
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Well mine is still pouring gas in the crankcase and even still under warranty Kubota is ignoring it. I have emails from others with similar problems and am thinking there may be major design issues with the Subaru engine Kubota is trying to hide. Just got an email from a guy saying a replacement starter for them is $700.00 just to buy if you can find one. I made a big mistake being loyal to Kubota. Awful lot of low hour used ones available and I wonder why.
so what are they even doing about your problem to rectify it? I am debating on contacting our state's atty general's office, or the state's consumer protection group. I feel like this machine is nearly new - only 2 years old with 400 hours on it under 1k miles. That is under the max mileage for warranty coverage!!!

I dont understand how a machine like this has a major mechanical failure in such a short span. It would be different if we had racked up hours or miles on it, but it is barely broken in.
 

Sidekick

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RTV-X, BX3260, Z726XKW-3-60, Deere 4100
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so what are they even doing about your problem to rectify it? I am debating on contacting our state's atty general's office, or the state's consumer protection group. I feel like this machine is nearly new - only 2 years old with 400 hours on it under 1k miles. That is under the max mileage for warranty coverage!!!

I dont understand how a machine like this has a major mechanical failure in such a short span. It would be different if we had racked up hours or miles on it, but it is barely broken in.
They are doing nothing. It spent 10 weeks at the dealer the end of last summer. Kubota would only approve a simple compression test, fuel injector replacement and oil change. Dealer ran it a couple hours and the oil level went up slightly. They were talking about maybe it was the ECU but Kubota told it wouldn't do anything and swapping the engine would be the same results because of what they call short tripping. That is when the Subaru engine is run less then 20 minutes after each start to evaporate the fuel the high compression engine puts in the oil each start. Finally after 8 weeks they approved sending the oil out to be analyzed ( the first change at 20 hours and the second at 25) Results came back with concernable gas contamination and moisture in the oil. Kubota told the dealer to return it and on the paperwork it said it was caused by short tripping and I have to run it 10 hours with no short tripping then it will be tested again. The blame was put on me for running it on a 10 acre homestead and mostly using it for 10 to 15 minutes at a time. No other work or testing was approved for it. Got it back oil level was high, oil thin, greyish, and a very strong fuel smell. I have only run it a couple times since and level is higher. Worried about permeant damage that Kubota doesn't seem to care about. Dealership owner told me the best thing do is run it hard with the gas in the oil and try to blow it so Kubota has to do something about the problem that they seem to be ignoring and blaming on the buyer even though nothing like this was stated up front. I take good care of all my equipment and won't do that. I contacted Kubota Cares and they say it is in the dealers hands and the dealer says Kubota has to approve any work so they get paid and Kubota says it's normal for this engine and won't approve anything. It is a 2022 with 30 hours on it now because I am afraid to drive it. What a mistake I made being loyal to Kubota as they don't care anymore. I wonder if that may be the cause of your premature engine failure. Most people have dealers change the oil and problems like this can go unnoticed to eventually cause failure. Warranty expires May and if they continue to blame it on a term they made up then I will start exploring legal options. Sorry for the long rant but I am broken hearted over this.
 

Siesta Sundance

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They are doing nothing. It spent 10 weeks at the dealer the end of last summer. Kubota would only approve a simple compression test, fuel injector replacement and oil change. Dealer ran it a couple hours and the oil level went up slightly. They were talking about maybe it was the ECU but Kubota told it wouldn't do anything and swapping the engine would be the same results because of what they call short tripping. That is when the Subaru engine is run less then 20 minutes after each start to evaporate the fuel the high compression engine puts in the oil each start. Finally after 8 weeks they approved sending the oil out to be analyzed ( the first change at 20 hours and the second at 25) Results came back with concernable gas contamination and moisture in the oil. Kubota told the dealer to return it and on the paperwork it said it was caused by short tripping and I have to run it 10 hours with no short tripping then it will be tested again. The blame was put on me for running it on a 10 acre homestead and mostly using it for 10 to 15 minutes at a time. No other work or testing was approved for it. Got it back oil level was high, oil thin, greyish, and a very strong fuel smell. I have only run it a couple times since and level is higher. Worried about permeant damage that Kubota doesn't seem to care about. Dealership owner told me the best thing do is run it hard with the gas in the oil and try to blow it so Kubota has to do something about the problem that they seem to be ignoring and blaming on the buyer even though nothing like this was stated up front. I take good care of all my equipment and won't do that. I contacted Kubota Cares and they say it is in the dealers hands and the dealer says Kubota has to approve any work so they get paid and Kubota says it's normal for this engine and won't approve anything. It is a 2022 with 30 hours on it now because I am afraid to drive it. What a mistake I made being loyal to Kubota as they don't care anymore. I wonder if that may be the cause of your premature engine failure. Most people have dealers change the oil and problems like this can go unnoticed to eventually cause failure. Warranty expires May and if they continue to blame it on a term they made up then I will start exploring legal options. Sorry for the long rant but I am broken hearted over this.
Run gear oil in it.
Rent one from that dealer and perform an engine swap.
 
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jimh406

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I didn't read the entire thread, but I'd try running Sea-foam in it with new fuel or try a different dealer. In my experience with other types of vehicles, some dealers don't seem to be very good at diagnosis of rare issues.
 
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Sidekick

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I didn't read the entire thread, but I'd try running Sea-foam in it with new fuel or try a different dealer. In my experience with other types of vehicles, some dealers don't seem to be very good at diagnosis of rare issues.
I doubt the outcome would be any different at another dealer in the area because of a similar case just west of me and the same rep. A 19 sidekick with low hours with oil contamination. The result for the owner was the same as mine saying it is normal for this engine for short tripping and he was to blame. My dealer mentioned this to me after the rep said the same about mine. I have since been in contact with the owner and nothing was ever done so he wound up dumping his. Kubota knows about this as my mechanic said it was mentioned at a seminar but the solution was a redesigned intake manifold that never happened. So it seems they just don't want to deal with problems on a engine they didn't manufacture. These are not good for a homestead as advertised having the requirement to be run for at least 20 to 30 minutes after each start. Had that been advertised I would have never touched it. Kubota has the final word on what the warranty covers and this must come from up above in the corporate ladder.
 

catalyst

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BX80, RTV-XG850
Sep 30, 2018
67
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8
St. Clair
Here is our Diagnostic data from the dealer on our RO. I don't entirely understand the spark plug comment, because we just put in new plugs and they were torqued properly and fine...


Mag side spark plug separated at threads. Identified that engine bogs down after unit has come to operating temperature and throttle is
depressed more than ~60%. Checked valve clearance, spark plug gap, spark quality, fuel pressure, engine compression, and throttle
position sensor. No defects were identified. Inspected CVT clutches and was unable to identify any defects. Scanned ECU with ACE
diagnostic tool and found no active fault codes. Used ACE to monitor engine and verified appropriate signals being received from fuel
injectors and throttle position sensor. Engine will operate at rated speeds while cold and when not under load. Have forwarded case to
Kubota TSC, Currently waiting for response on further diagnostic and troubleshooting steps.
After performing tests requested by kubota support was advised to inspect valves and valve seats. Request authorization to remove head
to inspect valves and valve seats.
After consulting with regional field service rep and performing another hot compression test. Found cylinder 1 only building 90 PSI
performed a wet compression test and found cylinder 1 building 150 PSI. Removed oil fill cap to feel for blow by and did identify large
amount of exhaust gas coming from oil fill. also identified strong fuel smell from oil. Checked oil level and identified oil level is
approximately half quart over level. suspect over fill is from fuel contaminating oil. Recommend replacing cylinder
 
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catalyst

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BX80, RTV-XG850
Sep 30, 2018
67
22
8
St. Clair
They are doing nothing. It spent 10 weeks at the dealer the end of last summer. Kubota would only approve a simple compression test, fuel injector replacement and oil change. Dealer ran it a couple hours and the oil level went up slightly. They were talking about maybe it was the ECU but Kubota told it wouldn't do anything and swapping the engine would be the same results because of what they call short tripping. That is when the Subaru engine is run less then 20 minutes after each start to evaporate the fuel the high compression engine puts in the oil each start. Finally after 8 weeks they approved sending the oil out to be analyzed ( the first change at 20 hours and the second at 25) Results came back with concernable gas contamination and moisture in the oil. Kubota told the dealer to return it and on the paperwork it said it was caused by short tripping and I have to run it 10 hours with no short tripping then it will be tested again. The blame was put on me for running it on a 10 acre homestead and mostly using it for 10 to 15 minutes at a time. No other work or testing was approved for it. Got it back oil level was high, oil thin, greyish, and a very strong fuel smell. I have only run it a couple times since and level is higher. Worried about permeant damage that Kubota doesn't seem to care about. Dealership owner told me the best thing do is run it hard with the gas in the oil and try to blow it so Kubota has to do something about the problem that they seem to be ignoring and blaming on the buyer even though nothing like this was stated up front. I take good care of all my equipment and won't do that. I contacted Kubota Cares and they say it is in the dealers hands and the dealer says Kubota has to approve any work so they get paid and Kubota says it's normal for this engine and won't approve anything. It is a 2022 with 30 hours on it now because I am afraid to drive it. What a mistake I made being loyal to Kubota as they don't care anymore. I wonder if that may be the cause of your premature engine failure. Most people have dealers change the oil and problems like this can go unnoticed to eventually cause failure. Warranty expires May and if they continue to blame it on a term they made up then I will start exploring legal options. Sorry for the long rant but I am broken hearted over this.
My problem sounds almost the same, except they want to redo cyl 1 on mine.
 
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Sidekick

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My problem sounds almost the same, except they want to redo cyl 1 on mine.
All the invoice for mine said:

Warranty
Replace spark plugs, replace fuel injectors (high level of gas in oil sample) Test head gasket, send oil samples out.
KUBOTA STATES MACHINE MUST REACH FULL OPERATING TEMPERATURE/ DO NOT SHORT TRIP. RUN MACHINE ADDITIONAL 10 HOURS AND SEND OIL SAMPLE OUT AGAIN

There were no results stated about the results of any testing. Only a statement that it runs fine.

There were no dates other then the return date. I was told every time started it must run for at least 20 minutes to reach full operating temperature or it will not evaporate the gas from the oil. The dealer ran the machine almost 4 hours of full operating temp prior to returning it and there was overfill and dilution at drop off that no one seemed worried about. The Kubota technical department called all the shots and limited what the dealer was allowed to touch.
I was told it is normal for these engines to blow fuel in the oil if short tripped. Was over 12 ounces overfilled at the 20 hour oil change and the sample separated into 3 definite layers. Thick white sludge on the bottom, thin grey oil in the middle, and a thick layer of gasoline on top. Kubota originally said that is normal for these engines, nothing to look at. Finally after contacting Kubota Cares a case was set up but has never been mentioned in the paperwork I received.

I contacted Kubota Cares to report it was in the same condition when returned an when it went in and zero response that time.

The other like it near me had similar problems.
 

catalyst

Member

Equipment
BX80, RTV-XG850
Sep 30, 2018
67
22
8
St. Clair
I submitted the following questions back to the dealer and we are waiting on a response from Kubota.
1. How much is owed and what is the breakdown and results for diagnostics performed?
2. I see "Mag side spark plug separated at threads." What does that mean? (Our spark plugs were just changed and installed per the torque specs provided earlier in this thread, so I am a little upset if they ruined one of the plugs from improper assembly.
3. If any repairs are made, what is the warranty period on that repair and is that a warranty through Kubota, or the dealership?

As a general comment, from the inspection report, it sounds like there is 1/2 quart of gas in our oil if the oil level is currently 1/2 quart high. I am astonished the engine is dumping that much gas into the engine and thinning the oil, causing premature failure. This is such an utter mess. The comical piece of this is - we asked for a quote on getting an entire engine replacement if we wanted to move away from the problematic Subaru motor - that quote was almost $12,000.

We bought this machine because Kubota has always been a symbol of reliability and quality. The fact that Kubota is basically leaving us out to dry on a 2-3 year old machine with under 400 hours on it is astonishing. We live on a small homestead with 15 acres. This machine has only been used with light upkeep of the property, but a lot of the usage is indeed short trips back and forth to get the mail, or to drop the kids off at the end of our 1/4 mile driveway each morning. Our machine indeed sees a lot of "short tripping", and this is primarily one of the reasons we went with a gas model over the diesel variant.

Shame on Kubota for not standing behind the product at this point.
 

Sidekick

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RTV-X, BX3260, Z726XKW-3-60, Deere 4100
Jul 29, 2023
286
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I submitted the following questions back to the dealer and we are waiting on a response from Kubota.
1. How much is owed and what is the breakdown and results for diagnostics performed?
2. I see "Mag side spark plug separated at threads." What does that mean? (Our spark plugs were just changed and installed per the torque specs provided earlier in this thread, so I am a little upset if they ruined one of the plugs from improper assembly.
3. If any repairs are made, what is the warranty period on that repair and is that a warranty through Kubota, or the dealership?

As a general comment, from the inspection report, it sounds like there is 1/2 quart of gas in our oil if the oil level is currently 1/2 quart high. I am astonished the engine is dumping that much gas into the engine and thinning the oil, causing premature failure. This is such an utter mess. The comical piece of this is - we asked for a quote on getting an entire engine replacement if we wanted to move away from the problematic Subaru motor - that quote was almost $12,000.

We bought this machine because Kubota has always been a symbol of reliability and quality. The fact that Kubota is basically leaving us out to dry on a 2-3 year old machine with under 400 hours on it is astonishing. We live on a small homestead with 15 acres. This machine has only been used with light upkeep of the property, but a lot of the usage is indeed short trips back and forth to get the mail, or to drop the kids off at the end of our 1/4 mile driveway each morning. Our machine indeed sees a lot of "short tripping", and this is primarily one of the reasons we went with a gas model over the diesel variant.

Shame on Kubota for not standing behind the product at this point.
That sure sounds exactly like my problem. I bought mine for a 10 acre homestead to drag firewood out of the woods, plow snow, and ride around with the grandchildren. Oil went up about 6 ounces every 10 hours of runtime. Hardly ever ran it the 20 to 30 minutes they now say after each start to reach full operating temperature. Same with the guy west of me. Kubota says that happens with short tripping and I bet there are many more out there that are ticking time bombs because it is not a documented defect that has to be declared at resale. Sounds like it mostly affects machines sold in colder climates. Right now I was told it's my fault for using it like I bought it to use with no warnings about this at the time of sale. Really surprised even Kubota Cares is ignoring this issue now. It sucks to be stuck in this position with a machine that I love but know it won't last without oil changes every 5 hours. Was going to replace my BX in the spring but now will probably go back to Deere.
Deere.
 

catalyst

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Equipment
BX80, RTV-XG850
Sep 30, 2018
67
22
8
St. Clair
That sure sounds exactly like my problem. I bought mine for a 10 acre homestead to drag firewood out of the woods, plow snow, and ride around with the grandchildren. Oil went up about 6 ounces every 10 hours of runtime. Hardly ever ran it the 20 to 30 minutes they now say after each start to reach full operating temperature. Same with the guy west of me. Kubota says that happens with short tripping and I bet there are many more out there that are ticking time bombs because it is not a documented defect that has to be declared at resale. Sounds like it mostly affects machines sold in colder climates. Right now I was told it's my fault for using it like I bought it to use with no warnings about this at the time of sale. Really surprised even Kubota Cares is ignoring this issue now. It sucks to be stuck in this position with a machine that I love but know it won't last without oil changes every 5 hours. Was going to replace my BX in the spring but now will probably go back to Deere.
Deere.
it is funny you mention that... we also have a BX1880 and were looking to replace it next year with a larger machine.
 
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GreensvilleJay

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late in the game and do not know the machine but..
re: gas in oil

Is there a shut off valve in the gas line between gas tank and engine ?

I ask because I've seen a lot of riders with gas in oil sump, caused by gravity pushing gas through carb,past rings, into oil sump. 'cure' has always been to add a shutoff valve. Yes, PITA to always turn on to run, off to store but it 'solves' the gas in oil problem...
 

jimh406

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I agree that the RTV is a disappointment.

If there is no warranty, I guess I'd look into an independent shop if you can't do the work.
 

Sidekick

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Jul 29, 2023
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late in the game and do not know the machine but..
re: gas in oil

Is there a shut off valve in the gas line between gas tank and engine ?

I ask because I've seen a lot of riders with gas in oil sump, caused by gravity pushing gas through carb,past rings, into oil sump. 'cure' has always been to add a shutoff valve. Yes, PITA to always turn on to run, off to store but it 'solves' the gas in oil problem...
No shutoff high pressure fuel injection system and the injectors were checked for leakage before replacing. Kubota said it is caused by short tripping with this engine after mine was 10 weeks in the shop.
 

Sidekick

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I agree that the RTV is a disappointment.

If there is no warranty, I guess I'd look into an independent shop if you can't do the work.
2 of us that bought machines were told it is caused by short tripping and no real fix if you don't run it at least 20 minutes after each start to full operating temperature to evaporate the fuel off. Poor excuse for a machine sold to homesteaders with smaller properties.
 

GreensvilleJay

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hmm, now I'm real curious.
'short tripping'..... so engine's not 'hot'... ok , in the 'cool' engine HOW does gas get into the oil ?
How does Kubota explain the transfer ?? head not torqued properly, bad gaskets, ????
Hmm..does this happen to ALL of them, or say just a series made between xx and yy, using zz parts ??
 

Siesta Sundance

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That sure sounds exactly like my problem. I bought mine for a 10 acre homestead to drag firewood out of the woods, plow snow, and ride around with the grandchildren. Oil went up about 6 ounces every 10 hours of runtime. Hardly ever ran it the 20 to 30 minutes they now say after each start to reach full operating temperature. Same with the guy west of me. Kubota says that happens with short tripping and I bet there are many more out there that are ticking time bombs because it is not a documented defect that has to be declared at resale. Sounds like it mostly affects machines sold in colder climates. Right now I was told it's my fault for using it like I bought it to use with no warnings about this at the time of sale. Really surprised even Kubota Cares is ignoring this issue now. It sucks to be stuck in this position with a machine that I love but know it won't last without oil changes every 5 hours. Was going to replace my BX in the spring but now will probably go back to Deere.
Deere.
Quite kicking this can around.
Run heavy weight oil in it!
SAE 50 OR Higher.
 
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jimh406

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2 of us that bought machines were told it is caused by short tripping...
Seems like they should have recalled them. You just have to wonder how many do they want to fail before the recall?
 

Sidekick

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Seems like they should have recalled them. You just have to wonder how many do they want to fail before the recall?
I was told there isn't a fix by the mechanic. If they replaced the engine it wouldn't change a thing when not brought to full operating temp every start. Kubota turned down the original warranty claim the dealer put in saying it is normal for these machines when short tripped. They finally opened one when the dealer showed them the oil but Kubota denied testing the samples for 8 weeks. I believe they are hiding something about this as they are not approving any more testing at this point. Plus it was returned with contamination after the dealer ran it a couple hours hot that should have been noted. Wish Kubota would chime in.