Sidekick RTV-XG850 backfiring / loss of power

catalyst

Member

Equipment
BX80, RTV-XG850
Sep 30, 2018
67
22
8
St. Clair
I own an RTV-XG850 with ~400 hours on it. It just started having an issue where if I give it full gas, it will backfire and pop and will only accelerate to ~20-22 MPH. It almost feels like governed like when you hit the top end limit ~40 MPH.

It seems to idle perfectly fine and if I barely give it gas it runs fine. I was thinking Fuel Filter or Fuel pump issue, but I saw other threads about ECU power related issues? It seems like incredibly low hours to have a fuel pump issue though.

Any ideas/suggestions?
 

mikester

Well-known member

Equipment
M59 TLB
Oct 21, 2017
3,257
1,734
113
Canada
www.divergentstuff.ca
Did you check for mouse nests in the air box and engine compartment?

You might have a bad ignition coil and are running on one cylinder. Start by checking for loose or damaged wires and then check your plugs.

xg850troubleshoot.jpg
 
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catalyst

Member

Equipment
BX80, RTV-XG850
Sep 30, 2018
67
22
8
St. Clair
air filter looks brand new. i blew it out with air just to be sure. is there any procedure for checking the ignition coils? I'll pull the plugs this weekend to inspect them. I was also going to pull the fuel filter to check that, too.

this thing isn't run very hard. it has had a fairly easy 400 hours just driving around our 15 acre hobby farm.
 

GreensvilleJay

Well-known member

Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
10,346
4,300
113
Greensville,Ontario,Canada
how old is the gas ?
how long has it been sitting since last used ?
how old is the machine ?
how long since carb was tore down/cleaned ?
carbs clog up pretty quick with today's 'great gas'.........
 

catalyst

Member

Equipment
BX80, RTV-XG850
Sep 30, 2018
67
22
8
St. Clair
This is a 2020 RTV-XG850. They are fuel injected.

I use it almost daily, and the gas is less than 2 months old. Mostly short trips taking the kids to the bus stop and back. I know our old RZR would foul out if it had frequent short trips, so pulling the plugs is on my list of things for the weekend if the rain ever stops.

One thing to note - My son left the gas cap off and we noticed it after a day of casually driving it up and down the driveway, so the fuel certainly could have picked up some debris (but it is unlikely), which is why I was going to check the filter and drain the gas just to be safe.

The machine is just outside of the factory warranty date, and is still rather new, so I am a little concerned if the fuel pump is already going or something along those lines. I will pull the plugs this weekend and check them out for fouling and ensure they are both firing.

We did run into a similar issue about 2 months ago. I was pulling a trailer of wood from the sawmill and it wouldn't run past 22mph. I wasn't sure if there is some sort of governor type device that restricts the power under load, or if this is just the same problem I am running into now. Once I unloaded and disconnected the trailer, the XG850 ran perfectly fine again - until now.
 

whitetiger

Moderator
Staff member

Equipment
Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
Nov 20, 2011
2,683
1,186
113
Kansas City, KS
At 400 hours, you are past due for new spark plugs and this engine is hard on plugs.
 
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catalyst

Member

Equipment
BX80, RTV-XG850
Sep 30, 2018
67
22
8
St. Clair
Pulled the plugs - they both look fine and are indeed firing. No excessive fouling and they were not wet.

Since we're nearing 400 hours, I proactively ordered a replacement set of plugs last week and they should be here this coming week - yikes those are expensive plugs! I also ordered the coil packs since they were cheap and to rule those out / keep on hand for spares.

It will idle fine, but if I give it gas, it will backfire. Before it would only backfire when I would floor it, but now it will do it for anything beyond feathering.

When is the easiest way to drain the tank so I can try this again with fresh fuel when the replacement plugs arrive?
 
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whitetiger

Moderator
Staff member

Equipment
Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
Nov 20, 2011
2,683
1,186
113
Kansas City, KS
Is there any type of governor on these that will restrict the speed based on weight like the seatbelts do?
No, there is no limiter that detects the weight of the unit.
There is a PSB regarding the spark plugs.
 

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catalyst

Member

Equipment
BX80, RTV-XG850
Sep 30, 2018
67
22
8
St. Clair
no updates yet. coleman's cancelled my order. looks like the ignition coils jumped up in price to $250. yikes. I was going to proactively order a pair. I guess I will just be checking these with my meter. I will replace the spark plugs and start there, since they are past due. Thank you. Will update as I learn more.
 

Mr. Bull

New member

Equipment
2018 RTV-XG850
May 26, 2023
4
0
1
Mariposa, CA
It seems like incredibly low hours to have a fuel pump issue though.

Any ideas/suggestions?
2018 RTV-XG850 40 hrs. (Yes that's not a typo I got it from a guy on FB Market Place who had 3 acres) I'm having the same issue but more dramatic. No power barely made it back to the garage. It just all of a sudden in mid ascent just lost power. It idles fine between 1200 and 1300 but when I step on the gas it sputters. I am changing the fuel pump this weekend and will follow-up.
 

lugbolt

Well-known member

Equipment
ZG127S-54
Oct 15, 2015
4,950
1,678
113
Mid, South, USA
spark plugs are #1 on these. They're hard on plugs. Replace them don't clean them. You cannot clean spark plugs like 20-30-40 years ago you could. Fuel pressure can cause these type issues as well. there is a fuel filter but it's built into the pump, and to my knowledge kubota don't sell the filter separate from the pump. Most of the time anyway, if the filter is plugged to the point where it's not running properly, the pump and/or regulator are gone anyway. Kawasaki sells the filter for the Mules and replacing it is a normal service item and will save a pump if serviced often. The original pumps, you couldn't get that filter. 2012+ they started offering the filter and pump life increased dramatically so long as people replaced em. Problem is, you have to remove the pump from the tank to get to the filter and with the way things go these days, if it don't come easy people don't do it. That's another reason we've become "a throwaway society".
 
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Mr. Bull

New member

Equipment
2018 RTV-XG850
May 26, 2023
4
0
1
Mariposa, CA
spark plugs are #1 on these. They're hard on plugs. Replace them don't clean them. You cannot clean spark plugs like 20-30-40 years ago you could. Fuel pressure can cause these type issues as well. there is a fuel filter but it's built into the pump, and to my knowledge kubota don't sell the filter separate from the pump.
I changed the fuel pump and that did not fix the issue. It runs a little better. I looked at the spark plugs they look good too.

I'm sending it to the Mechanic. (Annoyed)
 

matt850

New member

Equipment
Kubota sidekick
Jun 13, 2023
4
1
3
pa
Let me throw my 2 cents in. I have a sidekick that cuts out at 22 to 30 MPH. It's been months and I finally talked to a service manager at Messicks in PA. So I tell him what my symptoms are and without hesitating he says they are JUNK! Hide goes on to say people are spending up to 6k to try to solve this and nothing works. He said to go a range hotter on the spark plugs and that the injectors are spraying too much fuel and diluting the oil in some cases the new spark plugs will fix it. He also said that the covid excuse for why they have no new units on the lot is a lie. Kubota has a bad motor problem because they are junk Subaru motors. Ill let you know if the plugs do any good.
 
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Mr. Bull

New member

Equipment
2018 RTV-XG850
May 26, 2023
4
0
1
Mariposa, CA
It did end up being the spark plugs that fixed my issue. I did not send it to the mechanic. It runs great now but wow 45 hours and needed new plugs??? As you can see in the picture the one was dirty and had a tar like substance on it. I also filled up the tank with fresh fuel and added a bunch of fuel injector cleaner.
 

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mikester

Well-known member

Equipment
M59 TLB
Oct 21, 2017
3,257
1,734
113
Canada
www.divergentstuff.ca
Let me throw my 2 cents in. I have a sidekick that cuts out at 22 to 30 MPH. It's been months and I finally talked to a service manager at Messicks in PA. So I tell him what my symptoms are and without hesitating he says they are JUNK! Hide goes on to say people are spending up to 6k to try to solve this and nothing works. He said to go a range hotter on the spark plugs and that the injectors are spraying too much fuel and diluting the oil in some cases the new spark plugs will fix it. He also said that the covid excuse for why they have no new units on the lot is a lie. Kubota has a bad motor problem because they are junk Subaru motors. Ill let you know if the plugs do any good.
So far so good on my subaru motor but she's a thirsty girl. If I could find a small diesel engine to replace it with I'd be a happy camper. I looked at electric conversion kits but it's cheaper to buy a new UTV.