really loud like hole in muffler and running horrible

   / really loud like hole in muffler and running horrible #11  

MountainBuck

Silver Member
Joined
Aug 7, 2016
Messages
112
Location
TN
Tractor
Ventrac 4500P; Kubota RTV-X1100C
I am not smart enough to do internal assessment but I think that is my problem. I have super clean air filters and no loose connections at coils or water near plugs.
Does engine rebuild work out very often or is a multi thousand dollar repair? The dealer cannot look at if for two weeks. I’m on a bad way wondering. Thanks for any and all comments

I understand your hesitance.

Back 40 years ago, as a beginner mechanic, I would have changed the plugs and the wires for just a couple of bucks.

The reason I keep thinking about the plugs is that the engine service manual actually calls out the plugs as a reason for the muffler to overheat. You mentioned that you haven't changed the plugs, so it seems like a reasonable place to start.

However, Tomplum is right that there might be something more serious going on.

I would think it should be repairable, but that will take a little more than a high school kid mechanic to do it.

Was it more like a light switch turning off? Like were you mowing fine and then all of the sudden - boom - all of the power dropped out and it was running bad? That would point to more of a serious problem like valves and head gaskets and the like. If so, I would just call the dealer and pay the price. Yes those problems are expensive and with inflation like it is, who knows.

If you take it to the dealer, you should have them quote you on a full service while it is in there, like a full radiator flush and refill, hydraulic fluid service, etc. Yes that will be even more money but cheaper in the long run.
 
   / really loud like hole in muffler and running horrible #12  

prs

Platinum Member
Joined
Apr 30, 2014
Messages
677
Location
Logan, WV
Tractor
JD 650, Ventrac 4500Z AJ02248
Start simple. With engine totally cool, remove the spark plug boots by slightly twisting as you pull. They should be numbered 1-2-3, if not lable them. Use compressed air, even canned air is OK, to blow out the spark plug wells. Remove the spark plugs and inspect for cracked ceramics, damaged gaskets, excess rusting of hex, and gap. If plugs are in poor condition, replace. If rusted, use long swab saturated with KROIL or PB BLaster to clean the spark plug mating seats of the head. If rusted, consider running WITHOUT the rubber bushing that is or should be pressed onto the bottom of each boot. In humid areas, those boots trap condensation as the tractor cools. Do carefully check the two per coil electric connections, they should be very snug without wiggle. Bad plugs let unburned fuel into the catylitic muffler and super heated condtion.

The muffler cover with mineral filled blanket has been replaced by a new all metal shield that comes with fasteners. Much better.

Beyond that, with your mechanical experience, you will need a small engine repair shop and one experienced with Kubota gassers. Or an experienced mechanical friend to help with trouble shooting.

prs
 
   / really loud like hole in muffler and running horrible #13  

prs

Platinum Member
Joined
Apr 30, 2014
Messages
677
Location
Logan, WV
Tractor
JD 650, Ventrac 4500Z AJ02248
phunter; ya dun wint an' jinxed me. lol

I put a long day in HOT weather this past Wednesday mowing tall field fescue. Later in the afternoon I had finished about 11 acres with about 2+ acres to go and my fine running machine suddenly, under only modest load at 3,200RPM, started missing badly and sounded like it had blown part of the head gasket or exhaust manifold gasket. I was at a lower elevation and, like you, was barely able to "limp" back up to the shop building about a quarter mile away. At the shop, she was HOT at the muffler shield (mine is metal) and I had to let it cool to room temp over night before trouble shooting. Yesterday morning the exhaust system was good, the head gasket good, compression good, spark plugs good, fuel and air goo; ignition not so good. Intermittent spark on TWO ignighters (coils), #1 and #3. The 3 cylinder engine was running mostly on just one, the center, cylinder. (#1 being closest to radiator fan, #3 closest to fly wheel, firing order 1-2-3). The outer two cylinders dumping fuel rich exhaust into the catyltic coverter making the heat. I called my dealer and trailered the machine the hour and one half to them. The mechanic said he probably knew the issue, as it was rather common with the Z at about my hour clock (750 hours, I think). He got it to run briefly on all three cylinders by working/jiggeling the wiring harness to the coils. I noticed it had run correctly for brief periods while I was loading it to go there. He replaced the upper press on trigger circuit connectors to those two, but they would still only spark intermittently. I took it off the trailer and into their shop where wiring harness was removed and found to be damaged in its mid section and also at the larger connection at its lower end where it connects to flywheel pick-up sensor. He thought there was a new harness in stock, but there was not. Estimated two weekds to get the new harness from Ventrac, unless they have one in stock. Rats! There are three different lower end mulit-oin connecters, otherwsie I could make a new harness myself.

prs
 
   / really loud like hole in muffler and running horrible #14  

5030

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Feb 21, 2003
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16,090
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Somewhere, but not there....
Tractor
M9000 HDCC3 M9000 HDC
Usually, a hole in a muffler on any 4 stroke engine will cause diminished power output as all 4 stroke gas motors rely on a certain amount of back pressure in the exhaust to run properly.
 
   / really loud like hole in muffler and running horrible
  • Thread Starter
#15  
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phunter

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Joined
Apr 3, 2022
Messages
8
Tractor
john deere 4410
Thanks for the replies. The tractor did act up really quickly. I’m hoping nothing serious since starts easily.

Unfortunately my dad’s health became an issue shortly after my last post. He had to have emergent transfer to Cleveland clinic. Once things are better for him I’ll get things sorted out. Ventrac worries are so small in comparison to the health of your best friend and father. God will see me and my family through.

Once I have a fix determined I’ll share with the group. Thanks again for all your responses.
 
 
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