Help Diagnosing Issue

[slomo]

If I were to sell this mower to another homeowner near me and tell them about the issue, what is a fair asking price in your opinion.

Tell them it's worn out with 2000 hours on it. You pay them to take it off your hands. Used mowers always have some issue. If they ran good they would never get sold.

Why did you ignore Bert and his comments to you? Your next post was about a fuel filter and went on to something else which didn't work either.

 

[poncho144]

I have not been impressed by the Twin 25 hp "K" engine at all after 4 years. The 25 hp "Briggs" on my 12 year old "Snapper" knock-off is superior across the small engine paradigm.
Also, the easily maintainable "S" Hydro trans has proved to be superior as compared to the impossible to maintain Husqvarna.
Get an Ohm reading on both Coils, bet one is bad.....

 

[GrumpyL5030]

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

I wonder if one of the coils fails when it gets hot. Usually they last for better than two years, but who knows the quality of components these days, or how much use your machine has compared to most. Good luck.

 

[slydog]

Coils can go out when engine warms up. Check spark or cylinder activity when engine starts acting up. If it cools down coil most likely will start working again.

I've been reading this post from the beginning, and totally agree on coil theory. I've experienced this mostly on older equipment with high hours on engine, regardless of manuf. As a rule it's a common issue, but coils are unpredictable and can fail at any time. The symptoms indicate a coil, but the excessive fuel and loss of oil indicate your engine may have multiple problems needing attention.

 

[beaverplt]

I had this problem with a Kohler engine of the same model, but older. It turned out the compression of one cylinder was low. Easy to fix if you know how to lap the valves..

 

[riceski@gmail.com]

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

I would check for timing AFTER I pull the gas filter and run it without the filter for 5 min to check for a difference. Some filters are sensitive to water and if you DID have water in the gas or condensation it could mess it up.

 

[ray64]

The symptom's first very much sound like a coil . It is puzzling that if you pull choke it helps . Coils aren't that expensive. I try replacing both coils . If no luck try all new fuel line and maybe even go to an electric low psi pump, with a clear in line filter and look at fuel in filter if acts up to see if filter is full of fuel or not.

 

[TobyU]

I can't wade through all seven pages of these posts but did anything ever get resolved?
My first thought is always when some customer says they clean out the carburetor I just roll my eyes because nine times out of 10 or more like 99 times out of 100, they did not clean it properly because most of them don't even know where the jets are located.
So, I would want to get the engine to where it's not running perfectly and then give it a little bit of choke or use a folded shop cloth to restrict the airflow a little bit to see if that smooths it out..
I would also make sure the fuel cap is venting but that probably has an EPA tank anyways but vacuum building up in the fuel tank can cause funny fuel delivery issues.
Then, the most likely beyond all that would be a call getting hot and breaking down.
I've had two of the newer 7000 series lose a coil or have a coil breakdown when hot.
In this case you're going to have to run it until it starts messing up and then put it in a medium speed and run it on each cylinder by pulling the plug wires off one at a time to see if you can tell if one is weak..
Then I would also be putting a new set of plugs in there and looking at the plugs to read them after a few hours mowing.

Then, check the engine mounting bolts because I find a lot of them that are loose in the engine is rocking back and forth or twisting in other words on a start.

 

[first pull]

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

Replace the carburetor. Sometimes the check valve can be partially blocked and cleaning wont solve it

 

[Tom O']

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

The engine

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

The engine, after warming up, may for some reason be running to lean. If there's a carburetor choke, try closing it slightly to see if there's a noticeable improvement. If there's improvent try a higher octane gas. (As long as it won't damage engine).
Just a thought