JD X580 using a lot of gas when mowing.

[Tiger Small Engine]

When you get more hours on the engine, it should get better on gas.. Both my Kawasaki's did..

And as to the one plug showing richer. the crankcase vent is on the R. side of the intake manifold to engine..Least mine is.

Always run a small engine at wide open throttle. 2800 RPMs isn’t going to give you the quality of cut, be good on the hydros, or keep the oil and fan circulating like you need.

 

[slomo]

Always run a small engine at wide open throttle. 2800 RPMs isn’t going to give you the quality of cut, be good on the hydros, or keep the oil and fan circulating like you need.

What he said.

 

[7394]

Always run a small engine at wide open throttle. 2800 RPMs isn’t going to give you the quality of cut, be good on the hydros, or keep the oil and fan circulating like you need.

Why ya quote me ?

 

[johnorlandi]

called the dealer.
Consensus in the shop is one of two options- Running on the one cylinder only, or over fueling- Both options have several things to look at, so can't give an accurate "this is it" from the spark plug pics.

Welcome to bring it down, or we can come and get it.

going in Tuesday will let you know what they find if anything.

 

[Cajun power]

Pull the plugs and take a look at their color. If they are black and have a carbon build up, the engine is running rich and needs to be adjusted. If they are not black it looks like you will have to live with it. As a side note, I have my doubts about your dealer. I’ve always instructed my customers to cut at full throttle, that’s is where the unit is designed to do its best work.

wide open throttle, all the time. Same experience. I would just add that usually a rich running engine will also blow sooty black exhaust. If you place a piece of carboard taped to part of the frame where the exhaust blows out, over time it will turn very black and have a sooty almost dusty like coating.

 

[Cajun power]

here are some of the things that can cause a mower engine to run rich:

malfunctioned carb...maybe some factory mistake? maybe the main jet lost a rubber seal or even missing? there is a hidden air needle "valve"..usually located at the top of the carb, sometimes covered by a dummy welch plug. (this is rare, but sometimes the factory sets this hidden air needle "valve" incorrectly...

the choke valve might be stuck closed or will not open all the way...restricting the flow of air into the carb

the air filter is fouled, or something within the air filter box and plenum is blocking air flow.

fuel leak somewhere? look for any kind of pin hole in fuel lines, or leaking fuel line connections to the tank, fuel filter, fuel pump, carb. Especially notice the fuel line rubber grommet that connects to the tank....make sure fuel is not leaking there or from a tank leak or a loose cap where fuel sloshes up and out or evaporates when stored.

weak spark plug ...gap might be too wide...or inadequate ignition module energy..

does the oil smells like fuel? is it thin and runny? if so, it's possible that fuel is getting past the piston rings into the crank case. the piston rings need to be staggered ..they the butt ends all line up, you can have unburned fuel getting past the rings. But usually if this is excessive it will cause engine performance problems like low power...or surging.and the governor surging...excessive oil in the oil breather that reaches the air filter may be due to overfill of oil, but can also be fuel getting past the piston into the crank

valves are not lashed properly, or automatic compression release device on cam is borked. If the valves are not set correctly....even just one valve in one cylinder can cause a 4 cycle timing problem...usually this presents also as a drop in performance, misfires, surging. A leak down test for bad valve lash and worn or incorrectly installed piston rings can help identify the problems without removing the head cylinders.

and finally...

 

[GrumpyCat]

My FR600V 18 hp Kawasaki consumes 1/2 gallon per hour at full throttle.

 

[7394]

the air filter is fouled, or something within the air filter box and plenum is blocking air flow.

That would affect both spark plugs, not just one....

 

[Cajun power]

for reference the fr730V should consume about 1.2-1.6 gallons per hour. It all depends on the weight of the machine plus rider AND pto/blade/hydro load. Your JD in base model, no implements, towing nothing, weighs 777 pounds with no fuel in the tank. You are probably near 950-1000 pounds of weight after fuel and rider. So i would imagine a 25 hp naturally aspirated v twin kawasaki is going to consume at least the upper end of that 1.6 gallons per hour. My opinion is that if it's over 2.0 gallons an hour, there is definitely something wrong going on and that cannot be related to new engine breakin...you would never see a factory engine consuming so much fuel during engine breakin. You might have a factory dud! If you have a warranty, I would take it back and have them do a full test of every single load bearing system..spark plugs out and free hand the rotation to see if there is unusual resistance to rotation....leak down test...carb test...static and dynamic...see if the hydros are borked (unloaded off the ground)...axles/bearings....pto engagement and bearing problems...is the deck hydrodraulic lift system operating correctly...then do a tank and fuel line test...look for leaks.

something is definitely wrong and you should not be consuming that much fuel in a new machine, even at nearly 1,000 pounds.

 

[Cajun power]

for reference the fr730V should consume about 1.2-1.6 gallons per hour. It all depends on the weight of the machine plus rider AND pto/blade/hydro load. Your JD in base model, no implements, towing nothing, weighs 777 pounds with no fuel in the tank. You are probably near 950-1000 pounds of weight after fuel and rider. So i would imagine a 25 hp naturally aspirated v twin kawasaki is going to consume at least the upper end of that 1.6 gallons per hour. My opinion is that if it's over 2.0 gallons an hour, there is definitely something wrong going on and that cannot be related to new engine breakin...you would never see a factory engine consuming so much fuel during engine breakin. You might have a factory dud! If you have a warranty, I would take it back and have them do a full test of every single load bearing system..spark plugs out and free hand the rotation to see if there is unusual resistance to rotation....leak down test...carb test...static and dynamic...see if the hydros are borked (unloaded off the ground)...axles/bearings....pto engagement and bearing problems...is the deck hydrodraulic lift system operating correctly...then do a tank and fuel line test...look for leaks.

something is definitely wrong and you should not be consuming that much fuel in a new machine, even at nearly 1,000 pounds.

also look at each blade spindle and free spin them..same with belt tensioner...should all spin freely with little resistance.

the reason I posted this? you may be seeing normal spark plug wear during breakin and thinking it's an engine related problem. it could be the engine is running as it should but under some unknown high load.

tip: I have installed temp sensors in all my mowing machines (exmark, bad boy, dixie chopper (vintage silver eagle with the generac engines and generac hydros), and a junky cub cadet ultima zt1). it's a good idea to have some means to see what the heat cycles are during the triple digits hot ass days during summer here in south louisiana. it's heat that kills these air cooled engines. There are many youtube videos showing how to install these temp sensors and wiring them up and putting a gauge in the control panels. Easy to do and can help prevent a big ticket day. Also give you a baseline to know where the engine temp ranges are normal and you can use that to track how things perform over time. Surprising how much heat builds on old oil and dusty dirty cylinder fins!