Zero Turn power

[redneck1952]

I have a Toro zero turn ZX4800 that loses RPM when the blade is engaged. It will not handle heavy grass at all. The fuel filter, fuel pump and spark plug has been replaced with zero effects. The mower has always had treated gas to keep the carburetor clean. Removed carburetor and cleaned it, when I tore the carburetor apart I did not find anything noticeable wrong with it but cleaned it anyway. Noticed that the spring controlling the fuel on the carburetor was getting weak and replaced it. Kinda at a loss on what might be causing this. Does anybody have any ideas on might be causing this?

 

[jthibodeau89]

Check deck for bad bearings and belt drag.. All spindles and pulleys should turn freely with very little drag.

 

[redneck1952]

I replace all spindles last year, they spin free.

 

[redneck1952]

Check deck for bad bearings and belt drag.. All spindles and pulleys should turn freely with very little drag.

also replaced 2 pulleys on the mower deck

 

[jthibodeau89]

Belt routed correctly? Gear box turn free? Drive dhaft u joints free? From what you describe, something in deck drive is sucking HP.

 

[redneck1952]

you can't route the belt wrong and have it fit.
no gear box, direct drive off the engine.

 

[jthibodeau89]

Belt over or under one of the keeper pins at the pulleys?

When did issue start? If motor loses rpm when deck is engaged, sounds like a deck drive related issue. Electric pto clutch ok?

 

[redneck1952]

that would burn up the belts, they are in pulleys the way they should be. All belt placement and pulley condition was checked before posting on here.

 

[jthibodeau89]

I tried to help. Does not sound like a motor issue. I assume ir drives okay with blades turned off?

 

[John0829]

Check the color of the spark, is blue or yellow? I know you said you have replaced the spark plugs but that won't fix weak spark if that is what the problem is.

 

[redneck1952]

Your right about the spark. Will check it today. Got a new fuel filter to put on too. I had a new filter that was bad once before. I pretty much exhausted just about everything I could think of. Was hoping y’all could think of something I missed. I appreciate the help

 

[Bearsixty7]

Does it have an tachometer? RPM's should be about 3600 full throttle with blades off and 3500 with blades on.

It could be a bad coil.

 

[5030]

Could be an engine (underpowered) issue too. What motor and width of cutting deck? I can get my gas hog 23 horse Kowalski on my M60 Tank to work real hard in taller grass.

I remember reading somewhere that the Toro ZTR's were under powered.

 

[redneck1952]

Belt over or under one of the keeper pins at the pulleys?

When did issue start? If motor loses rpm when deck is engaged, sounds like a deck drive related issue. Electric pto clutch ok?

Have had it since the I started mowing this year. Unless there is something I don't know, every PTO either engages or not,

Does it have an tachometer? RPM's should be about 3600 full throttle with blades off and 3500 with blades on.

It could be a bad coil.

 

[redneck1952]

NO Tach, never have seen one on a mower.
Don't have tach to use on a mower either. Have to find one.

 

[Bearsixty7]

NO Tach, never have seen one on a mower.
Don't have tach to use on a mower either. Have to find one.

A lot of the newer ones have them, My Spartan's have them. I think Scags, JD and Gravely might as well, at least some models.

Small engine ones are fairly cheap, Amazon.com : small engine tachometer

Some are meant to be mounted on the machine and left and some are portable, hand held ones.

 

[redneck1952]

Was looking at them on the Amazon, very inexpensive. Going to order one.

 

[Fuddy1952]

Has it always been low on power, or just happened?

 

[Alan W.]

Does it have an tachometer? RPM's should be about 3600 full throttle with blades off and 3500 with blades on.

It could be a bad coil.

Thats what it was on my mower. Ran fine until the deck was engaged. Would not rev up.

 

[Midniteoyl]

Check the governor? I know you say that the gas is always treated, but have you drained and tried new? Looked to see if tank sump is clean? New fuel lines?

Gotta be fuel or spark related.. Double check all the fuel and swap the coil.