Lipstick on a...mower? (Long)

[tony1679]

I am at a loss. I inherited an '09 Yard-Man riding mower (non-zero turn) in 2011 with a B&S 12.5hp single cylinder. I am almost at my wit's end. This mower has major issues doing its job - cutting grass. I always have to run at ~90-95% throttle. Out of 6 "speeds" (6 being fast) I have to drive at 3 or less, which is literally a walking pace. While doing that, I can only utilize 50-60% of my deck width (meaning I have to overlap like crazy to prevent it from choking itself). All of this, and it still struggles to cut grass ~6" high (I cut at a 3" setting.)

I maintain this mower to the best of my ability. Oil changes every year (~60 hours, I use synthetic 5W-30), air filter yearly (I live in a sometimes dusty area), new plug yearly, fuel filter every other year, new blades yearly, belts as needed (basically yearly). Always E-0 gasoline. I even took this mower to a pro earlier this year to do "anything beneficial/tune-up" and told him cost was no object (he is honest). He did a valve adjustment, and chiseled/cleaned the underside of the deck. He said everything else looked not good, but great.

It takes me 3-4 hours to cut a lot that is .91 acres, smaller when you subtract a 2,000 sq. ft. house and a 4-car detached garage. My neighbors do their 1.5 acre lot in 1 hour or less with their JD zero-turn (yes, I am jealous). I know, why not just go buy a zero-turn? I don't have $4-5k laying around, or I would.

Is there anything I can do to improve performance? Anything maintenance-wise I am forgetting? Basically is there anything to help out my under-powered pos?

Or do I need to go buy some lipstick? (Will that add hp?

)

 

[Lubener]

Since it sounds like the mower was gone over, I would check compression. You may have a tired engine. 3-4 hours, I could do your lot quicker with my 22 inch cut Craftsman.

 

[tony1679]

Originally Posted By: Lubener
Since it sounds like the mower was gone over, I would check compression. You may have a tired engine. 3-4 hours, I could do your lot quicker with my 22 inch cut Craftsman.
In the mower's defense, my lot does have a lot of obstacles and fence lines. But I am really thinking it isn't really the motor that is the cause of my problems. I am leaning toward the deck. But what could possibly cause the deck to have issues?

 

[Nukeman7]

Originally Posted By: tony1679
Originally Posted By: Lubener
Since it sounds like the mower was gone over, I would check compression. You may have a tired engine. 3-4 hours, I could do your lot quicker with my 22 inch cut Craftsman.
In the mower's defense, my lot does have a lot of obstacles and fence lines. But I am really thinking it isn't really the motor that is the cause of my problems. I am leaning toward the deck. But what could possibly cause the deck to have issues?


It sounds like there is a significant amount of belt slippage on the drive mechanism for the cutting deck blades. I suspect that you are not getting the proper blade tip speed which, in turn, requires you to mow slowly and repeatedly over the same areas. Might be a weak tensioner pulley or binding or misalignment of the pulleys.

 

[Turk]

Since you're almost at your wit's end.....

Adjust whatever governor or modify whatever throttle stop to increase it's RPMs.
Not by a lot, duh, just some. Give it a shot if you like and report back.

 

[Pop_Rivit]

You have a very small engine in a fairly poor quality lawn tractor. To top it off you're talking about cutting 6 inch tall grass down to 3 inches, which is a lot of work for any small mower-it probably has around a 42 inch deck, correct? A little 12 horse engine just can't handle it, especially if it's one of the many engines one which Briggs overstated the horsepower.

Assuming your "pro" knows what he's doing he should have checked the bearings and belt on the deck when you gave him carte blanche to go over the mower. According to him everything looked "not good, but great".

Mow more frequently so you're only taking an inch or so off or set the deck for a higher cut. I personally don't like to mow my yard any shorter than 4 inches, and try not to let it get above 5 inches or so. Keep your blade sharp-you don't need to replace it every year but you do need to sharpen it frequently.

Other than that you could look at repowering the tractor, but quite frankly it's not one that's worth repowering.

 

[TFB1]

If belts are slipping it will no doubt maintain approx normal engine speed but blades will be slowing, with as much throttle as you are using belts would be burned up in just a few cuttings...

If motor bogs down you have a power problem, or maybe binding in deck...

Assuming a healthy engine there could be a carburetor issue, or intake from carb to block/head has a vacuum leak... If that's the case using partial choke almost always improves performance...

 

[eljefino]

Riding mowers have better (faster) blade speeds than walk behinds as the safety aspect (respecting your feet) is not so relevant. I'd look at a different blade design. You may have a mulching blade on there or at least one incompatible with the deck, or one beat to heck. Get a new, "normal" blade for side discharge.

Mulching blades make it happen by flinging the old grass upwards so they can chop it again and again, sapping energy. Nuts to that!

 

[zrxkawboy]

Assuming the belts are not slipping for some reason, I think Pop's post is right on.

 

[Eddie]

Trying to cut 6 inch grass to 3 inches with a 12 HP anything is Toooo much. My 20 HP twin would grunt at that load. As suggest mow twice as often or by a real tractor with 24HP +. JMO. Ed

 

[brandini]

Isn't rule of thumb only cut 1/3 of the grass' length in one go?

To start, I'd be cutting more often if I were you.

 

[Oldmoparguy1]

Quote:
I am at a loss. I inherited an '09 Yard-Man riding mower (non-zero turn) in 2011 with a B&S 12.5hp single cylinder. I am almost at my wit's end. This mower has major issues doing its job - cutting grass. I always have to run at ~90-95% throttle. Out of 6 "speeds" (6 being fast) I have to drive at 3 or less, which is literally a walking pace. While doing that, I can only utilize 50-60% of my deck width (meaning I have to overlap like crazy to prevent it from choking itself). All of this, and it still struggles to cut grass ~6" high (I cut at a 3" setting.) mad


Which model is it? is it a rear engine type, or front engine type. If it's a rear engine, then it will have a friction drive which is probably worn out. Need to know in order to help you. Your engine is a 28 cu. in. flat head. Should be enough power to run a 38" 2 blade deck. Mower engines are made to run wide open all the time. I usually run mine 90% unless I have the bagger on. Then it's full throttle. Also, why wait til the grass is so high? You will get a cleaner cut when you only do 1" or so at a time.

 

[bubbatime]

Originally Posted By: Pop_Rivit
You have a very small engine in a fairly poor quality lawn tractor.


This about sums it up. You are asking too much of your current mower. And honestly, your mower is worth $300-$400 on the used market. Sell it on Craiglist and buy a nice used replacement with a bigger engine and bigger deck in the $500 to whatever you can afford range.

 

[IndyIan]

Check the timing in addition to the rpms? I have an old 42" 16hp OHV single briggs with the hydrostat trans(which eats some hp) and it won't bog for anything so far. It will start leaving grass uncut if its too heavy, but it takes 9-12" grass to make it open up the governor and start to work hard.
It does have normal blades for side discharge which may help.

 

[Rand]

if you want to go the disposable route sears frequently has junker tinfoil lawn mower tractors for ~~1000$ with 20hp 2cyl briggs if you watch for deals

It will last about 5 years before it falls apart or gets bent up.


What kind of new blades do you buy for your current one?
is it mulching or side discharge?

 

[andyd]

Did you put the blades on upside down? That will really make mowing hard. AMHIK

 

[JTK]

3-4hrs to cut an acre? Good grief! I could do that quicker with a 21" push mower. This isn't an old machine. It's got a ~12hp OHV engine on it. The engine isn't the problem. That's plenty of HP for a tiny riding mower with a twin blade 42" deck.

Like said, it sounds like the issue is you're letting the grass get too high and trying to cut too low.

Grass mowing issues are generally due to three things. Trying to cut too much, too fast or too wet.

 

[tony1679]

Thanks for all the replies. A few thoughts:
Originally Posted By: Nukeman7
It sounds like there is a significant amount of belt slippage on the drive mechanism for the cutting deck blades. I suspect that you are not getting the proper blade tip speed which, in turn, requires you to mow slowly and repeatedly over the same areas. Might be a weak tensioner pulley or binding or misalignment of the pulleys.
This sounds like good advice for my particular condition. Thanks.
Originally Posted By: Pop_Rivit
To top it off you're talking about cutting 6 inch tall grass down to 3 inches, which is a lot of work for any small mower... Mow more frequently...
I was erring to the high side at 6" I mow every 2 weeks. It's not TOO tall. 2 weeks is more frequent than most of my neighbors mow. They don't have any issues. Yet my mower struggles.
Originally Posted By: Eddie
Trying to cut 6 inch grass to 3 inches with a 12 HP anything is Toooo much. My 20 HP twin would grunt at that load. As suggest mow twice as often or by a real tractor with 24HP +. JMO. Ed
There was one instance two years ago where my grass got about 10-12" tall. The weeds in some places were 2.5 FEET tall. I was away for over a month... My neighbor just bought his JD 22hp twin zero-turn and desperately begged me to let him cut my lawn (he wanted to see what it was made of

) He mowed my whole lot in 42 minutes. Without even a thought of struggling.

I understand, comparing our two mowers is like an apple and an orange. But 3" is not too much, and should not be bringing my blades to a halt.
Originally Posted By: Oldmoparguy1
Also, why wait til the grass is so high?
It's a front engine. I mow every 2 weeks. I don't think that is too long. It's hard to find time to do it more frequently. Mowing during the week isn't in the cards. And mowing EVERY weekend is just idiotic.

 

[ragtoplvr]

when you say 95 percent throttle do you mean the hand control. You should always run that engine at the highest setting before the choke starts to move. The throttle is not like a car throttle. It has a governor. The "throttle" sets the RPM. The governor controls the amount of throttle opening to maintain RPM

BTW, I had a 42 inch Dixon with 11 briggs that i used for 30 years. It never needed more power, even after 2 weeks of no cutting.

Rod

 

[Pop_Rivit]

Originally Posted By: tony1679
I was erring to the high side at 6" I mow every 2 weeks. It's not TOO tall. 2 weeks is more frequent than most of my neighbors mow. They don't have any issues. Yet my mower struggles.

Do any of them try to do it with an old, used, small, hand-me-down Yard Man mower? It sounds like they have mowers that are far superior to your old disposable Yard Man. Do you suppose the power and quality of the mower makes any difference?
Originally Posted By: tony1679

My neighbor just bought his JD 22hp twin zero-turn and desperately begged me to let him cut my lawn (he wanted to see what it was made of

) He mowed my whole lot in 42 minutes. Without even a thought of struggling.


You just reaffirmed my previous comment. Yet you're trying to insist that your tiny little mower should be capable of doing what your neighbors' mowers can do, when they have almost double the horsepower and far better quality machines.
Originally Posted By: tony1679
Mowing during the week isn't in the cards. And mowing EVERY weekend is just idiotic.


Yet I mow at least once a week. It takes me an hour to mow the three acres that I finish mow. It takes you three times as much time to mow less than 1/3 of what I mow with your Yard Man and your two week cutting schedule. Over a two week period I spend 2 hours covering 6 acres (3 acres twice), and you spend 3-4 hours covering less than an acre once. At the end of two weeks I'm at least an hour ahead of you in time.

Personally, I think spending that much time mowing that small amount of yard is just idiotic, even if it is just once every two weeks. Especially when you spend that amount of time fighting with a disposable, undersized lawn tractor that can't handle what you need it to do.