BobRip
Elite Member
When it starts to bog down if you choke it some and it revs back up it's a fuel starvation problem. If it's flooded and you choke it, it will stop quickly.
Different PT 425 problem
- Thread starter larrydman
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When it starts to bog down if you choke it some and it revs back up it's a fuel starvation problem. If it's flooded and you choke it, it will stop quickly.
DCWhitley
Member
Is it true you should always run the 425 WOT? I'm sure when I picked up my PT I was told you only had to run WOT when mowing or using the snow blower. Other times I run it about 1/2 open, then increase the throttle as needed. Anyone else heard different?
Marks481
Platinum Member
- Joined
- May 29, 2005
- Messages
- 978
- Tractor
- Power Trac 422 (2005)
The Robin engine owners manual states 'Whenever high speed operation is
not required, slow the engine down (idle) by moving the speed control lever to save fuel and extend engine life."
I operate mine like yours; WOT for mowing, idle for everything else and throttle up a little when it seems to start to bog down.
I think PT recommends the high speeds to ensure maximum cooling air flow through the engine; maybe it is in the PT manual.
not required, slow the engine down (idle) by moving the speed control lever to save fuel and extend engine life."
I operate mine like yours; WOT for mowing, idle for everything else and throttle up a little when it seems to start to bog down.
I think PT recommends the high speeds to ensure maximum cooling air flow through the engine; maybe it is in the PT manual.
BobRip
Elite Member
I also do this. If I need a lot of torque I go full throttle, but for example if you are driving down hill just carrying dirt, no way do you need full throttle.
MossRoad
Super Moderator
- Joined
- Aug 31, 2001
- Messages
- 58,074
- Location
- South Bend, Indiana (near)
- Tractor
- Power Trac PT425 2001 Model Year
I pretty much run my 2001 model year PT425 with the Kohler engine wide open all the time. Mowing, loader work, forks, snow plowing, etc... When hauling heavy loads up and down hills, I have better control and more braking power.
My late 70's International 2500B (50 PTO HP, big gas engine, hydro tranny, cab, 8000 pound tractor) operator's manual said to run it at the PTO speed on the tach all the time to provide proper pressures and safe operation.
I drove hydraulic articulated aircraft moving equipment for a living for 6 years back in the 70's and 80's. They were wheelhorse tractors with no front axle, a heavy steel fork articulated off the back. The seat was on the hood and you drove with the steering wheel between your legs. Attached is some pictures of them. We always ran them at full throttle, too.
This is one of the reasons small hydro tractors use so much more fuel than small gear tractors. You need the full engine RPMs to keep the pumps at proper operating pressures. Larger hydro machines will throttle up and down the engine as it senses the need for more pressures, but the small machines do not have these features and need to run all out most of the time.
My late 70's International 2500B (50 PTO HP, big gas engine, hydro tranny, cab, 8000 pound tractor) operator's manual said to run it at the PTO speed on the tach all the time to provide proper pressures and safe operation.
I drove hydraulic articulated aircraft moving equipment for a living for 6 years back in the 70's and 80's. They were wheelhorse tractors with no front axle, a heavy steel fork articulated off the back. The seat was on the hood and you drove with the steering wheel between your legs. Attached is some pictures of them. We always ran them at full throttle, too.
This is one of the reasons small hydro tractors use so much more fuel than small gear tractors. You need the full engine RPMs to keep the pumps at proper operating pressures. Larger hydro machines will throttle up and down the engine as it senses the need for more pressures, but the small machines do not have these features and need to run all out most of the time.
Attachments
cqaigy2
Super Member
Pretty much the same.
Red Zebra
Silver Member
Those cantelevered front-ends turly look odd.
On the subject of throttle position: WOT when using PTO circuit (mowing, auger, mixer) and about 3/4 or more as needed when using non-PTO attachments.
I had a football coach that used to say, "Run wide-open all the time, that way if you make a mistake, you make it at full speed!"
In PT terms, that means if something is going to break or go wrong... it'll be something to remember! GO BIG or don't go!
SnowRidge
Elite Member
The control labeled "throttle" isn't really a throttle. It is a RPM control hooked to the governor. The governor controls the real throttle (the carburetor butterfly).
There is nothing wrong with running at reduced throttle with non-PTO implements during low load conditions, except maximum ground speed will be lower and lift capacity will be reduced. However, these engines are designed to run at maximum speed, with the governor adjusting the real throttle according to the load. Kohler, for one, even calls the two throttle extremes low idle and high idle. Running at other than high idle will result in less cooling air and reduced oil flow. Running at high idle, while taking it easy with the task at hand, should result in better lubrication and cooling than throttling back.
With some PTs, there is another issue to consider. That is the PT designed and built muffler. I know mine was defective, either through design or manufacture, and choked off the engine badly. When I junked it and installed a Kohler muffler, fuel consumption dropped dramatically and run-on disappeared.
It may be that engines that still have a PT built muffler will benefit from running at a lower throttle setting, if the muffler can't flow enough exhaust at the full throttle setting.
Anyone running gas with ethanol in it should also be aware that the ethanol raises exhaust temperatures in these engines. I opened a thread on the subject here.
It seems possible that the combination of a defective muffler and ethanol in the fuel raises the operating temperature of these machines to the point that running them at their full rated output will likely result in early failures, along with very high fuel consumption, in which case, throttling back seems like a wise thing to do.
Each and every owner needs to evaluate their own unique situation and fuel, modify, and or/operate their machine in a manner suitable to the circumstances at hand. Unfortunately, there are no magic answers.
There is nothing wrong with running at reduced throttle with non-PTO implements during low load conditions, except maximum ground speed will be lower and lift capacity will be reduced. However, these engines are designed to run at maximum speed, with the governor adjusting the real throttle according to the load. Kohler, for one, even calls the two throttle extremes low idle and high idle. Running at other than high idle will result in less cooling air and reduced oil flow. Running at high idle, while taking it easy with the task at hand, should result in better lubrication and cooling than throttling back.
With some PTs, there is another issue to consider. That is the PT designed and built muffler. I know mine was defective, either through design or manufacture, and choked off the engine badly. When I junked it and installed a Kohler muffler, fuel consumption dropped dramatically and run-on disappeared.
It may be that engines that still have a PT built muffler will benefit from running at a lower throttle setting, if the muffler can't flow enough exhaust at the full throttle setting.
Anyone running gas with ethanol in it should also be aware that the ethanol raises exhaust temperatures in these engines. I opened a thread on the subject here.
It seems possible that the combination of a defective muffler and ethanol in the fuel raises the operating temperature of these machines to the point that running them at their full rated output will likely result in early failures, along with very high fuel consumption, in which case, throttling back seems like a wise thing to do.
Each and every owner needs to evaluate their own unique situation and fuel, modify, and or/operate their machine in a manner suitable to the circumstances at hand. Unfortunately, there are no magic answers.
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SCOTCHERS
Bronze Member
Larry,
I believe and hope it's as easy a problem as I encountered in 2004 after only 30 hours of my brand new PT. I discovered at the bottom of my gas tank some litter had blocked the gas from getting into the lines and periodically I'd hit the right bump or ditch while mowing and it' would clog. I changed my filter and drained my gas tank and blew out my fuel line and never had a problem since.
We'll pray that works for you!!! I know how discouraged I was after only a few hours. I now have 575 hours and love this thing almost like my wife and kids.
Good luck man
John in Maryland
I believe and hope it's as easy a problem as I encountered in 2004 after only 30 hours of my brand new PT. I discovered at the bottom of my gas tank some litter had blocked the gas from getting into the lines and periodically I'd hit the right bump or ditch while mowing and it' would clog. I changed my filter and drained my gas tank and blew out my fuel line and never had a problem since.
We'll pray that works for you!!! I know how discouraged I was after only a few hours. I now have 575 hours and love this thing almost like my wife and kids.
Good luck man
John in Maryland