Why should I run my unit at full throttle?

[TRD]

It is necessary to run an air cooled engine at its highest rpm for the following few reasons:
A) The engine’s cooling and lubrication systems are designed to operate best when the throttle control is in the highest position. Running the engine at a lower speed will decrease the flow of cooling air and the volume of oil circulated. These two factors will shorten engine life.
B) The engine’s carburetor is adjusted so that the engine operates most cleanly and efficiently at full throttle. Operating outside or below the optimum speed range for the engine and carburetor produces less power.
C) Everything driven by the engine (eg. cutting blades) is/are designed to turn at the speed maintained by the engine’s governor when the throttle is at the highest position. Running the engine at a lower speed will result in lesser performance and excess vibration.
D) Models equipped with engines that have DC electric starters and battery systems and have engines that recharge the battery may result in poor battery recharge rate if the engine is not operated at full RPM. These engines have stators that produce recharge electrical current to the battery circuit only when properly tuned and operated at full RPM. Most frequently the report of poor battery recharging can be traced to customers that do not keep the throttle at full. On tractors, and other self-propeled units, the engine should be kept at full throttle whenever possible and the ground speed should be regulated by shifting into a lower gear or using the ground speed control. Do not use the engine throttle to regulate ground speed or the battery will not get sufficient electrical current to maintain charge.

 

[Spiffy]

Great advice! /forums/images/graemlins/cool.gif

I personally like half throttle for the first 10 maybe 30 seconds so lubrication gets circulated before the higher RPMs: may be counter-productive, but old habits die hard.

Also for me; I throttle back immediately before shut down [after a minute or better cool down at full throttle]; I think many engines are less likely to backfire at full throttle [potentially leaner], but throttled down has always treated me well. /forums/images/graemlins/smile.gif

For electric PTO clutches, I always throttle down when engaging under the assumtion the clutch will last longer due to decreased shock. Not sure just how much benifit does exist, but again old habits...

 

[MrWiggles2]

TRD- you are right. May I also mention, that proper break-in of rings, gears and valves seating properly occur when the engine is operating at full throttle. Also, running at less than full throttle not only decreases engine cooling, but significantly contributes to a hydrostatic transmission meltdown. Most hydros equipped with 2 qts of fluid need all the air they can get to keep temperatures down, especially those that are "non-serviceable".

 

[DmansPadge]

Sounds good to me. Like another poster mentioned... I always alway for warmup at idle. Was it's a operating temp (or close to it) run it full throttle!

 

[JTKub]

Tooling around the yard at less than full throttle on an unloaded machine is perfectly fine. You are not going to toast the hydro in this situation, nor overheat the engine. Putting the machine under load and/or mowing lawn will require full throttle. I cringe every time I see someone mowing at 1/2 to 3/4 throttle! You'd think they'd figure out why their lawn looks like crap. /forums/images/graemlins/confused.gif
G/luck
Joel

 

[MBDiagMan]

Yes, and some people think that they are saving gas by running at half throttle. They can't figure out that if they get done quicker they use less gas.

My Dad is 83 and can't push his mower to mow his city lot any more so I loaned him my old 30" Dixon. He insists on running the engine slow because he says he can't afford the gas. He has always had an obsession regarding gas mileage and gas prices.

Have a great day,
Doc