Reduce governor speed for engine life?

[Alpha8D 0]

I set the governor on my 1965 10hp Landlord 101 Briggs at 3400rpm rather than 3600 rpm because I want it to last as long as possible. There’s nothing wrong with the engine, I just want it to last and at 3400 it seems to cut grass OK and has plenty of pulling power. I recall from somewhere hearing stress and wear and tear on reciprocating parts is directly proportional to the square of the RPM. Am I kidding myself or will it really last longer?

[HubbardRA 19]

In my opinion, the answer is yes, on the older engines. This is providing the engine is not being loaded extremely heavily at that rpm. Higher rpm gives more power and more engine cooling. Being a mechanical engineer, I am well aware that high rpm without substantial load on an engine can cause excessive vibration in the engine which will reduce engine life. If the engine is under heavy load, then the engine should be run at the prescribed rpm. I set my governors for somewhere between 3600 and 4000 on my tractors. I control the engine speed with the throttle and hardly ever run them at WOT unless I am mowing really heavy grass, or pulling a heavy trailer in higher gears. Most of the newer aluminum engines that are OHV with oil pumps, need to be run at WOT to cool properly and get sufficient oil flow. Your landlord should do fine at lower rpms, as long as you are not lugging the engine at those rpms. Anytime you repetitively hear the governor opening up, you should go to WOT.

[Alpha8D 0]

Thanks Rod, Was hoping you'd respond, I value your opinion. I am hard of hearing and wear hearing protection so the engine sounds quieter than it is and if I take them off I'm occasionally surprised to be close to WOT. So I'll leave my gov. set at 3400. I do not usially run at even that but at whatever lowest speed cuts the grass clean and doesn't lug. Now when I hear the gov. kick in I'll boost throttle a little. When I'm going downhill like down my steep driveway the governor hunts. Is this normal? Jim

[BLT 717]

You're seeing that already in walk behind lawnmowers. They advertise 6.5 HP mowers because that is what they can develop. However a lot of them are cut back to 3000 RPM or less. That is for less blade tip speed, overall noise, emissions and engine life.

[orangeone 0]

I agree with Rod H. Keep them Running at or near 3550-3600 to keep them cool .Change the oilat reg times I go at 25 hrs. And keep the filters clean. Lug it if you have to but keep it short.

[HubbardRA 19]

Hunting could be a governor problem, maybe wrong governor spring. Most of the hunting that I have had on my machines has been due to incorrect carb adjustment. If the carb continues to hunt on a regular basis, it will eventually wear the throttle shaft and it's bore in the carb. Try adjusting the carb a little and see if the hunting stops.

[powerking_one 0]

Roger, Changing the oil @ 25 hours on a splash lubricated engine is a sure recipe for short engine life. If one is serious about extending an engine's life, change intervals of 10-15 hours is more like it. Even Dutch would agree (RIP). Case in point, my dad's Broadmoor repowered in 1975 with an aluminum bore 10hp Briggs 2517xx engine had in excess of 1500 hours on it before selling; it burned zero oil (with the above change intervals). Tom (PK)