What weight oils for a mower?

[Lizzy Koltai]

Hi,

What weight oils are recommended for the gear box and bar of a McCormmick #7 mower?

Thanks,
Lizzy

[Jay]

Lynn Miller’s Mower book recommends 10-30 I believe, and that’s what I use. Often any old oil left in a machine will be thick and so the new oil may leak more. New seals at the lower end of the pitman shaft would be in order. Jay

[Donn Hewes]

In the gear box I use motor oil as Jay described. It is easy to way over fill them. The gear boxes rely on the spinning gears to send it every where. 4″ in the bottom of the gear box will cover half of the lowest gear. That will be more than enough. The cutter bar is another matter. Many different opinions about how and when to oil that. While I will use a great deal of oil in the shop just to see how loose and free the knife is, I usually rely on the moisture in the grass to lubricate the cutting. This might vary in different regions depending on how much sand is in the soil and other local factors. Regardless of how or when you oil the knife there other places to oil or grease. In the dolly wheels there are two grease fittings. These could be greased twice a year for average use. I use an oil can on the lifting parts and hing parts occasionally. By far the most important point to oil on a mower (and it should be oiled every time you go out) is the ball joint where the knife attaches to the pitman stick. Based on many broken mowers and parts sold these are the hardest working parts. They are designed to be held tight enough for no play or slop and still retain the ability to shift slightly with every stroke. you will find the ball on new knifes worn away by a tight pitman clamp without oil.

[Jay]

I echo Donn’s comment about making sure the ball joint connection with the pitman stick is oiled REGULARLY. I make sure I have an oil can with me whenever mowing and put a few drops on the ball every time around a large field. This is a classic example of regular maintenance being way better than dumping alot on just once in a while. (a quart plastic hypoid gear oil container makes a nicely shaped oil can and fits into the hole on the mower well). If the ball feels warm to the touch, it’s not getting near enough oil and will wear out both the ball and the 2 arms that surround it from the pitman stick. Jay

[Lizzy Koltai]

What oil do you fill your oil can with? 75W-90? 80W-90? Anything labeled “gear oil”?

Lizzy

[LongViewFarm]

I used mineral oil because that’s what I had. From Donn I heard “Lots of oil in the shop, little or none when cutting.” Believing that the moisture in the plants was enough and less oil reduced accumulation of chaff ( I think)

[Jay]

I like Donn use none on the bar. Keeping the ball on the end of the knife oiled is very important. I use regular motor oil in my oil can. I suggested using a hypoid gear oil bottle for an oil can as it fits in the mower well. Fill with regular motor oil or what ever you have available. I have on occasion used used motor oil when out of new oil.
Jay

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