Oil for your Lawnmowers ?

Today I was giving my ride on mower a battery charge and grease up and found I was out of new fresh oil so coulndt do my annual oil change.

Last few years ive switched from SAE 30 to fully synthetic 5w30 and nothing has gone bang and I havent used any oil either.

So Ive gone from £5 for a litre of sae30 to £10 for halfords 4ltr instead.

As im using fully synthetic now will changing every 2 years be ok ?

Im running a 30 year old 12hp Briggs Stratton.

What do you guys use and when to do you change it ?

 

Don't ask

 

I assume your also using super unleaded?

 

I would use something a bit more generic than a modern synthetic 5-30 for an old engine like that. I do many miles on a motorbike, a far more stressed engine than your mower and just use standard 10-40 in summer and 15-50 in winter (I ride all year round and change oil every couple of months because of the high mileage). The BMW bike is pretty old technology, the BS mower is even more basic. I am surprised you haven't used oil to be honest, but after 30 years there will be a good coke layer built up to help seal the motor - modern, high detergent oils will break this down over a period of time and you will probably start to use oil and lose a bit of power.
Using a lower quality of oil in an older engine does no harm - classic cars can't use modern oils successfully, which is why Mr. Morris sells so much of their mineral oil for older car engines. It is expensive because of the economies of scale, you don't need to go to those lengths. Just buy a standard semi synthetic, or mineral oil if you can find it. Check the GL number specified (it might be on the engine plate, or it will be listed if you look up your model mower on the Briggs and Stratton lists, or in your manual if you still have it.

I would still change the oil regularly - oil and filters are cheap, engine rebuilds are expensive. My old bike, the one before this one, I sold it with 337,000 miles on it. I had only changed oil and filters regularly, I had never had the heads off, no need to - valve clearances and rocker end float, but just standard servicing. It was on all the original bearings too. A little mechanical sympathy goes a long way - when you start your mower, let it warm for 20 seconds before increasing the revs to start cutting. An engine wears the most while it is warming up, a motor that runs constantly and remains warm will last longer with fewer problems than one that only gets short runs.

The oil is more than coolant and lubricant, it also scavenges the wastes from combustion and collects all kinds of deposits, that is why it goes from clear brown to almost black over its life. All sorts of acids and other nasty products of combustion are collected in the oil. If you increase your service intervals your bearings and other moving parts are sitting in those nasty chemicals, and it is doing them no good. As you have said, a gallon of oil is £10 and will do you, even on that motor, 3 if not 4 oil changes. So you are quibbling about £3 worth of oil over two years - get a grip! Change your oil twice a season - it will cost you an extra fiver - how much is a bottom end rebuild for that motor? Only you would probably find it more economic to buy a new mower......for the sake of £10 worth of oil a year. Hmmm, I know where my money would go.

 

Against my better judgement, I'm going to answer this post. I will do so by taking the salient points which I have edited and quoted.

Generally speaking, the recommended oil for older B&S engines is a straight 30 oil. The big problem is, a lot of modern straight 30's are of worse quality than they used to be. Thats because modern regulations have forced manufacturers to remove or reduce various chemicals that are needed in old engines. B&S have recognised this, and newer (generally ohv engines) have been modified to accept newer type oils, including the 5W 50 mentioned. However, they still recommend SAE 30 as the primary oil choice. As regards detergent, all B&S motors built after WW2 use a high detergent oil. Therefore, assuming a correct type oil has been used, there will not be much of a problem with the oil washing away deposits. They should not be there. Generalising (again!) oil change intervals should be 3 months or 50 hours, whichever comes first. Given a 6 month lawn mowing season, that would be start of season, mid season, and end of season. Even if the engine is not run during winter! If the engine does have an oil filter, and many B&S dont, I personally would change it at every oil change. Alternating, ie oil+filter, then oil, then oil+filter is acceptable.

The "allowing the engine to warm up" is a good tip, and very true. Having said that, B&S engines are designed as constant rpm engines, and therefore designed to run hotter than say a car or bike engine that has a constantly changing engine speed. So 20 seconds is not really enough...

Edit: A correct oil for B&S, as well as a lot of other engines will be labelled "for off road (possibly race) use only" or "not for use in catalyser equipped vehicles."

 

lol... now that is one sweet V8 mower. For her I'd recommend Mobil 1.

I just use straight 30 in mine and it's always run great.

Your pic is great, reminds me of this old Youtube clip of a V8 chainsaw.

 

I wouldnt. Depending on the components used, Mobil 1 could wreck that engine very quickly..

 

@Sandy Ground, I've used mobil 1 in my big block Chevvy V8 hedge trimmer for the last 3 years and no problems whatsoever, except when an acorn somehow ended up in the supercharger.

 

@Mowerman , I'm surprised a Chevy has enough power for that!

 

@Sandy Ground - LOL

It has enough power for box hedge topiary. It falls over on privet.

For everything else I use my trusty Stihl modded with a Jag V12 and a stage 6 rally turbo to do the job. Runs like a dream on Castrol R.

 

Can we presume these V8 and V12 hedgetrimmers are not hand held
Still V8 and V12 thats some power .

 

They can be hand-held if you have 12 Shredded Wheat or Weetabix for breakfast

 

Well just did the change, 5w30 out , 10w40 in. Will see how we go with that. Will probably go backto the 5w30 in autumn due to the coller temps.
I seee briggs stratton recently changed their engine oil recommenadation to 5w30 synthetic all year round.

 

Those old Hayters just keep going. The old ones are far better than the newer ones.
I've a Hayter 48 Pro and it's been nothing but problems in the 5 years I've had it but reliable in the sence of the commercial work time scale if that makes sence. It's now only used on a few lawns now but it's in again for repair as the speed control died on me for the third time. When I first picked it up the the throttle cable screw was cross thread and it was back in within a week to have that fixed under warranty.
It's a shame they are owned by Toro now, have to say I will not be replacing it with another Hayter.
On the other hand my Etesia 46 Pro just keeps going and is now 10 years old and for a commercial mower that shows the quality of the product.
Better shoot off, I've a lawn to cut today or else I'll be in the dog house.