Lawnboy oil change

Status
Not open for further replies.
G

GMFan

Joined
Dec 26, 2007
Messages
2,534
Location
NC
I have a lawnboy self propelled lawn mower and I'm going to give it a tuneup tomorrow. In my garage I have a little less than half a quart Pennzoil 10w-40 and a little less than half a quart Mobil Clean 5000 10w-40. The lawn mower manual says a straight 30w or a 10w-30.

Can I use the 10w-40? It's a few years old and I'd like to get rid of it. I figure a lawnmower isn't very picky, especially when I've heard of people never giving them oil changes. I may also have to mix some Mobil Clean 5000 in since I may not have enough of the Pennzoil. I assume this should be ok as well.

Thanks.
 
UOA the oil in there before deciding whether or not you need the 10W-40, maybe you can order some Amsoil SSO 0W-30 to help it with cold flow and extend your intervals.

I honestly don't think the lawn mower will know the difference, to be honest. You could put anything from the cheapest straight 30 non-detergent oil in there to Lubro-Moly 10W-60 synthetic and it probably would not have any change in performance or reliability.

There's a test for BITOG, get two identical 3.5 horsepower, blueprinted, governed stationary engines, tune them up to factory spec and put them running at a fixed load for a set number of hours on a variety of motor oils and then UOA them as a one versus the other in fixed conditions on the same fuel, same ambient temperatures, same load, et cetera.

Completely pointless but still more scientific than a lot of the stuff said on here.
 
10w40 will work just fine. I put 15w40 in mine. Straight 30w might be the best but I would think 10w40 would be better than something like 5w30. I have ran 10w30(a bit of smokage at startup) also. Pour in what you got and tell the new owner she needs some 30w after about 10hrs. Most people don't change the oil in their mowers and they last forever!
 
Ok, well I did the tuneup.

I think the oil hadn't been changed in two seasons. It was pretty mucky looking, and had some whitish swirls in it toward the end of the draining. When I shined light in it I did see some metal sparkling.

I put in the Pennzoil 10w40 and had to add a little Mobil Clean 5000 10w40 because I ran out of the Pennzoil and want to use up the old motor oil I have lying around.

BTW, this is a 1997 Lawn-boy Medallion (made by Toro) 6H.P 4 cycle overhead valve commercial grade engine.

Money is a little tight as of yet. I usually mow every 7 to 10 days in the summer and it takes about 45 minutes to an hour to mow the lawn. Anybody have an idea how long this engine will last? It hasn't been burning any oil.

Thanks.
 
Will do. Just think I totally forgot about doing a tuneup last time.

Before this mower, we had a Toro last us 17 years.

Briggs & Stratton makes a good engine. I used WD-40 on all the moving parts and cleaned it up nice. It now has a new spark plug, cleaned/oiled air filter and new oil.
wink.gif
 
Last edited:
Originally Posted By: MGregoir
UOA the oil in there before deciding whether or not you need the 10W-40, ............


UOA the oil in a lawn mower engine?

That is like sending a cat to a vet or a BIC lighter in for repair, worthless!
 
Originally Posted By: Hootbro
Originally Posted By: MGregoir
UOA the oil in there before deciding whether or not you need the 10W-40, ............


UOA the oil in a lawn mower engine?

That is like sending a cat to a vet or a BIC lighter in for repair, worthless!


My thoughts exactly. Why do a $2o-25 UOA on 20oz of oil. They will run forever if you do any kind of maintenance on them.
 
Me thinks MGregoir was joking...

Just make sure theres fairly clean oil in the mower and it will be ok.
As I understand it, in mowers without oil filters the detergent is not necessary but not damaging either. It's most often a splash lubrication engine so the oil must be able to splash a bit so avoid pure grease. The engine oil is very hot so avoid very thin stuff too. But any regular auto oil will do. If it smokes, use something thicker.
Change oil often, maybe at 20 hrs or so.
 
Last edited:
GMFan, what kind of weather you having in NY. I'm still using my snowblower.
grin2.gif


Oh, and the 10W40 works just fine in those old mowers. It will probably out last you.
 
Well, I started it up to make sure all was well and the engine started after 4 or 5 pulls. It was semi-cold outside (40 degree F) but there was no smoking or anything. I let it run for about 3 minutes. I then carefully checked the oil and it was already steaming hot. Those engines really take on the heat.

Johnny, weather has been thawing out slowly here. The ground has softened. Not much snow in the past few weeks. Our snowblower is another story. It is a 35-year old or so Simplicity Snow-Away by Briggs and Stratton. It sees regular oil changes and we recently had the pull starter rebuilt. Still runs, but it clanks when it runs. Maybe a piston slap?
grin2.gif
 
Congrats on maintaing your mower so well. I warm up my Honda for 1 minute. Think I'll go to 2 minutes. I run Mobil 1 10w-30EP. Change in july and nov.
 
You can be a big spender and change the oil twice a year. Or if in doubt change it an extra time. What's it take a quart or so.

About warm ups. I'm not sure. We have some Honda engines on water pumps at a gold mine. As an experiment we set two each at 1 minute, 2 minutes, and no warm up. After 3 years of hard use and partial tear downs there was no difference in the engines. These engines all used Chevron Delo 400 30w engine oil. A warm up makes you feel better but I'm not sure these little aluminum engines need it. I could be wrong.
 
It hurts me to see "changing oil in a Lawn Boy".......I am going out to the garage to hug my two cycle aluminum deck antique......
 
Long live the 2-stroke! I just bought a brand new Lawn boy 2-stroke last week. Found it at a small engine shop, last one left. The guy told me that when lawn boy announced they were discontinuing the 2-cyle, this shop ordered a whole bunch of them. I got the last one, model 10550. Aluminum deck, pull start, self propel. Exactly what I wanted!!!
 
Thanks for the comment on warm ups. I'm going 1.5-2.0 minutes and call it good.
 
Originally Posted By: BarkerMan
About warm ups. I'm not sure. . . . As an experiment we set two each at 1 minute, 2 minutes, and no warm up. After 3 years of hard use and partial tear downs there was no difference in the engines. These engines all used Chevron Delo 400 30w engine oil. A warm up makes you feel better but I'm not sure these little aluminum engines need it. I could be wrong.

Warm-up is generally unnecessary in any engine using the oil specified for it. This is particularly true of small air cooled lawn-mower type engines because they have a splash oiling system, not pumped. One or two revolutions, regardless of oil temperature, and everything that needs to be lubed is being lubed. This is why it's foolish to run multi-grade oils in lawn-mower type engines. A mono-grade oil is a more robust oil than a multi-grade, putting more oil between the moving parts. Then too, multi-grade oils shear down, then slip past the rings and carbon up the combustion chamber (much more than a mono-grade oil).

My 3-hp Briggs & Stratton lawnmower engine is over 35 years old. I bought the lawnmower used in 1978 (I think it was about five years old at the time) and had to replace the deck which rotted out about 10 years ago (picked up a throw-away from a lawnmower shop for a few dollars). Engine's still going strong although it's getting a little harder to start. Usta run it on 20W-50 because that's what I usta run in my car all the time. Then switched to mono-grade SAE-30 about 10 years ago like all the small engine owner's manuals say to do. My mower runs about 30 minutes once a week, summer and winter. If it ever starts to smoke, I'll start running it on SAE-40 mono-grade.
 
Well, came back to update.

Since the oil change I have mowed the lawn 3 or 4 times. It has started to consume a little bit of the oil.

I only have 5w30 in my house now and that is for the cars. Will it hurt if I eventually get around to picking up a quart of 30W and dump that in with the 10w40?

I'm assuming the 10w40 has become heavily sheared (inevitable in these engines) and is being burned.
 
Originally Posted By: GMFan
Will it hurt if I eventually get around to picking up a quart of 30W and dump that in with the 10w40?

No.

Regards, Gary in Sandy Eggo
 
Status
Not open for further replies.

Similar threads

M
Snapper mower
Replies
17
Views
1K
nwjones18
O
Need opinions on a new riding lawn mower
2 3 4
Replies
65
Views
2K
Cujet
W
Oil for Kaw 651
Replies
9
Views
1K
MParr
svtrit
HM oil in new lawn mower?
Replies
7
Views
2K
jeepman3071
E
Friend needs a NON-self propelled lawnmower
2
Replies
27
Views
2K
PontiacHO
Back
Top