I bought my mower with 20 hours last year. Previous owner said that he changed the oil once. I used it all last year with no problem.
This year I got up to 55 hrs and I figured I would change oil and airfilter , so I bought a tune up kit that had the Toro SAE 10w30 oil in it.
Since the oil change it has been burning oil 3-5 minutes into mowing. Sometimes its a big cloud of blueish smoke. Before the oil change it would occasionally have blue smoke at start up but never while running.
I was thinking it might be overheating but cooling shrouds are clean, nothing plugged.
I’m thinking maybe the oil is too thin?!
Any pointers would be appreciated. Cant believe at 60 hours I would have issues with piston rings or valve seals.
Please post the model and serial numbers of both the unit (under the seat) and engine. That way we will know exactly what you have as there are about 10 different setups.
Make sure you haven't overfilled it, 10w30 should be correct weight, when overfilled it will blow white and blue smoke, give us the engine numbers like Rivits ask and we can tell you how much oil and what weight it calls for.
#4
Valddlav
Thanks guys! I put in about 1 and a quarter pint, the diamond area on the dip stick is little above the middle, closer to full.
Model: 74710
Serial: 316001716
Couple of things don’t make sense to me, but they could be true. First, according to your serial number you have a 2016 unit, with supposedly only 20 hours on it???? Second, did the owner tell you the last time it was used, not just run? Third, do the owner tell you when he changed oil? Fourth, it started blowing smoke after you changed oil, When it starts blowing smoke, is it continuously or sporadic? When it blows smoke do you feel it loosing a little power? Sorry to ask all these questions, but my brain says something doesn’t add up. Here a service manual for the engine, but don’t start doing anything until you answer my questions. Just don’t want you to throw money at it until we have an idea what’s going on. https://www.toro.com/getpub/70680
That may be the route to go, but need more info before suggesting how to proceed.
#11
Valddlav
Thanks for all the questions guys!
When I bought in April of 2019 the previous owner told me that he bought it in 2017 as a leftover model and that he did not use it all in 2017 and used it for 20 hours in 2018. Did not work for him as he has steep hills on his property and bought a diesel lawn tractor instead.
I was thinking at the time that he could be lying to me and that he used it more than 20 hours and just installed the hour meter later, but it indeed looked like brand new, so I figured the 20 hrs on the meter was accurate.
He told me that he chainged the oil in it in 2018 after 5 hours. I did not ask what kind of oil did he used.
So as I said last year I used it with no problem whatsoever, other than blue smoke sometimes at cold start. Saw it in the manual that I could go up to a 100hrs to change the oil, but I figured once per season should better and since I did not change it last year, I ordered the tune up kit.
Last time I used it a few days ago, it smoked at start up and after about 3-5 minutes. At the end of the rows when I was turning around a big cloud of blue smoke hit me in the face, I was probbably dragging that behind me and not realziing it until I turned back into it. I disengaged the blade and had it on idle for 30 sec as I was thinking maybe it was overheating. I sensed no power loss though. After idle for 30sec I would give it full throttle and engage the blades and start mowing again.
About 3-5 minutes later the same thing would happen. Then I disengaged the blades, set it to idle and got up the mower to see what it looks like. Do I have constant smoke coming out. Saw nothing at idle, gave it a blip of full throttle and big blast of smoke would come out. Then I gave it full throuttle and again a blast of smoke would come out but when I left a throttle on the engine was running at max rpm and there was no smoke. I though that was weird but I was thinking there was no load on the engine.
I did not think that I had to much oil based on the dipstick but the service manual you linked it shows oil capacity of 1.05L, I put in 1.4L so maybe I indeed have too much. I also thought maybe the previous guy had regular SAE 30 in there and the SAE 10w30 I put in there is thinner, so maybe I can just chnage the oil to SAE 30 and put less in there to start with.
Anyways I bought a compression test kit at harbor freights, I got 90psi cold and 95psi with oil. Is that normal for this type of engine?
www.toro.com
Appears to use a Toro Branded engine... 452cc, ENGINE-1P92F-1 
