Repair lawn mower motor or replace mower?

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May 30, 2011
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Toronto ON, Canada
Here is my dilemma. I bought a mower in 2011 that is pretty much like this one for this year (specs and all) here:
http://www.sears.ca/en/mowers/21-3-in-1-push-lawn-mower-148376_I.html?cgid=wh3_outdoor_mowers
A 21" Craftsman mower with a Briggs & Stratton 163cc 675EXi Gold Engine for $230 +tx.

(if you are interested, you can see my analysis on "How to compare mowers rated in HP vs ft-lb?", here:
https://bobistheoilguy.com/forums/ubbthreads.php/topics/2274273/1

The problem is it died. It worked only a week or so ago. The history is that last year my son refilled the oil reservoir with car engine oil (5W30) instead of mower oil.
shocked.gif
I did not know how to remove it
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so we tipped the machine over to get what we could out (not much) and re-topped it with lawn mower oil since then. So I chose to live with it as is
confused.gif
, with all the heavy billowing smoke in first few minutes of operation.
crazy.gif
This year, my wife thought the smoke meant there was not enough oil so she overfilled it with lawn mower oil.
frown.gif


This week, tried to use it and the cord won't budge. Not exactly sure the problem but the pull cord is seized, so not sure if it is the mechanism or the engine being seized. Called some lawn mower guys and they said they would service it for $120-150 + tx. The question is, is it worth trying to repair it or buy a new one as listed above for $300+tx?

Any feedback is welcomed.
 
The first thing you should do is take the spark plug out and make sure the mower is not hydro-locked. If the carburetor was dirty, gas could have flowed into the cylinder filling it and not let your starter (and cord) budge. If gasoline flows out of the spark plug hole after removing the spark plug, then you have a carburetor needle and seat issue, and you should be able to pull on the starter cord with success.

Also, filling the mower with a 5W30 automotive motor oil instead of a more expensive (and not necessarily better) lawn mower oil would not have hurt anything at all. The heavy billowing smoke you got after tipping the mower over to drain the oil out is completely normal.

You can also seek some advice from http://www.lawnmowerforum.com. There are several B&S Master engine mechanics over there.

I am not familiar with that particular B&S engine, but in general & in my experience, they are pretty decent engines. Heck, I have a 20+ year old Toro self propelled Super Recycler mower with a 5.5 HP B&S engine that runs as well today as it did when I purchased it over 20 years ago, and it does not burn any oil despite being used hard!

Good luck!
 
What you probably have is engine oil in the carburetor. The oil probably ran in there when you tipped the mower on its side to drain the oil out. The oil won't hurt the carburetor permanently, but it needs to be cleaned out. Also check the air filter for oil. Pull the spark plug out and get the oil off of it too. Next time you tip the mower, tip it back by pulling the mower handle to the ground and putting a weight on the handle to hold the mower in the tipped position. Tipping it that way will keep the oil out of the carburetor.
 
+1 In addition to with Merkava said, I'd take the bowl off the carburetor and clean the carburetor with the bowl off. Then remove the plug and either clean or replace it. Put it back together, make sure you have spark, and try starting it again with fresh fuel. The 5W30 oil didn't hurt the machine.
 
There is no such thing as "lawn mower oil." Lawn mowers use the same oil as cars do. Lawn mowers use "motor oil" and cars use "motor oil." Your son did not hurt a darn thing by putting 5w30 in the mower.
 
1) clean the air filter, there is probably tons of oil in there, clean it out. Reinstall.

2) Pull the spark plug, spray a bit of carb/throttle body/some form of solvent in there, yank start cord through a few times to clean and dry it out. Reinstall (consider a new sparkplug)

3) Ensure oil level is correct.

I'll bet a dollar it works perfectly after that.
 
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Yup , combustion chamber is full of oil. As said remove spark plug.

Buy a $50 mower off Craigslist

You said old mower broke before someone told you about it....? You not mowing your own grass? Bruh

Also did you forget the mower in the kitchen? Jk
 
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First of all. get it out of your head that automotive oil caused this problem because it is 100% incorrect.

Second. It only smoked after firing it up because you had it on its side which is normal.

Third. It's very unlikely the engine is seized. It's probably Hydro locked due to either Oil from being severely over-filled, or by fuel. Either way pull the spark plug and try pulling on the recoil. I'm sure it will be fine after getting whatever fluid out of the cylinder.
 
Pull the spark plug and flip it over and drain all the oil out. When you flip it over, you always do it so the carburetor stays upright. If you drain the oil with the carb on the bottom it will fill up with engine oil and ruin your airfilter.

If the engine is still seized after draining all oil and removing the spark plug, then your engine is toast.
 
Originally Posted By: Tman220
First of all. get it out of your head that automotive oil caused this problem because it is 100% incorrect.

Second. It only smoked after firing it up because you had it on its side which is normal.

Third. It's very unlikely the engine is seized. It's probably Hydro locked due to either Oil from being severely over-filled, or by fuel. Either way pull the spark plug and try pulling on the recoil. I'm sure it will be fine after getting whatever fluid out of the cylinder.


^ x2 ^
 
Sorry OP, have to laugh at the draining "auto" oil from the mower to refill it with "lawnmower" oil.

4 cycle oil IS 4 cycle oil. Basically, when the oil bottler puts "lawn mower" oil on the label, they mark it up 250% from "automotive oil" and you pay for that via ignorance.

When you read your engine manual, it says to use detergent motor oil with a rating of SJ, SL or higher. Since today's automotive oils are rated SN, which is higher than SJ or SL, clearly "automotive" oil is recommended by the engine manufacturer, and approved for warranty purposes..

Also, Briggs and Stratton's own oil recommendation prefers a 5W30 (synthetic) engine oil. They say it offers the best performance. Considering your location and climate, it would be hard not to recommend synthetic 5W30 (auto oil) for your engine.

If you found your engine's cylinder and crank case completely full of gas (which hydro-locked the engine), then the needle and seat needs replaced in the carburetor. The cheapest fix is to cut the gas line and install a fuel cutoff switch. The best fix is to install a fuel cutoff switch AND replace the carburetor ($20-30) if the needle and seat has failed.
 
Yeah I use Rotella T5 10w30 in my lawn mower personally. Diesel truck oil, OMG! I'm sure it's going to throw a rod through the side of the block any time now.

wink.gif
 
Originally Posted By: Brybo86
Yup , combustion chamber is full of oil. As said remove spark plug.

Buy a $50 mower off Craigslist

You said old mower broke before someone told you about it....? You not mowing your own grass? Bruh

Also did you forget the mower in the kitchen? Jk


That's exactly what I did last month. Had a Craftsman Platinum mower with a seized engine that I got from a neighbor. The deck and everything else was like new. Found an ad on Craigslist for an identical Craftsman with a bad deck and drive system. Bought it for $50.00 and swapped the engine. Runs fantastic

Only problem with Craigslist is every time I buy or sell something, the buyer/seller is always on the other side of town! I don't think I have ever had a transaction with a drive of less than 45 minutes. LOL!
 
I didn't read all the comments, but the ones I did are spot on. My summary:

1) "car oil" is fine for the mower unless its convenience-store garbage without any API ratings

2) The billowing smoke was from tipping the mower on its side. B&S engines have a crankcase breather on one side of the engine which evacuates the crankcase through a reed valve and spits the vapor into the carb. When you tip it on its side, liquid oil can enter the carb through that breather.

3) Over-filling the oil probably just submerged half of the cylinder, allowing oil to creep past the rings and fill the combustion chamber, forming a hydraulic lock.


So what you should do is:

1) Drain the oil out the bottom-mounted drain plug. Tip the mower over, locate the square-socket drain plug, and remove it with a 3/8" socket driver extension. Place a pan under the mower and tip the mower back on top of the pan. Tip the mower back up when its drained, and re-install the plug. Then set it back on its wheels.

Here's what you should see on the bottom of the engine under the mower. Be aware it will all be coated with grass guts and will be a uniform greenish/brown, so you may have to poke around:

check_oil_8.jpg


2) Pull the spark plug and spin the engine with the pull-cord a dozen times or so to blow the oil out of the combustion chamber. Clean up the mess.

3) Fill with the correct amount of quality oil of the right grade (usually 5w30- you can use "mower" oil if you want, but you can also use Rotella, Delo, or any ordinary passenger car oil like Pennzoil yellow bottle).

4) Start engine, wait for the inevitable smoke cloud to clear as all the oil burns out of the combustion chamber and muffler, then mow.
 
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I have yet to see a dead Briggs and Stratton engine.
Certainly don't think you killed yours. I think it's something to do with the emergency stop cable that runs to the handle. It locks up the flywheel when you let the handle out.
My neighbor ran her lawnmower out of oil, like no oil, black tar in there and dipstick nothing
Locked the motor up. I took the plug out and flipped the mower over and beat on the blade with wood till it would move and then turned it by hand to loosen the motor. Flipped it over, filled it with oil and got it running. It knocked but I used it for two weeks and it started to smooth out after several oil changes.
Sold it for $15 at the yard sale.
Neighbor was mad, they moved since then.
 
Originally Posted By: andyd
The easiest way to drain oil from a B+S mower engine is tilt the mower, carb side up and drain using the oil fill.

Easiest is to use a vacuum device to suck the oil out. I found a medical aspirator at flea market with glass jar. Put the 1/4 inch tube into wherever one can to get to a fluid and let it suck. Probably my best investment for small engines and vehicles. No fuss or mess.

Wish this site had a like or dislike feature. 440magnum had a very good post on the likely cure to the issue
 
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I once acquired a mower that couldn't even pull to start. They said I could have it.


Solution, the engine shut off brake's lever wasn't pulling the brake off so it was continually engaged. Once fixed, I pulled it once and started just fine. That was 15 years ago on a 1980's model Toro B&S and the only thing I have had to do to it since is replace the blade.
 
Originally Posted By: smayer97


The history is that last year my son refilled the oil reservoir with car engine oil (5W30) instead of mower oil.
shocked.gif
I did not know how to remove it
confused.gif
so we tipped the machine over to get what we could out (not much) and re-topped it with lawn mower oil since then. So I chose to live with it as is
confused.gif
, with all the heavy billowing smoke in first few minutes of operation.
crazy.gif
This year, my wife thought the smoke meant there was not enough oil so she overfilled it with lawn mower oil.

All my OPE's are running happily on car engine oil, and been doing that since the there first oil changes. Never had any of the problems you described. Otherwise than that, your other explanations of what happened I can see the problems you had. Follow the advice above.
 
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