White smoke from small engines

[Gerhardt]

Here's a question for Tom-D or some Tom-D-Wannabes. I buy 1-2 mowers each year, most with B&S engines, some with Kohler. At least once or twice each egine will puff a huge cloud of white smoke on startup when they're only a few months old. It may happen again every now and then, but not often. And they all seem to do that at some point, and they're not tipped at any awkward angles or anything different being done.

There never seems to be any harm, as the engines run fine afterward, but it happened with a new ZTR just last night and I glanced at the meter and there's only 100 hours on it, well after break-in period.

So the question is, what causes that?

 

[Geico266]

White smoke is oil buring off. B&S engines are not very precision engines and oil will leak into the cylinders from any number of places. Next time get a Honda engine.

 

[JHW]

white smoke is unburned or partially burned fuel or oil. All that white smoke you get when you cold start an old diesel, same thing. On your small engine you just had a misfire for some reason. Depending on the induction system, I'd probably suspect a momentarily too-lean mixture.

 

[EdFred]

It is oil buring off.

Or in the case of my mower when I started it this spring, it was oil being pressurized from the crank case thanks to ethanol poisoning in the carburetor which allowed the bowl to overflow into the cylinder. Then into the crank case, and when I started it, pushed the gas/oil mix back into the cylinder.

That was more than a puff of white smoke. Luckily the station closest to me sells 91E0. So that is what will be going into all my yard equipment and motorcycle from here on out.

 

[bnt83]

Tom-D-Wannabes.

 

[1600vw]

B&S has a bulletin about this. I don't want to be a Tom D wanna-a-be so I will stop here. Find it yourself.

By the way it has nothing to do with fuel. But everything to do with the oil. Its getting into the combustion cylinder while setting.

Did I mention I am a factory trained B&S tech.

Tony

 

[Gerhardt]

B&S has a bulletin about this. I don't want to be a Tom D wanna-a-be so I will stop here. Find it yourself.

By the way it has nothing to do with fuel. But everything to do with the oil. Its getting into the combustion cylinder while setting.

Did I mention I am a factory trained B&S tech.

Tony

These mowers get used dozens of times each day, which leads me back to my poorly-phrased question. I should have asked...what causes that to occur that one time, but no other time that I start it up?

ex. yesterday we'd mowed maybe a dozen lawns, and when I start the mower for the 13th time for the day it belches the huge cloud of white smoke. It always startles me at first, then has me curious. It's not just a B&S issue, as the same thing happens with Kawasaki, Kohler, Tecumseh, etc.

 

[Stewartb]

I suspect it's related to valve position and oil draining into the cylinder. BS motors I've owned all did it. Hondas do not. Who cares? If it ain't broke, don't fix it.

 

[Henning]

These mowers get used dozens of times each day, which leads me back to my poorly-phrased question. I should have asked...what causes that to occur that one time, but no other time that I start it up?

ex. yesterday we'd mowed maybe a dozen lawns, and when I start the mower for the 13th time for the day it belches the huge cloud of white smoke. It always startles me at first, then has me curious. It's not just a B&S issue, as the same thing happens with Kawasaki, Kohler, Tecumseh, etc.

Most likely valve guide wear.

 

[flyingron]

Either that or someone has been elected pope.

 

[Henning]

Either that or someone has been elected pope.

Is black smoke an omen a will die?

 

[1600vw]

These mowers get used dozens of times each day, which leads me back to my poorly-phrased question. I should have asked...what causes that to occur that one time, but no other time that I start it up?

ex. yesterday we'd mowed maybe a dozen lawns, and when I start the mower for the 13th time for the day it belches the huge cloud of white smoke. It always startles me at first, then has me curious. It's not just a B&S issue, as the same thing happens with Kawasaki, Kohler, Tecumseh, etc.

Yes that is what they do when you have this problem. There is a fix and it has nothing to do with the combustion chamber. But it does have everything to do with the oil.

All I will say, for what do I know.

Tony

P.S. The fix is so simple its funny.

 

[PaulS]

Yes that is what they do when you have this problem. There is a fix and it has nothing to do with the combustion chamber. But it does have everything to do with the oil.

All I will say, for what do I know.

Tony

P.S. The fix is so simple its funny.

Come on tony, give it to us, this is the intrawebs, it's almost a requirement to give an answer, knowledge, accuracy or even the correct answer are not prerequisites.

 

[1600vw]

Its in the crankcase vent. If this engine was just serviced and this vent was removed it was installed upside down. If it has not been serviced for a while and this problem just peeked its ugly head, the vent is plugged. But I would bet it got installed upside down. The vents need to point down. If the vents points up, oil can get into the vent when you do things like go up a hill. Sometimes it can just flow down into the vent from off the walls of the case. Its in the crankcase vent. Make sure its installed correctly and clean.

Tony

 

[docmirror]

Since one person has decided to play stump the chump, I'm going to bite the apple and advise checking the crank case vent to the intake after the filter. Changes have been made in small engines that reduce the crank case vapor back to the air, and now dump that oily gunk into the intake. Either vent it to the air(prolly illegal) or check to see if there's a gummy mess in the breather tube and clean it out periodically.

edit: Seriously, I was typing mine as the above was being posted.>

 

[1600vw]

Years ago B&S had a problem with engines coming from the factory with this vent installed upside down. Every now and then the engine would blow a big puff of white smoke. The fix was turn the vent the right direction. It cost B&S a lot of money fixing this simple problem.

Tony

 

[Geico266]

Or in the case of my mower when I started it this spring, it was oil being pressurized from the crank case thanks to ethanol poisoning in the carburetor which allowed the bowl to overflow into the cylinder. Then into the crank case, and when I started it, pushed the gas/oil mix back into the cylinder.

That was more than a puff of white smoke. Luckily the station closest to me sells 91E0. So that is what will be going into all my yard equipment and motorcycle from here on out.

You should install a shut off valve on the fuel line.

 

[EdFred]

You should install a shift off valve on the fuel line.

I did that very thing a couple weeks ago. First time I got hit by this situation in 14 years of owning the mower. Now I flip the hood open, shut off the fuel, and let the engine run till it dies.

 

[Geico266]

I did that very thing a couple weeks ago. First time I got hit by this situation in 14 years of owning the mower. Now I flip the hood open, shut off the fuel, and let the engine run till it dies.

Nicely done!

I've had it happen a couple of times until I installed shut off valves. Except now I have to have a check list to start the mower.

 

[PeeGee]

Next time get a Honda engine.

x2
let a friend talk me into a mower with a B&S after years of hondas. NOPE. Never again.

 

[PaulS]

Those honda engines have their quirks too. Besides being ridiculously expensive, you have to keep the valves adjusted, otherwise they will burn, stick open and broach a hole in the piston.

 

[Gerhardt]

Regardless of brand, I've never had an engine wear out on me before the rest of the mower has fatigued. I go through a couple of 21" mowers each year, a 48" walk-behind every 3-4 years and replaced the larger walk-behind with a ZTR last year. At the first sign of wear I replace the mower because I can have zero down time on any piece of equipment. The drivetrain is usually the first to go.

To be honest I've never really noticed a difference in the performance from one brand to another, and over the years I've owned scores. My take on this is that it's a Ford - Chevy thing. Most people love one and think the other is a piece of junk.

 

[Henning]

I have a question for the pro lawn guys, what is the pro/con between the stand on ZTR type platforms and the sit down?

 

[1600vw]

I have a question for the pro lawn guys, what is the pro/con between the stand on ZTR type platforms and the sit down?

It has to do with ease of use. On a commercial unit one gets on and off a lot. Its easier to just step off then climb on and off. That is the only difference. Its an operator thing. Myself I would not want to stand on one and take a beating all day. Let the suspension of the seat take some of the shock loads placed on ones body from operating these things all day. Who ever came up the the standup unit needs to ride one for 8 to 10 hours non stop. I bet they would never design another.

Tony

 

[Henning]

It has to do with ease of use. On a commercial unit one gets on and off a lot. Its easier to just step off then climb on and off. That is the only difference. Its an operator thing. Myself I would not want to stand on one and take a beating all day. Let the suspension of the seat take some of the shock loads placed on ones body from operating these things all day. Who ever came up the the standup unit needs to ride one for 8 to 10 hours non stop. I bet they would never design another.

Tony

Ok, that kinda parallels my thoughts. With back and knee issues, I just had a hard time understanding why people chose the stand up ones, because from what I have seen, the prices are similar enough not to really matter, that is to say both price tags on the pro grade machines made me go...

 

[PeeGee]

Those honda engines have their quirks too. Besides being ridiculously expensive, you have to keep the valves adjusted, otherwise they will burn, stick open and broach a hole in the piston.

the one before my last honda ran for 20 years without so much as a tune up or oil change, I then sold it at a garage sale. The last one went with a house, then I bought this stupid B&S torro.

 

[PaulS]

the one before my last honda ran for 20 years without so much as a tune up or oil change, I then sold it at a garage sale. The last one went with a house, then I bought this stupid B&S torro.

you were lucky or it was not an overhead valve or you didn't have many hours on it.

 

[Henning]

you were lucky or it was not an overhead valve or you didn't have many hours on it.

I have had Honda powered OHV trash pumps for many years in commercial/salvage/emergency response rolls as well as irrigation and work site dewatering, and I can think of no other piece of equipment that has been so neglected yet so reliable in my life. I have never adjusted the valve on one nor lunched one, even when I ran one for 3.5 weeks solid getting a damaged barge to port. You are the first person I have heard of complain about them.

 

[pigpenracing]

Here's a question for Tom-D or some Tom-D-Wannabes. I buy 1-2 mowers each year, most with B&S engines, some with Kohler. At least once or twice each egine will puff a huge cloud of white smoke on startup when they're only a few months old. It may happen again every now and then, but not often. And they all seem to do that at some point, and they're not tipped at any awkward angles or anything different being done.

There never seems to be any harm, as the engines run fine afterward, but it happened with a new ZTR just last night and I glanced at the meter and there's only 100 hours on it, well after break-in period.

So the question is, what causes that?

Not only do small engines puff white smoke on startup.




https://www.youtube.com/watch?v=f_EpvEN_hBk

 

[PaulS]

I have had Honda powered OHV trash pumps for many years in commercial/salvage/emergency response rolls as well as irrigation and work site dewatering, and I can think of no other piece of equipment that has been so neglected yet so reliable in my life. I have never adjusted the valve on one nor lunched one, even when I ran one for 3.5 weeks solid getting a damaged barge to port. You are the first person I have heard of complain about them.

It wasn't a complaint, it was an observation. If you don't keep the valves adjusted they will eat one, at least the 13 hp gsx. My lawn guy has had two of them go on leaf blowers, one he gave to me and I rebuilt it.

Is there anything you haven't done or any piece of equipment you haven't used?

 

[Henning]

I know very few people who have worked in any industry who don't have experience with a 4 stroke Honda engine. A 13 hp leaf blower is an interesting thing to try to picture.

 

[1600vw]

I know very few people who have worked in any industry who don't have experience with a 4 stroke Honda engine. A 13 hp leaf blower is an interesting thing to try to picture.

 

[1600vw]

Back in the early 90's B&S purchased all of Honda's engine line of small engines. Honda revamped their engine line and sold all thier NOS to B&S. This is why if you purchased an OHV engine from B&S is said made in Japan for those where indeed Honda engines.

 

[timwinters]

"Next time get a Honda engine."

I have about twenty small engines out in my barn of all varieties and my least favorite are the two Hondas. One is in a Bush Hog brand side-by-side, the other in a log splitter. Both are twins. They are the quirkiest most cold blooded, hard to start, won't idle until thoroughly warmed up, engines I own. Both have been back to the shop more than once for tweaking, have had plugs changed to hotter ones, etc. they're better, but still nowhere close to right.

The best, most reliable engines in my barn? The Kawasakis that are in my ZTR and DR Brushcutter. Both of those are twins too and both have run for hundreds of hours with nothing more than annual oil changes. One is 15 years old, the other six. They start when asked and purrrrrr.

The various Briggs in the barn do just fine too. I have an ancient wood chipper/leaf shredder with a Briggs that runs once or twice a year and an old generator that I never use and that is fired up once a year to test it and change the oil. They both fire on the first or second pull (once primed), every time. The little generator has a full tank of gas run through it and sits for another year.

Anyway...the bottom line...I'm no fan of Honda...not the ones in my barn anyway. Kawasaki yes.

 

[Gerhardt]

I have a question for the pro lawn guys, what is the pro/con between the stand on ZTR type platforms and the sit down?

Two major differences, and why standers became incredibly popular overnight. The best part about standers is control. You can take hills much more easily and they are a lot more manueverable. Tire size is everything on a ZTR when it comes to control, which is why commercial units have much larger tires than those made for homeowners. Talk to anyone who has taken a sit-down Z on wet turf or a hill and you're talking to someone who has lost control and has learned his lesson.

Standers are also nice because almost all of the mower is the deck, so you can get in tighter spaces that a Z can't. None of them are cheap, but standers will make you pucker when you see the tag.

For steep hills nothing is safer than the old walk-behind units that are falling out of fashion. MUCH more control.

 

[Florida Cracker]

White smoke is oil burning off....

OR it means they've chosen the next Pope!

 

[JGoodish]

Commercial stander mowers are almost as expensive as commercial ZTRs. In addition to what Gerhardt mentioned, some guys also like them because they take up less space on the trailer, but there's no way I'd want to ride all day on one of them in open space. It's a tool that has a complimentary set of strengths with those of a ZTR.

The engines used on larger commercial mowers aren't the homeowner variety, and Honda doesn't really have much of a market presence with those types of engines. Kohler, Kawasaki, and B&S seem to dominate. The B&S Vanguard engines are highly regarded, even perhaps more so than the other two.

I own a commercial Kawasaki air-cooled engine and have been significantly unimpressed with Kawasaki's warranty support. I have a Honda commercial engine in another piece of equipment, and have had nothing but reliable performance from it. I also have a couple of Honda "consumer" engines, and they've been okay, but they're throwaways. I doubt that they would stand up to commercial workloads for very long.


JKG

 

[jsstevens]

Most of these engine manufacturers have both consumer and commercial engines. I know Honda and Briggs & Stratton did. (Haven't looked in a while.) The commercial engines had thicker, cast steel cylinder sleeves and much better bearings-along with other upgrades. They lasted a long time. The consumer grade ones, not so much.

I've got a mower with a 9HP Kawasaki (commercial) that has been great. First or second pull start for 6 years even when not run all winter. The only problem I've had with it is the compression release has a bent shaft and is intermittent. Sometimes you go to pull the rope and it yanks the handle out of your hand. Since they wanted more than $200 to fix it and I'm used to it I said "Never mind."

John

 

[1600vw]

B&S engines use a compression release as do others. Its a spring operate mechanism on most. When starting sometimes you will hear this spring pop back or it makes a popping noise. Some owners believe the engine has problems but its just the spring snapping back. Sometime it will do this while idling if the idle goes to low. The compression release starts to get in at real low idle.

Yes B&S do have commercial grade engines. They have I/C on them. Industrial / Commercial.

Tony

 

[1600vw]

Not only do small engines puff white smoke on startup.




https://www.youtube.com/watch?v=f_EpvEN_hBk

Just imagine if every small engine did this. There are millions of small engines in every state of the union just on push mowers. Imagine the amount of pollution we would have if ever lawn mower in America did this on start up.

This is why you no longer see chokes on any small engine. With there being millions of these little engines in use the EPA banned the choke system. They did this because on start up, that is when the most pollution was being produced. It was because the choke systems ran so rich during start up. To lower these emissions the EPA did away with all chokes on small engines.

The EPA is also regulating small engines in the 24 hp and lower range. This is why we are seeing 4 stroke weed eaters, and chokeless lawn mowers, they now use a primer bulb, less emissions. The EPA would like to do away with all 2 stroke small engines because of the emissions they give off. They had a date of 2012 set but could not met that date. So know its 2020. Things like carburetors will be gone. In place will be EFI. Electronic fuel injection. You will start seeing these on your lawn mower in the near future. They have been working on these systems now for a decade.

Some info on the small engine and where its heading.

Tony