Smoking at start up is completely normal. Three things cause the excess smoke at start up: First the primmer system and/or choke adds extra fuel mix to get the engine started and this will add to the smoke. Second, some the oil from the the prevous run drains down to the bottom of the crankcase and pools there to be washed out by the incoming fresh fuel mix thus enriching the available oil to the combustion chamber. Third, the engine is cold and does not do a good job of vaporizing the fuel mix before it gets to the combustion chamber so the non-preheated fuel mix does not burn well causing more smoke than normal. An engine runs best at the operating temp that it was designed to run at and the carburator was designed to mix the air/fuel at, and running cold with extra oil makes it smoke many times more. However, if ever extra oil was needed it is at start up when the oil film is thinnest due to oil draining off parts of a long sitting engine. I have many two-cycle engines and all of them behave this way, it is just the nature of the design, enjoy. I hope this helps.

true, i have other 2 cycle equip that do the same, but they do not take as long too run normal. however dont you think 5 or 6 min is too long on the lawnboy?

That is a unusually long time, maybe you have fuel leaking into the crankcase and evaporating when the mower is not in use.This would leave a lot of extra oil to burn off. What is the condition of the fuel shutoff and float valve. Another thing, check and see if the air filter is soaked with oil before you start the engine. This could also mean a leak or a worn reed.

fuel shutoff is fine, but i dont close when not in use, only for the winter. as far as filter, sm amt of oil in filter as required. when you say leak, do you mean air leak?... have not checked float this year.

Fuel leak.

Everything as mentioned. How about a good quality oil that meets ISO-L-EGD or JASO FC certification? There are many good oils on the market these days, and any oil making this grade is either a semi or fully synthetic oil which will emit little or no smoke even during warmup with a properly tuned engine. I personally won't use ANY oil in my equipment today which other than my LB's are brand new other than an oil meeting this standard. What oil are you using now johnuch?

i have been using the lawnboy oil for as far back as i can remember(had the mower since 1985 new"

5 minutes isn't too long to warm up IMO. Lawn-Boys are fan cooled so the fan is running all the time. You may be a bit rich on the fuel but two-cycle engines like that. I use Mobil One Racing 2T fully synthetic oil in my Rejetted Duraforce and it smokes a bit for the first 5 min. I would start using the fuel shutoff valve when done mowing just to see if it helps.

Try a carb job. Replace the float, seat, and valve. These are relatively cheap parts and easy to do. ~$15 from your Toro dealer or www.rcpw.com. Look up your part numbers @ www.lawnboy.com. Its worth it! In my opinion, keep using the LB oil. Your 1984 (NOW 23year old mower) has done fine with it. No need for voodoo oil!

Boilers1, what's "voodoo oil"? I want to try some. I hear some here use it with great success!

johnuch; You need to overhaul the carb - it's running rich because it's leaking down. Understand one thing - smoking in a 2-cycle has only one cause - too much oil being burned because of either rich running or too much oil in the gas. Engine wear has nothing to do with it. As part of this process, I'd say also clean out the muffler and exhaust ports, because rich running really clogs them up.
Yes, you could change to a better oil at a higher ratio and reduce carbon build-up, but after you fix the problems. One commonly-available oil to start with is Homelite 'Exact-Mix' synthetic blend, found at Ace hardware. Mix at 50:1.

when you say leaking down...do you mean down in the engine or carb itself......carb is is not leakin outside right now....however i did have a leaking carb a few years ago, and got a new one.

What they mean by leaking down is that the shutoff valve operated by the float in the carb is allowing fuel mix to enter the carb even after the carb float bowl is full. Fuel then will flood in to the engine and cause an overich condition either while running or sitting. Most likely the leaking is not a lot but is enough to cause you problems. I suggested that you shut off the fuel tank valve to see if the smoking during warm up was reduced on the next cold start, that would indicate that you have a leaking valve in the carb. It could also be leaking while running, I have had this condition, lots of smoke, slow warm up, and surging. A new float, inlet valve and a good carb cleaning solved this problem for me.

please excuse my ignorance, but i am getting my feet wet with carbs. when you say "valve" do you mean as in needle and seat...is this the valve? thx

johnuch, have you looked at the parts diagrams for your model and also the service manual? You can view or download them free at Lawn Boy.

Here is a link that might be useful: Lawn Boy

I once mixed a batch of gas/oil, forgetting that I had
already done so a few days earlier, when I brought the
gas home. So the mix was double strength and smoked
quite a bit.

i can imagine....but was not the case here.

Yes, the 'valve' is the needle and seat. Probably just has some crud in the carb. Say, doesn't a mower that old have a needle valve on the carb for mixture control? I forgot about that. See if it does, and very gently close it while counting the turns. Open back up 1.5 turns and see how it runs - this may be too lean. Go by how it runs and amount of smoke - open the valve at 1/2 turn each time. If you get it running right with fewer turns out than it originally had, it was set too rich.

In a nut shell,Your carbs float needle valve assembly is either warn or has some dirt around it stopping the mating surfaces from making a good contact when the float is in it's up most postion (the float could be the culprit also) as the gas "seeps "past" the float needle valve it will overflow per se....and run thru the reed valves into the cylinder and down into the muffler and "pool", when you go to start the unit ,you prime it and it starts but it needs to burn off this excess fuel (loaded crankcase etc... and once it does it will still run fine ,maybe a tad rich ,but it will run .....the problem being is it will not fix itself,the easy repair is to just shut off the fuel to the carb......purist like myself repair the float needle and seat ,if it's possible to do so.....Good Luck,Jim

I would agree that this is likely a carb issue. My 10323 did that a few weeks ago... I ran it at my dad's house, came back a week later and the gas was gone. Refueled, and not only did the mower start hard but it smoked like a damn chimney for about the same time as yours. Is your mower hard to start prior to the excessive smoking?

not at all, believe it or not..

Although Lawn-Boys and 2-cycles in general like a wet condition on a cold start, it is possible to flood them and they can be ornery to start then. One trick is to take the plug out, ground the plug wire then vigorously crank it through several cycles to blow out the cylinder.

guys...doe this price for this combo seem right.. 92-9697 VALVE/SEAT-FLOAT ....? $5.64

That's what about I've paid for them.

Finally got my needle and seat for my lawnboy..."question"....the new seat has what looks like its all metal down to the tip...my old one looks like it is rubber or plastic at the tip...is this possible?.....and is it ok to use? .. i.e. the new needle.........second "question"....should i change my float too or for that matter how can i tell if its bad....thx ...... NEEDLE AND KIT # 92-9697.

Yes, you can use that style needle. The other type needles just help create a better seal at the seat, but then over time it will slightly wear in to where fuel will seep past and cause engines to run rich or even flood out. I assume you have the original cork float. They work fine, just make sure it's not deteriorated like pieces crumbling off from the coating they applied to it from the factory. Some kind of varnish or shellac to preserve the cork. Some here switch to the plastic style float, but what you have should work fine.

thx...."it will slightly wear in to where fuel will seep past and cause engines to run rich".... do you mean the all metal needle type will wear out quicker then my plastic or rubber tipped style...or are you just saying in general...

Stainless steel needle on a brass seat will wear less quickly than the others you mentioned. Either needle tip works fine. You may want to install a small inline fuel filter to help keep crud from flowing through and keeping the needle from seating properly. Even though Lawn Boy claims to use "tank filters" or even inline screen filters like found on the metal Walbro carbs, I've had small pieces filter through to hold the needle open enough to drain the tank out overnight by flooding through the carb and out the airbox. Some recommend fuel valve shutoffs, but I've had good luck by installing filters after carb overhauls.

sorry need to ask one more question before i finish this....should the float pin be crimped onto the float or leave it free ....as my old setup had the pin moving freely in float as well as on carb.........

Leave it free.

The float has to do just that-"float" on the pin allowing gas to fill in the bowl past the new needle and seat you just installed.

thx guys....i installed the needle and seat...float seemed to be fine so reinstalled that...started it up. ...i now have the famous lawnboy muffler off and this is the second time since the fall that i am cleaning it...this time there is a coating on muffler as well as bottom of engine of i guess oil and gas ...not that much carbon at all, same for port holes....just wet, that i can wipe off with a rag....i would assume it was from needle not seating properly?

Does sounds like raw, unburnt fuel/oil mix to me. Now that the carb issues are resolved, I'd expect this condition to wither away. Good job.

leaned in carb mix. a little ..cool, smoking just about stopped....but wish i had a tad more power or higher rpms'....has anyone used a tach. on the lawnboy too get the right rpm first before adjusting mixture or am i going overboard....

Depending on your air vane assembly (round or hexagonal)- Each click either clockwise or counter-clockwise is 50 RPM adjustment. The round is increased 50 rpm each click by turning clockwise and 50 rpm down by turning counter clock wise. This is opposite for the hexagonal shaped air vane assembly. Hope this helps!