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Hi

I love older Lawn Boys, probably form the 70's or so. Mine has the old pull start etc. I bought it used a year ago and it runs well but recently when mowing it will just stall out. its not long grass, it cna be anywhere, it runs for a while and then just sort of turns off. if i give it a couple pumps again it will start right up and run for a while again and then do the same thing

i don't knwo anything about doing a tune up or even where to get parts, but is there something I can do to get it running right again?

thanks so much

not sure of the year, but it looks just like the one in the second post here. it has like half the top cover

https://bobistheoilguy.com/forums/ubbthreads.php/topics/3358969/restored_lawn_boy_2_cycle

Hello Trock,
Your mower is approximately from the late 70's to 1980. The first thing I would check is the little vent hole on the gas cap. If it is plugged, your mower will act like you describe. The next thing I would check is the condition and setting of the carb float and the needle and seat. It sounds like something is causing fuel starvation.

Okay you have a nice F series mower from the late 70s or early 80s. Sounds like you have a fuel supply issue, probably just need to do an overall 2 stroke tune up, which will include, cleaning the carb, checking for good fuel flow from the tank, cleaning the exhaust ports and muffler, possibly replacing upper and lower crank seals. These 2 strokes really need to breath well and good seals, upper and lower, clean ports and clean exhaust are keys to getting a good flow of air through the carb venturi, without the proper flow of air and fuel mix through the engine, it will lose power and die. I think you can rule out ignition issues since it starts on a prime or two after it dies.

Lawnboy77 said:

Okay you have a nice F series mower from the late 70s or early 80s. Sounds like you have a fuel supply issue, probably just need to do an overall 2 stroke tune up, which will include, cleaning the carb, checking for good fuel flow from the tank, cleaning the exhaust ports and muffler, possibly replacing upper and lower crank seals. These 2 strokes really need to breath well and good seals, upper and lower, clean ports and clean exhaust are keys to getting a good flow of air through the carb venturi, without the proper flow of air and fuel mix through the engine, it will lose power and die. I think you can rule out ignition issues since it starts on a prime or two after it dies.

Click to expand...

I also agree with everything that Lawnboy77 says. The F series motor is one of the best motors that Lawn Boy made, but with age, certain things need to be done with them to keep them running strong. Seals, ports, and fuel systems will all need attention at some point. The good thing about an older Lawn Boy 2-stroke engine is that it is simple and easy to work on. You can also find most of the basic parts from a number of sources on the web. If they don't run right, it's usually a problem that is easily remedied and very much worth the time and expense. I have two Lawn Boys from that era and they run just as good as new. I have cleaned out the exhaust ports and replaced crankshaft seals on both of them, along with regular maintenance.

I agree with the above advice as well. I would start with the easiest first, the fuel cap. Maybe try to run it a bit with the cap loose and see if it still dies.
Boy some of the mowers on the link you provided sure look familiar ?

Hey All

wow thats a strange post above?

when i mow some gas will spit up thru the cap?

Thanks a ton for the help! and suggestions, is there any good youtube videos on maint? or a good place to buy parts that you all use? it's my first lawn boy lol, growing up l always loved them but we never had one. when i got to the point i had my own house instead of buying a new mower somewhere i went and searched this out and love using it!

i watched a video on an older lawnboy carb cleaning and will do that, but not sure about the rest

thanks much!

Lol....I said some of the mowers on the link you provided look familiar because six of them are mine.
Lee

ha! thats a cool link and that you own them!

i cleaned the carb last night, and sprayed it al out with carb cleaner but it still dies although not as much? and dies much quicker on a hill witht he left pointing down?

another thing that was odd is the on/off switch for gas flow seems to be backwards? but i have to check that. I had it to CLOSED when i started taking the carb off and it was flowing out of the tube. i switched it to OPEN and it appeared to stop. but, when i put it all back together and kept it CLOSED thinking it was OPEN it didnt start at all. so switched it to OPEN and it started.

very frustrating.

I will keep at it today, its a new sparkplug and cleaned out carb now. it spits gas up out of the cap whem mowing and full so i assume that is open.

I havent learned more yet on this mower like seals and stuff? and have been searching the web for videos on that.

I would love to get it running great again and could really use it now.

At this point I think it would be a good idea to pull the blade, blade adapter and muffler. Check the 3 exhaust ports are not restricted and also put the muffler on the BBQ grill on high for about an hour until the sludge is burned out, check out Youtube on "cleaning LB mufflers" for the how-to. The grilling technique is about the only way to clean the sludge out of those F series mufflers. While you are under there you can check and replace the lower seal if need be. Obviously if the seal has popped out of the crankcase then you will need to replace the seal, or if it shows signs of leakage, evident by oily grunge around the area. Replacing the seals are also easy, especially if you have the right tools, no sweat though if you don't have the special tools, common tools can be used, it just will take a bit longer to get the job done.

Below is a link to the manuals. ebay is a good source for parts, from my experience it's about the cheapest source for me, since I'm out here in the middle of nowhere Texas and no dealers around. Partstree is another good source I use, but will usually cost a little more. I also like to use the parts lookup on Partstree.com, I find it the most user friendly. Once you get the part number you need, then you can just google search using "Lawnboy and the part number" to search for sources. Alright just let us know if you have any questions. Sometimes these things are just a matter of "process of elimination" and all this stuff is preventive maintenance that needs to be done periodically anyway, so don't feel like you are wasting your time if this doesn't fix the problem totally, from my experience it is common to have more than one issue compounding the problem. My suspicions are that you will notice a significant increase in power by doing this cleaning of the ports and muffler. When you get a chance I would also pull the flywheel and check the upper seal for integrity to. One other thing to note on these F series engines that can hamper the ability of the engine to draw the proper fuel/air mix is a leak at the carb flange gasket, especially with a plastic carb, they have a bad tendency to warp causing an air leak which will take away from the air that should be going through the venturi and picking up fuel mix through the nozzle. Just put a straight edge on the carb flange to check for warpage and you can shine a flashlight on the back side of ruler to check for light on the opposite side, using this technique it will be obvious if the flange is warped. If you find a warped carb flange then you can use a sanding block and carefully sand it flat again.


https://lookup3.toro.com/ttcGateway/Acrobat/manuals/lball.html

Thank you so much for that info

I will do all that and report back, I am having fun working on it and I do love these old lawn boys!

ANother question I had is, do they still make the bags and chites for this? i would like to get a bag for it as well

on replacing the seals? are there any how to's you know of? youtube videos? i am not familiar with that part of it either

thnks for taking the time. I will try and get some pics up as well for everyone so you can knwo exactly what I have

thanks!

You are very welcome, glad to help. I'm not sure if there is a video on Youtube regarding replacement of the seals, however I know there are videos on removing the blade adapter. Of course you have the link here on the maintenance manual for the F series, I'll post a link below again if you don't. I suggest just reading through it really good. I'll also give you my cliff notes on the job, hope it helps! SAFETY FIRST! DISCONNECT THE SPARK WIRE PRIOR TO DOING ANY WORK ON THE MOWER. You can expect a bit of a challenge in getting the adapter off, and don't be surprised if it breaks in the process. If that adapter hasn't been removed for years you can expect it to be rusted in place and somewhat tough to remove. Heat, penetrating fluid and pressure is your friend. Pressure is via a big hammer and large brass punch, or pitman arm puller (The puller is what I use) No problem though, those adapters are still available through Toro, or aftermarket sources for a decent price if it gets bent, or damaged during removal. The process will be fairly straight forward. After the blade and adapter are removed, remove the 3 bolts securing the muffler and crank support to the muffler plate. Once the muffler is removed you can access the 4 ea. 1/2" bolts that secure the crankcase to the muffler plate, remove those while supporting the engine. Once the engine is removed it is just a matter of prying the seal out with a small common tip screwdriver by carefully prying in between the seal and crank. Those old F series cranks are tough, but if you want to wrap the screwdriver tip with some masking tape that would be fine. You obviously want to avoid scratching the sealing surface on the crank too much, or else the sealing maybe effected once you get the new seal installed. Once the old seal is removed just clean the crank in the sealing areas with emory cloth or scotch brite, or similar, nothing that is too aggressive though. Clean the area with some brake parts cleaner or similar, rubs some fresh oil on the inner sealing surface of the new seal and drive in place using a piece of PVC pipe that is about the same diameter as the seal and approx 12 inches long (needs to be long enough to clear the end of the crank), then drive in the seal with a mallet striking the PVC pipe until the seal is in just below the chamfer in the crankcase (about 1/8" below). Don't bottom it out in the recess, or else you run the risk of damaging the seal. When you put it all back together use a good anti-seize compound on the blade adapter-to-crank mating surface, "Never-seize" is a great brand and is what we use at my workplace, a good molybdenum disulfide grease (aka MolyB grease) is good to use as well. This will make removal of the adapter so easy the next time you have to remove it.


https://lookup3.toro.com/ttcGateway/Acrobat/manuals/lball.html

As far as the chute and bag options, you have a couple of options available. You can either mount a rear bagger setup to that model, or you can use the old school side bag set up with the prop rod that mounts to the RH rear handle bracket and goes through a hole in the deck, and at the top end holds the bag via a hook. This side bag option is probably the most popular and most available, the rear bag option is kinda rare and expensive if you can even find it on ebay. If you want to look at the rear bag option just look on Partstree.com, parts lookup for Lawn-boy model number 0292A, it list the rear bag parts drawing that would work for your machine.

wow, thanks again for the help, i will be checking out your info and reading

I def wanted the old school, side bag and chute. but wasnt sure where to get them for my mower or if they still existed. always wanted one with the side bag, just like in the old days!

i found this one one amazon but didn't know if it would work or not

https://www.amazon.com/gp/product/B...fl_title_30?ie=UTF8&psc=1&smid=A2RAAENK7AU3GY


thank you!

Yes that one should work for you. Below is my side bagger setup, which would also work for you, basically the only difference is the prop rod coming from the deck as opposed to the new one that you posted coming off the handle and the way the bag attaches to the chute, it doesn't use the black plastic slip over connection. You see these original setups on ebay quite often for a decent price. Hopefully this pic below will work, the last time I tried to post a pic it was a no-go.

oh, off the handle? dang i want one like yours lol

off the deck

I will keep trying to find one, any suggestions on where to get one?

I think ebay will be your best bet. Here are some listings that are currently on ebay. The bagger rod will typically be the most expensive item to purchase since it's still sold new by Toro/Lawnboy for around 90 bucks, you don't need a new one though, there are plenty of good used ones to be had on ebay much cheaper, or if you happen to live in area where Lawnboy parts are plentiful then you maybe able to pick up one at a local shop cheap. The older chutes like the ones in these listings are what you are looking for if you use the old school bags with just the metal wire frame on mating end. The one listing for the Cleveland Canvas bag is a great deal for the money, it's aftermarket and good quality and fit if you don't mind using aftermarket bags. It's plain white so you can stencil whatever logo you want to reproduce period correct Lawnboy graphics if you want. That's what I did on my 1966 restore. I'll try and post a pic below of that example just to give you ideas.

http://www.ebay.com/itm/Lawn-Boy-Mo...403554?hash=item4b15a0bfa2:g:4yAAAOSwSypY86ri
http://www.ebay.com/itm/Lawn-Boy-Mo...398929?hash=item4b15a0ad91:g:zxkAAOSw7U5Y86ml
http://www.ebay.com/itm/Lawn-Boy-Side-Bag-Chute-/322484899267?hash=item4b15990dc3:g:T84AAOSwvKtY8oSC
http://www.ebay.com/itm/Bag-Designe...553302?hash=item4399777b96:g:rncAAOSwcWdTdM84

Below is a link for the whole kit, plus a mulch plug, 85 bucks for used equipment is kinda steep in my opinion. You can probably do better by buying these parts individually.

http://www.ebay.com/itm/Lawn-Boy-Si...763188?hash=item33cc3b3074:g:WI8AAOSww3tY66j2

Very cool, I will check it out

I talked to a small engine mower repair shop and they suggested loosening the gas cap? to just try it. something about a vapor lock?

I re cleaned the entire carb again and started looking into the seals and things like that and ended up calling this shop who does work on old lawn boys. im not sure what that even means? loosen it? wont it keep spinning and sill gas?

should the little hole be clean? when i have mowed recently with a full tank the gas spits up and out of the little hole.

starting to get a little frustrated since I though I could have it fixed by now, and it wouldn't mow this weekend at all, same thing, starts fine, sounds good, mows for a couple minutes then just dies, prime it again twice, starts right up, same thing over and over.

Im also going to pull the muffler and clean it soon. i dont have a grill though, can i cook it on my stove without issue in the kitchen? wasnt sure about fumes etc but its the only hot thing i have right now

thanks

trock1985 said:

Very cool, I will check it out

I talked to a small engine mower repair shop and they suggested loosening the gas cap? to just try it. something about a vapor lock?

I re cleaned the entire carb again and started looking into the seals and things like that and ended up calling this shop who does work on old lawn boys. im not sure what that even means? loosen it? wont it keep spinning and sill gas?

should the little hole be clean? when i have mowed recently with a full tank the gas spits up and out of the little hole.

starting to get a little frustrated since I though I could have it fixed by now, and it wouldn't mow this weekend at all, same thing, starts fine, sounds good, mows for a couple minutes then just dies, prime it again twice, starts right up, same thing over and over.

Click to expand...

If you have gas coming out of pressure relief of cap I would logically assume you have pressure being created. The reed valves could be issue. Even though the reeds may appear fine they might have lost enough tension and do not seal. It could also be from leaky crank shaft seals (top and bottom of crank). I believe you can change the seals with out taking motor apart, The reeds you have to take case apart to replace them, If you replaced the reeds and seals, maybe worn rings, should also do a compression check at any rate. Good luck

Don't clean mufflers in the oven. We don't want to read about a house fire from someone cleaning a 2 stroke muffler in their home.

ha, thanks wont clean it on the stove then.

thanks for the help, trying to find all the stuff on the reed valves and seals.

I would love to get this mower working again. if it continues though I will look for another one for nwo to get me thru the season and work on this on the side

thanks everyone!

well just found a used 7260D for 125 bucks, 21 inch,

https://pittsburgh.craigslist.org/grd/6098855287.html

or

7261 with a new engine

says all carbs and mufflers cleaned and blades sharp

which is better? leaning towards the new engine one but don't knwo anything about these, or years etc?

thanks!

Well the model numbers are a bit mixed up. You basically have 3 F series mowers and 2 D-600s. 2 of those model numbers listed are D-400 machines and there are no D-400s there. No biggie though, probably just a deck, or engine swap at some point. I'd probably favor #3, it's a pre compliance F series pusher. Looks like they all have been well used, hopefully not abused. They are worth investigating in my opinion.

The commercial F series looks really great. That one would probably be the one to get in my opinion, the commercials really sell fast and will hold it's value the best of all of them. Why not buy 2? LOL

Ha! First thanks for the clarification on these. I read that some might be from 1972 or so and they def look well used. For me, just in terms of that classic look, I like the 2 I mentioned, I have always loved that pull up start cord. I imagine though the commercial one is better made? heavier duty?

but the 2 I mentioned I just love that look. for now to its a matter of having to get something that works lol. i can send the one I have to the shop and lead time could be up to a month to fix.

I wonder what to ask about the "new" engine? what would they have put int here? a lawn boy? or new from today and some other brand?

I was leanign towards the new engine one but if you think the other is a better model and overall mower I will go that way and save 25 bucks. Man, i really do love these. so many memories from youth wrapped up in them

i went on lawnboys website and jsut coudn't stand the new stuff.

You get whichever mower you like the best. They are all good models. Just do the usual checks, crank it and make sure there is no unusual vibrations, check that the deck is solid, no cracks, breaks or serious pitting.

trock1985 said:

well just found a used 7260D for 125 bucks, 21 inch,

https://pittsburgh.craigslist.org/grd/6098855287.html

or

7261 with a new engine

says all carbs and mufflers cleaned and blades sharp

which is better? leaning towards the new engine one but don't knwo anything about these, or years etc?

thanks!

Click to expand...

Wow, must be a better market in PA then in Omaha NE area, I usually see the same mowers here for 20 to 50 on craigslist. Also I would say the seller must be a LB fanatic not just your avg craigslist kind of seller.

I got an answer, kinda worried they didn't run? or maybe that's ok that some simple fixes from someone who knows what they are doing make them ok now?

Someone dropped off the one with the new motor because they couldn't get it started.
I took the carburetor apart and cleaned it. I think the gap was wrong on the coil too.
After all the work it started and runs well.
The other one wouldn't start. Most of the time either the coil is bad or the carb. needs cleaned.
This one just needed work on the carb. and it runs good too.

All mowers serviced with carbs cleaned, mufflers and exhaust ports cleaned, blades sharpened, decks cleaned.

Think its worth a shot?

well, talked to the guy, he and his brother are retired and they have worked on lawn boys, and other small engines for i guess 176 years lol. no seriously they have worked on the lawnboys for 40 or so years apparently, they told me what they do and did to them, and they will always take it back and fix it again. so off to actually drop mine off to them and buy a new one!

ill report back in!

I'm watching this thread closely because my 19" Lawn Boy does the same thing, but just recently started doing it. I've tried changing the gas cap, tried three different carburetors and replaced the bottom seal so far. It just seems like it's not getting enough fuel to the engine and the problem appears to be in the fuel tank itself. I'm thinking about trying putting an old round fuel tank on top of my mower and attaching a fuel line to my carb to see if the tank valve is my problem..