I have quite a few of these style Briggs & Stratton engines. I worked 13 years as a cemetery caretaker. Anyway, one thing worth mentioning, that you didn't , is warpage. Specifically, the gas tank top and the carb base. I had on more than one occasion warpage on these parts. One mower was so bad it still ran with the mixture screw turned all the way in. Check with a good straight edge ( I have a Snap On Professional straight edge) . If warped, use a FLAT stone on the gas tank till all shiny. On the carb, take out the plastic pick up tubes and lay a very fine sandpaper on a FLAT surface and rub the carb till all shiny . This should take care of any warpage problem. Anyway, just my 2 cents worth.

Thank you very much - after 10 years this video enabled me to confidently disassemble, clean and put back together the carb on our ancient lawnmower. Now it works as new. Those intake meshes were clogged on mine.

There you are, 13 years later, saving my life

I'm working on an engine like this, from a 1985 Murray 20" mower. It ran great in 2015, but was submerged completely in a 2016 flood. Carb is similar, but not exactly the same as yours, only one pickup tube into the tank, same thermostat controlled choke. I'm waiting on a diaphragm because the choke rod came off from corrosion of where it meets the diaphragm. Drained water from crankcase after 4 years, filled with charcoal lighter and mixed it up. Will drain and fill with transmission fluid and run it until warmed up, then drain and fill with oil. It'll be fine. ;) I have other videos on my channel of a flathead 5hp that went through the same, and a Craftsman chainsaw I got running again. I will add more as I go through all the stuff sitting around here since the flood. Lockdown gave the time to tinker.

I just want to thank you for all your videos,I work and try to restore older machines and you usually cover them. Thanks again Donyboy.

I love the sound of those old flatheads running, takes me back to my youth!

Thank you never knew that trick with air filter bolt in the carb. Glad you video old tiller I have a similar one but, our carb has no auto choke. A harder time to find a video for old Briggs.

These old 8X and 9X engines were so tough. Many of them outlasted the equipment they were bolted to. Briggs learned their lesson, and cheapened them little by little.

Yeah this video really helped with my Briggs/Stratton engine that wouldn't start. Took me awhile to go through it all, but I never would have even attempted without this video. Three pulls of the cord and it started, and the front lawn was mowed before dark. Thanks for the detailed instructions!!

Awesome vids. I was about to throw my old girl out. She was running rough and blowing so much smoke I couldn't see 2 feet ahead of me! I'd pulled the carby apart before with limited success, but after following your instructions she just purrs and not even the slightest puff of smoke. My decrepit old mower is now running like she just came out of the factory. Thanks for the excellent videos!

i watched yur vid because ironically enuf im working on the same tiller..ran like a bat outa hell till it warmed up ..now i know the choke is sticking.. thanx tons!!!

Thanks, I just bought a non-working '68 toro lawnmower with the same motor for $5. After cleaning the points I now have spark. Next the carb. This video is exactly what I need for that.

Like seeing an old family movie compared to your current ones. Still very useful as I need to rebuild the carb on a 30 year old 3HP leaf blower. Thanks, fingers crossed.

My Briggs & Stratton Magnetron 3.5 HP has the same carby as this one and now I will try to revive it based on your tutorial. Thank you very much.

Very good video. Better than most. Nice close ups and good narration.

Your an excellent small engine and equipment mechanic, I learn something new everytime I watch your videos! Thanks for all the great tutorials!

I just repaired the neigbours like this one, put in a new diaphram and lots of cleaning . Thanks for your video really helped me out. Those have small holes in them to clean.

Nicely done. Well explained. And even thought the video is 6 years old the camera work is solid.

OK, I got it running. It wasn't the same exact one. It only had one of those plastic tubes with the screen. My screen tube was plugged and the gas was old. Thank you again.

You did a great job explaining that carby service. Well done!

Great videos. I love the way you ffwd through the slow parts and didn't put any BS in there. Perfectly done. Great step by step instructions. Thank You very much and keep the videos coming.

I have a 1980s snapper self propelled 3.5 hp that would not start. Thanks to your video it now runs like new. Starts on the 1st pull!

Thanks for the video as it is hard to find videos of these older carbs without the primer bulb. I watched your video to find out where the spring and cap go. My spring and cap had been placed in the top of the tank underneath the diaphragm, but you mentioned that the spring and cap should have been installed in the carb above the diaphragm. Thanks!!

That old tiller is hitting a lick, good job.

Holy cow! I have been having trouble with getting these to stay adjusted or idle right and everyone of them have had the spring on the bottom side when I took them apart. No wonder, thanks dony! Can't wait to get these opened up and corrected to see if I can get them right again

Darn... I was working on a 4hp tiller from 1964 and the screen on both were extremely blocked and I was only able to get them partially cleaned... It's running but seems to be real finicky with the throttle lever... Thanks for getting back to me!! Though its not just exactly perfect it did till the garden... Engine seemed to wanna die if I leaned it back to far while using it. Thanks again!

Thank you my dude. You old movies are also helping people every day. I just bought a walk behind sickle mower with a old briggs 3,5 (92902). Mine starte beautifully but only ran a few seconds before stopping. One of the filter screens were completely clogged. Thanks to your video I was able to go in there knowing what to expect. Any recommendations where to buy a carb kit with diaphragm? Mine is probably 20-30 years old

Excellent video. I followed it step by step and got my lawn mower working again. Many thanks for your time and greetings from England..

That's awesome. I just bought more or less the exact same tiller but with the B&S 3hp engine. It all needs a good clean out but now I think I know how. Thanks!

I plan on cleaning this same design carb. when I get back from Church in the morning. It's on my B&S Speed Clean pressure washer that I've had for about 7 years! 3.75 hp I think. Will be the 1st time I've had to do Anything to the engine. It runs pretty good under a load, but when it's at full throttle and NOT under a load the engine surges up and down Very badly. It's almost wanting to die out! Been a real dependable pressure washer, but I've kept the maintenance up too. I love B&S!!

@grf01000 there is usually a terminal by the carb linkages with a wire going to it so that when u pull throttle back it shuts it off, it's under the air filter near where the cable attaches

An excellent video. Now I know what to do with my mom's B&S. Thank you again Dony.

Great Video. Lots of detail and easy to follow instructions. You helped me diagnose my choke problem.

Thanks for the videos , it has saved me money and got the satisfaction of repairing myself

Badass job!! Brother u most likely r a mechanic if not you should be get that running

You're a natural. Big thanks from Melbourne Australia

Don, This is what I was looking for I just had not gone though all your vid's the Briggs that I have is a 5 hap Hoz shaft with a pull choke ,, It has been around for ages not sure when my dad bought or for what at least 35 yrs?? I will have to check the # on it to see when the D.O.M. was. It has been stored I it last year and put Methanol gas it it. Now it is just start and stop. John from Oregon.

All in all a nice guide, I'd like to add one thing. Before you tighten the screws holding the carb to the tank, check that the choke-linkage is connected and depress/turn the choke-plate (the white plate with the hole in the middle) to it's fully open position and let it pop back. If you don't do this, the choke might not work properly, since it requires a bit of preload. Not knowing this caused my engine to run rich. The mixture screw seemed to have no effect.

Great video on the subject. I will be going back to this video when i fix my mower. I believe my mower has the same problem. Thks for posting.

10 years later, I watched this and, yep, I was putting the fuel pump spring on the wrong side of the diaphragm . I runs now.

You're the man donyboy!! I put that darn spring in backwards. Thanks a bunch!

thanks..very helpful..these old machines are too good to get rid of..

Followed your guide. The mower works great now!

Well done 😺

I have two of these engines. One on my engine reel mower and the other I made use of to build my chipper. As I remember the service manual states for carb adjustments yo be done with two thirds tankful is gas.

one is a lift tube that pulls fuel into a fuelbowl, and the other tube goes from the bowl to the jet. The fuel bowl doesnt need a float, because it has a hole cut at the top that drains excess fuel back into the tank

Thank you, my vintage Snapper mower was new in 1973 when I purchased it. Your 3.5 hp motor looks very similar to it. I can't part with it.

Even with the spring off, I can work the butterfly and there is no increase in the idle. As long as it is at idle(which is rough) it stays running. When I try to operate the linkage to the governor/carb it smothers out.

I have a motor just like this! Sitting since 1986 and just placed on a mower! Has spark, CJ8 plug. Will run some on EITHER but quits VERY HARD TO pull over! Both valves at .008" Cleaned tank and carb and used NEW 90 non ethanol,old Gas turned to black coffee. Diaphram seems to be ok. Any ideas on the HARD to pull? Also pulled flywheel and set points to .020" with light sanding. Key is good on flywheel. Motor was on a ROTO-TILLER identical to yours!! Running when we moved in 1986! I am at a loss on this one!! Any help or ideas ? Thanks

problem I'm striking on older B&S engines, 80s mostly, with die-cast metal carbs..(I just replaced one an hour ago with another used carb, I used one of the slightly later plastic ones, plastic but no plunger button )is this issue where a highly rich condition develops...the engine starts and runs, but clearly runs -very- rich, a visible soot-smoke discharge from the muffler...the plug of course quickly develops a dry black soot coating..when you screw the mixture screw in to full-lean even, right up to the stop, on a carb working properly this would normally lean off so much that it would stall the engine, but when engine has this problem, it is so rich that screwing in mixture screw cannot stall it even...I have seen this condition just on those old metal carbs several times now, exact same symptoms, all I have done is swap carbs to one working ok still, but what specifically causes this, I'd prefer to fix them if fairly easy.. Show less

@seasonedtoker no, just find a cast iron flywheel if u can find one!

Rukle of thumb is to back the jet needle screw out 1.5 turns not 2 turns, sometimes 2 turns is so rich that it won't run at all I have found. Also you should have the air filter on when you tune the carburetor. good vid though I'm sure people will find this helpful :)

The spring and the cap, :D thank you for showing where it goes! Great tutorial thank God for KZfaq and Donyboy73...

you're welcome Alan

@blitzkriegdaven thanks for watching

i would have to doublecheck but i think they are pressed in, sometimes they break when trying to remove them

Great vid thanks for the help, am going to try this on my unit. Also that little engine runs lovely after you fixed it, sounds perfect. Nice work

try adjusting the screw at the back of carb, or replace the diaphragm, it could also be low in compression

Thanks. Followed along... now working.

yes this is a much older video and not in HD as my newer videos after 2011

on these engines the air filter screw has to be in for the choke to work properly, you may need a new diaphragm

Very well detailed and cut video. Extremely useful.

@JosephHua the H screw might need to be turned out a bit

@edwoodsworth you're welcome

@seasonedtoker u need a cast iron flywheel, much heavier or it will kick back hard

@MrDennis8805 thank you sir

Thanks a lot. I didn't remember where that spring belongs. (that's the reason why i came to see this video)

why do you make everything look so easy!

I didn't take the small cover off where the jet is either. Could that be blocked? I also noticed there's just one spring and one linkage, how can I tell if they're working correctly and in the right place?

you can replace the diaphragm and maybe try adjusting the carb

Do you recall the model number of that Viking tiller. I have the same one and need to see if I can find parts.

@raygabmiamizzi the tighter the throttle spring is the faster it will rev

Thank you, i showed this to my dad and it helped him a lot :)

make sure to replace the small diaphragm on the side of the carb

i have done more research and found out what the numbers on the model and type mean its a 13 cubic inch witch makes it a 5hp and date is march of 75 thanks

@boat6868 thanks

great someone who knows what theyre doing! The rod mentioned at 3.18 mins how long is it? were some made with a spring instead of the rod?

Your videos were great. I was left with a situation though that I hope you can help me with. The mower would only run with the butterfly wide open until I cleaned the carb (with your video). Then it started second pull and mowed very tall grass like a champ. Even had to restart it twice (pilot error, not the mower). Worked great. Then I took a 10 minute break. It hasnt tried to start since? Do you know what's wrong? Clean everything. Tank, carb etc... Fresh gas. Thanks in advance and thanks for the video!

Great videos! Staight to the point. I got my lawmower working with this vid. Thanx!

@grf01000 or you can some how attach a wire from the positive end of the spark plug and then put it on the frame to short it out

Just wondering what holds the spring from falling off before you install the diaphragm to the fuel tank.Rely enjoyed watching .

I have a motor exactly like this and it runs great how old Is this engine? Thanks in advance!

Hi..I have watched your video's and learned quite a bit..the problem I'm have now is the governor..how do i adjust the governor..thanks

@raygabmiamizzi thanks for telling me

you should be able to by taking the camshaft out of one and the cover and swapping it to the good motor

thanks

Great video donyboy73! Keep em coming!

I cleaned the carb and replaced the diaghphram. The mower runs, but I cannot rev the engine. The adjustment screw has no effect on the idle. Any suggestions.

@You2ube54 thanks dude!

Fantastic video, very informative, I've got the same motor/carby, just replaced the jet valve, but I still can't get it to start without pouring fuel down the carby throat,even then it only runs for 20 seconds and dies, would having the spring/diaphragm in the wrong order stop it from running? bearing in mind it was in the wrong order for 35 years and ran ok!

brilliant video. thanks so much. I have a similar B&S engine, and the fuel uptake tube is clogged, casnot get it cleaned. . I think I need to take it off to clean it, but dont break it or the brass tube it is attached to. Mine is longer than the one in your video, the plastic part with the screen slides on to a brass tube about 3 inches long. Does it screw off, or is it just a press fit? How much effort do I need to apply to get it off? Can you suggest any secrets for removing it? thnx

hello I'm Italian and I thank you for the excellent video, I would have a problem of the type that my engine is not equal to the highest takes the turns and turns off if accellero and makes the black smoke, up to 3 days ago gave no problems, however, I had cleaned the carburetor but has not improved .. you know give me a hint? thank you and excuse the bad language

The only way to keep my motor running kid to place a screwdriver down beside the choke. The motor runs smooth, but I cannot rev the engine without it dying. If I remove the screwdriver from beside the choke it closes and dies. I have taken the carb off three times and checked the springs. Everything looks just like in your video. Any ideas why the choke is not operating correctly?

Where can you get new diaphragm for this engine? Need one. Thanks.

@CCSinventions i see no oil involved in this and ive worked on worse things than this and if u get stained it goes away in like a week so yeah...

it is possible that enters oil in the piston? I think ultimately a lot of oil consumption how can I fix this problem without doing any worse trouble

@OB1974 thanks

@ronatdeepcreek thanks

I noticed that you forgot to put the pump spring in. When you rebuild the carburetor did you have terra back apart.

@Zoltan2012AD i would have to see it but i imagine if it came like that it should work