CARBURETOR Repair on Older BRIGGS & STRATTON 3.5HP Engine Part 2 of 2

[@matthiasmartin1975]

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.

[@Mike-vi9do]

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.

[@mjg263]

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

[@leshall3013]

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.

[@donyboy73]

+Les Hall you're welcome, have a good evening

[@tonyfremont]

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.

[@tonyfremont]

Video available of it running now. Got the carb diaphragm, just need to install it and an air filter. Ready to go. A customer is bringing me the same thing from 96, it has sentimental value to them.

[@SexcAzn100]

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!!

[@frankhutchison2382]

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.

[@fair2middlin]

There you are, 13 years later, saving my life

[@MrJoeMaz]

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.

[@charger19691]

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

[@rickwarden2089]

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!

[@ziadbouz1]

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.

[@toddhart3787]

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!!!

[@HB-yq8gy]

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.

[@kingtut5923]

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.

[@talan411]

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!

[@suchfunstuff]

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.

[@MrJoeMaz]

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.

[@thomasjohnson9768]

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.

[@davidcurle119]

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

[@donyboy73]

you're welcome, greetings from Canada

[@dale797]

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!!

[@degas280677]

I pulled mine apart and found the same thing

[@funkrusher]

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

[@donyboy73]

+funkrusher thanks, I upgraded to HD shortly after this video

[@petermclaughlin5121]

@@donyboy73 ii xx iii xx o i ok ifi iii os p ii looks good

[@petermclaughlin5121]

@@donyboy73 ii I od

[@Deadbuck73]

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!

[@hartfordsignpost589]

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

[@petermclaughlin5121]

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

[@donyboy73]

Glad you enjoyed it!

[@231MasseyFerguson]

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!!

[@donyboy73]

@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

[@snickerstorino]

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

[@mikespain8655]

That old tiller is hitting a lick, good job.

[@jimvin3]

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

[@martinc6610]

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

[@pwleppa]

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

[@EnyawtheGreat]

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!

[@Zachry86]

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

[@donyboy73]

check out www.discountonlineparts.com

[@circle2land]

Thanks for the video, I used this as a guide to tuneup a 1984 B & S Snapper lawn mower carb system and clean out the tank.

[@rafaelramos7099]

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.

[@youtitta]

You're a natural. Big thanks from Melbourne Australia

[@donyboy73]

+youtitta greetings from Canada

[@surfinmuso37]

The other Victoria...

[@mandrakethemadcoder]

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.

[@spiavsspia]

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.

[@kwilliams801]

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

[@clare6414]

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

[@donyboy73]

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

[@sindizzy100]

Followed your guide. The mower works great now!

[@geraldrourke5499]

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

[@tramman82mk2]

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!

[@donyboy73]

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

[@donyboy73]

@blitzkriegdaven thanks for watching

[@JP5isalive]

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?

[@johndepetrillo9761]

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

[@kwilliams801]

I finally had to remove the little screen filter in order to clean the fuel dip tube. Is there a good way to cobble together a filter? I am thinking of wrapping a few layers of panty hose around the tip and tying with SS wire. i tested panty hose in a cup of gas and it didnt melt over night. any other better ideas? thnx so much

[@FTGRC]

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

[@timtweet8149]

Have a similar carb. Do you have a link to where I can get the gaskets and diaphragm from? Part numbers would also help. Thanks in advance.

[@ucib4ua]

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.

[@fakepopster]

Great stuff. Is it possible to get the model number off that engine? I have the same machine but cannot read the engine model. Thanks

[@Beerpiglet]

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

[@MsBatMar]

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

[@keihgreen7673]

hi thanks for the video , does the auto choke do away with the need for a primer valve ? I think I may have put the auto diaphragm spring in crooked and still add petrol to the filter to prime, however it's amazing how much better the mower runs after doing what you have shown, just need to check the butter fly valve and correct the spring if needed. what does the other diaphragm do please.

[@donyboy73]

@edwoodsworth you're welcome

[@TaurusWM]

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

[@donyboy73]

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

[@markfewtrell2198]

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?

[@seasonedtoker]

@donyboy73 good thing he mentioned that. I have a question for you, master. how can I convert my ordinary 95902 lawn-mower engine to run without a blade? do I have to convert to iron flywheel? what else then? new crank? thanks a lot!

[@gerardcousineau3200]

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

[@donyboy73]

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

[@csgorton]

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

[@jamesmccleave3322]

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

[@Ataraxia27]

Thanks for this great video. I'm rebuilding the same carb, but had the wrong diaphragm sent to me. Could you tell me the part number of your diaphragm/gasket? thank you!

[@chas1617]

Ataraxia27 I also need the part number of a new diaphragm. Mine had no gasket as others do.

[@Texassince1836]

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

[@donyboy73]

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

[@donyboy73]

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

[@plugger4945]

What does it mean when the starter rope pulls real hard, and/or to at all? Any help, would be appreciated. My aunt probably blew the engine, it didn’t know it.

[@donyboy73]

could be a blown engine but I would have to see it to be sure

[@plugger4945]

@@donyboy73 Thank you for being so kind, and answering. Yes, I agree. I doubt she knew enough to actually check the oil. Too bad , it’s an old MTD, that looks almost new. Shame. On a brighter note; You Sir, are a fountain of information, and obviously, a true gentleman. Their not in abundance these days. Thanks again.

[@canadianweasel]

I've this same tiller with an engine that isn't producing a spark. I've checked the magneto and it's good. The kill switch wiring doesn't look happy, though I'm somewhat a newb about engine repair. Anyway, would you happen to have a repair manual for this puppy? And by puppy I mean the engine because you can't actually repair a puppy, yet you can fix one.

[@donyboy73]

you can replace the diaphragm and maybe try adjusting the carb

[@Gears.and.Gadgets]

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.

[@JosephHua]

@donyboy73 The H screw is it the screw that control the gas for air and fuel mixture or the idle screw?

[@zragevii4705]

Just found one of these and have started to take it apart.... it's been sitting 20 years or more from what I've been told... but, it still turns after removing the fan shroud... any suggestion on where to look for replacement parts for one of these?

[@donyboy73]

www.discountonlineparts.com

[@zragevii4705]

@@donyboy73 thanks, I will definitely check there... 20 or more years, partly buried... oil is still fine...😂

[@donyboy73]

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

[@learner099]

I know it’s a long shot, as this video is eight years old. But I just picked up a mower with the same carb. Where can I get this carb kit?

[@donyboy73]

www.discountonlineparts.com

[@donyboy73]

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

[@ucib4ua]

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.

[@housmass45]

Absoluty a fantastic video on this old B&S 3.5 er ! I have the same carb on my 3.5 B&S mower that I got this year for free ! It runs sort of ! It bogs down under load, or quits ! I suspect it's the governor, how to you fix/adjust this ? HELP ! Many thanks, Ted

[@karnsaini]

Hey dony my Briggs and Stratton 4hp motor suddenly started surging I cleaned the carb but it only helped for a little while I changed the spark plug too but It Dident help so what do you think I should do

[@ucib4ua]

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?

[@rickduyck3583]

Hi you may have posted this but I cannot find anywhere, is there a complete carb kit #? Thanks!!

[@donyboy73]

it will be a diaphragm kit, go to partstree.com with your model number

[@rickduyck3583]

@@donyboy73 thanks!@

[@vetvat]

Donny, I have a similar carb to the one in the video, it starts and runs fine but when I put the throttle lever in the stop position it just carries on running on tick over, any suggestions what the defect might be, cheers

[@donyboy73]

@spiavsspia sounds like the carb needs a good cleaning

[@Krankie_V]

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 :)

[@foreverwood1963]

Dony I'm trying to understand why this suction lift carb has two suction tubes, can you explain that?

[@donyboy73]

@OB1974 thanks

[@donyboy73]

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

[@curtisloewen2545]

Donny I just replaced the carb gasket and noticed when taking the carb apart that the larger diameter spring was located in the gas tank hole and not in the carb hole. I put it back as I found it and the engine works great. Is it possible that the spring actually belongs in the tank hole ?

[@clintonsharp6057]

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!

[@TaurusWM]

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

[@_CryptoNoob_]

I have this same exact tiller. Just rebuilt the carb and replaced the diaphragm. Now the carb will not pull fuel into the combustion chamber. Oring is good in the manifold and the carb is assembled properly. Checked to make sure all the ports and jets are free of dirt or blockages...I am lost. I can pour fuel into the arb and it will run great, but will not pull fuel from the tank on its own. Any help would be greatly appreciated . Thanks

[@seasonedtoker]

@donyboy73 do I need to change the whole crankshaft because of that?

[@TaurusWM]

I can only remove the head x replaced the rings? you have something to suggest, even video? thanks

[@carlosfigueroa1969]

Hi, how are you? I consult you about what type of oil does this engine have? Thank you. Greetings from Argentina.

[@ryanhamilton9709]

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

[@chrisflood646]

I have a tiller very similar to this one with the same engine. I need to change oil and clean the carburetor, but I don't see a drain plug for the oil. Is there one on these models?

[@donyboy73]

@MrDennis8805 thank you sir