Diagnosis of NON STARTING 5HP Briggs Engine

Filmed September 2011
In this video I show you what is causing this 5HP Briggs & Stratton engine to not start.
Visit my channel for more repair videos;
www.youtube.com...
Buy small engine parts here; www.repairclini...

[@CadeIvy]

I dont know if you will see this, but you are the one that taught me to be a mechanic. Fours years later with many mowers repaired and a few of my own, i thank you very, very much!

[@donyboy73]

+Cade Ivy you're welcome!

[@donyboy73]

@Derrick Smiley honda gcv

[@tazman9954]

@@donyboy73 What if there is only one dot on your camshaft and not on the crankshaft and when you pulled out the camshaft both of the pushrods fell out at the same time how do you know which one is which?

[@johnscovel3170]

There is no adjustment down below at the valve you idiot

[@paulzacher5672]

When it comes to engine repair you are still the king

[@williamorton7600]

Thank you Donny. I'm almost done rebuilding an identical 5HP B&S pump engine for my Dad. Your videos on this engine have helped me a ton👍

[@douglasgauthier6428]

DOUG IN MICHIGAN I HAVE LEARNED ALOT BY WATCHING YOUR, VIDEOS I DO THE WORK ON MY SNOWBLOWER MY SELF INSTEAD OF TAKING IT TO A SHOP SAVING ME LOTS OF MONEY THANK YOU FOR SHARING YOUR VIDEOS

[@mowermanone1621]

Dony, I use a leak down tester to pinpoint the wear item. Cost of tester is appx $45 US. Good video. Your videos are always informative and entertaining.

[@RussellBooth1977]

I replaced the rings in my 9 series Briggs & Stratton push mower engine yesterday. Instead of needing 6 pulls to get it as started now it only need 1,my auntie gave it to me in 2008 & it had a broken pull cord in the pull starter, when I fixed it up it took 3 pulls to get it started but then it got worse. It doesn't burn oil under full load like it used to as it used to use 1/3rd of its oil capacity in 1-2 hours of mowing !

[@randi740]

Hi Dony, this summer I tore down the engine on my 1980 Cub Cadet witch has a 17 horse twin kohler and with the heads off and sitting over night I noticed the left cylinder was leaking a-little oil. Time for a ring job but it still runs great. Enjoyed the vid and Happy Thanksgiving to U and your wife.

[@Deadbuck73]

Don never looks awkward to me... He does a great job.! :)

[@donyboy73]

yes i try to repair my own car as much as i can, there are a few choices when it comes to replacing an engine,

[@JD2010whisperer]

Burnt valves and scored cylinders were popular on those I/C engines with Koolbore. The cast iron sleeves and alloy valves solved a lot of these problems.

[@ChargerMiles007]

If you think that is funny, you should read the letter I sent to Briggs about 15 years ago when I built my Monosoupape (single valve) Briggs lawnmower engine. I made it sound like I had discovered an Escapee from their R&D department :) I mailed the letter and 2 photos of it running. A week later a guy from Briggs phoned up, saying it was the funniest letter he had read in 6 months! Then I admitted to him that I had built the engine, not found it at a yard sale. Fun times. Luv your vids!!!

[@donyboy73]

thanks, have a nice evening

[@ChrisMichaelsChicago]

Love all you videos! Here's two words that may fill your life with joy, while simultaneously! A Cordless ratchet that has a pair. ( I won't mention names but mine is from Wisconsin) LOL Any link you can reply that will tell me why this craftsman (briggs 6.75Hp) pressure washer pulls but there's no resistance. the fly turns, the piston moves and it spins over quite a few times per pull but with my finger in the plug hole no air. all I hear is what sounds like air from the exhaust droning on the stroke.. Thanks Dony!

[@marknye51.thefixitguy]

Hello Dony. I am working on a McLand Reel Mower with a Briggs and Stratton Horizontal engine 093302. If you pull the recoil it spins freely and will turn the shaft but will not turn the crank or piston. Flywheel key is intacked . There is zero compression. What is the cause ? Do I have a broken crank or cam release mechanism?

[@donyboy73]

carb and or throttle cable?

[@Bdoodee]

Still the best of the best! Donyboy you always put out great videos. Keep doing what your doing and hopefully the black flies weren’t too bad up in Skoka this year! Cheers!

[@donyboy73]

mosquitoes now

[@Mooseracks]

Here is a dilemma.. I have an older 5 hp Briggs motor which I am not sure what to do. On the compression stroke as the piston starts to travel upward, both valves should be closed...yes/no. ON this engine, the exhaust valve is closed, but the intake valve has leakage up to where the piston travel is 3/4 compression stroke. Valve clearance on intake is at .008 at the recommended pistion/ valve positioning. The engine won't run as it coughs back through carb...and get a puff or two as it wants to start. I could be wrong, but all my understanding of 4 stroke engines tell me that BOTH VALVES SHOULD BE CLOSED ON COMPRESSION STROKE. Any thoughts shared will greatly appreciate.... bern

[@donyboy73]

the coloring may depend on the oil you are using

[@moofushu]

Mr Donyboy I was wondering if you also work on your own car? It looks like many of then things that apply to small engines also apply to large engines. When you go to replace the engine is there a many choices of after market engines or would it have to be that exact engine model?

[@jimbucholtz3552]

Replaced the carburetor on my 5hp Briggs & Stratton roto tiller ( thanks to your instructions) the throttle works wide open but won't return to idle . Why?

[@droidrazor873]

I had that with a snowblower try swapping out the coil. I did that and the engine started and fixed all problems hope that helps you

[@aureliocalderon1184]

Exellent well explained keep up the good work...🙏👍 i just open my motor it was like that burn but the block was intact...now im going to check the valves if they are loose i fighting with this motor for a week..new carburator new spark plug check the coil for spark clean the inside..inside... still looking for the problen😊

[@PeterAgostiniJdcap26]

why was it burning oil ? good vid ! TY Don

[@MannyFontes1968]

Hello Donyboy, first time subscriber to your channel and I have a question. I have a craftsman pressure washer that I hadn't used in a while and when I tried to start it, it wouldn't start unless I used some starting fluid in the spark plug hole. I checked the compression and it was at 30 psi the first time and then added a about .5 ounce of oil in the cylinder and got about 80 psi after pulling it about 5-7 times. Spark is good and the fuel is new after I took the carburetor apart and cleaned it out to include the fuel tank that had some gel like substance in it near the screen at the outlet hole on the bottom. What other things should I check? Also, i removed the pump to make it easier to try and start it. I will take the pump apart and clean it out also.

[@josefranco3971]

Danny, thanks for your videos. I like fixing lawnmowers and have a question. I have a briggs and stratton engine that I removed from a troy built self propelled. It had good spark but wouldn't run even if I squirt starting fluid on carburetor. I also noticed that the carb choke was fully open on cold when I tried to start it. I suspected a governor problem and opened the engine but not sure what to look for. Also when the piston is on TDC, does the coil need to line up with the magnet? I would appreciate a suggestion. Thanks.

[@fixnethin]

Hey dony, I got a question for ya, have you ever run across Wentworth stuff? A buddy of mine got a cpl bsa motorcycles at an auction reciently n brought them to me to check them over and some of the bolts are way different from standard and metric sizes and I can't seem to find many Wentworth socket sets even online

[@SancteAlphonsus]

If you observe that you have a lot of carbon build up through the spark plug hole do you recommend taking the unit apart and wire brushing the piston top off or is there a product (like Seafoam) that will take care of it?

[@pinomarino8917]

Is this the engine you performed the crankshaft swap on?

[@weschaffin]

Question: do i have to replace the head gasket each time i remove it?

[@tudocervera3764]

well explained videos my friend... on my briggs and Stratton 5hp stand up , compression is 90psi,,, checked for spark all good there ,, sprayed starting fluid down the throat ,, no life at all... next step is carb rebuild,, but what baffels me is it should at least run for a few sec, with starter fluid if the carb is bad ,, any tips?

[@KIDZKARTBLDER]

I seen it to next to the exaust valve theres even a little spray on the muffler from the head gasket leak .....good eye man .....I was wating for donyboy to say something about it but he must not have seen it

[@DP-hy4vh]

I fixed a 3hp engine on a rototiller last week that had the exhaust valve stuck in the open position due to a build up of carbon and burnt oil. I finally got it working again by using penetrating oil and gently tapped it back down with a block of wood on top of the valve and hit the wood with a hammer when the valve was supposed to close. Whoever had the tiller last put too much oil in it and was burning oil like crazy.

[@joeboy32666]

I have a 5hp side shaft b&s. It starts fine and runs for about 15mins and the shuts down. If you choke it, it will start and run for about 30 seconds. I'm thinking a coil because I don't know why you would have a fuel problem every time in the the 15 minute range. What do you think?

[@jonny60991]

the cabel is fine .. so dose the carb need to be cleaned and if that dont work replaced ?

[@Junkyard-Restorations]

how much would it cost for you to get that motor running if you had to hone the cylinder etc.?

[@Tristan102100]

have you ever thought of using a battery impact driver for removing hardware? odviously you wouldn't use it to pit the hardware back on but it seems like it would speed up your production. i use one when i take things apart

[@Tristan102100]

i took the head off of a 12 hp briggs(i dunt even remember why) and decided for some reason it would be a good idea to scrape off the carbon. so i put it at top dea center and went away with a chisel and a wire brush. when i was done i put it all the way bottom center and wiped it clean with a microfiber rag to get any carbon that fell down. i also turned it over by hand a few times and kept wiping until there wasn't any more carbon on the cylender. is there a better way to do it?

[@CraigArndt]

Those a bulletproof motors, but like any motor if not maintained this happens. The Briggs and Onans have as part of the maintenance schedule require to remove carbon from the engine. Guess those motors are more prone to it.

[@rwbishop]

Hmmm... I suspect something scored the cylinder wall, and the rings started passing oil in the area; that over a little time 'washed' the carbon spooge 'crescent' shaped clean area from the piston crown. Later, as the scoring progressed, compression diminished to a no run. Would like to know how long it smoked, and to see the piston & rings in the teardown video!

[@rogerbrandt6678]

Hi Danny like your videos, I have a newer jd snowblower, with a snow max engine, I replaced the coil, but after about 3 minutes of running it stalls and then doesn't run no more than 20 seconds? U think the carb could be gummed up as I never used it one whole winter.?

[@acehydro06]

Hey great videos! Have a question for you, I have a marijama backpack blower and cant get it to start it was running fine about 5 months ago and now nothing. I tried putting a little gas in the carb and it fires up and dies so I am thinking its a fuel problem. I took apart carb and checked the lines still no start. I am thinking it might be the diaphram how can u tell if that part is bad or not and what else can it be? Totally stumped at this point any help would be appreciated. Thanks

[@bobbyatman273]

Hey Dony awesome vid! you are golden!, please when you can do a vid on overheated briggs motor with unseated exhaust seat and BENT valve!

[@gokartkid25]

I have the same engine on a go kart. It seems to have not to much compression but it sure does fly . It revs well and hauls. It feels as if it has less than a 1.5 hp push mower engine. Does it mean it has low compression and could get more power if I figure out why or is that normal

[@joshneves1759]

shit, I picked up a roto tiller off the side of the road and it was locked up, I broke free the piston and sanded the rough edges on the cylinder and cleaned the valves, and sanded the head a little and its ran for years, smokes but runs great

[@Budro4764]

I know you have time in that engine> How much did you charge to check it ?

[@donyboy73]

thanks, I say that because I always joke with people that come in, but I find it hard to smile when filming, lol

[@sandydogy]

Hi Donyboy73 could you please tell me when you get carbon build up like this video, what is the best way to remove it? is there any risks with scratching? thanks

[@caillelewis6673]

you can use a soft wire brush lightly with WD-40

[@Zyphen4866]

try some seafoam

[@jonny60991]

great vid dony i got a ? i have a 98 honda trx300 four wheeler and when i start it it rev's high i mean really high and it stick's if i cut it off and back on it's fine .some times it sticks when i ride it and if i go up a gear it wont stick .... someone said it might be the carb ..do you have any idea's .. thanks john

[@mwatkins2464]

You said the large valve is the intake. I always thought the big valve was the exhaust. Are you sure you didn't get that backwards because when you pushed the piston down the small valve did opened to allow the gas to enter!!

[@harrisonp3727]

For an older engine that's still in good running condition, do you recommend using a fuel additive to keep piston top clean or a head disassembly to clean the carbon off mechanically?

[@donyboy73]

no additive, always better to disassemble to clean it

[@IntelGoesHard]

I'm very confused on my B&S 5HP engine. It has lower compression, about 57 PSI from my test (there's no decompression on this engine), but the cylinder wall looks great, the piston looks great, and an unscientific test of the valves seems to show they are sealing. I put my mouth over them while they were closed and tried to blow through them... no leak. My spark is awesome, but it won't fire. My only lead so far is that the head appears to be very warped. I ordered a new head gasket and am going to plane the head to see if that can get it going! I don't want to junk it, it looks mint inside!

[@jonsworld5307]

head gaskets or warped head

[@gregorymalchuk272]

The old brigs engines that didn't have any decompression mechanism still had an extra lump on the exhaust cam that didn't allow the valve to fully seat until maybe 10 degrees before top dead center to make it easy to start. They called it "easyspin". Another cause could be valve seats popping out. They can be shoved back into place and the aluminum peened all around them.

[@Tristan102100]

it may have the same problem as this one. think of it this way, when you pull it slowly, the air has time to excape past the piston, but when you pull it fast, it doesent have time to excape, creating some pressure

[@ltlbeast]

Hello Donyboy, I have an old Mastercraft Snow blower with a briggs motor that wont start. unless I put some fuel into the spark plug hole. I am ordering a rebuild kit , but what else should i look for .??

[@commanderwhite12]

Donboy I need help with two generators i own.. Both are old homelites. (Before they shut down.) When i got bot of them their carbs and gas tanks were off so I didnt know how they go back together...are they supposed to go wide open throttle the second they are fired up even with no load? MY older on isnt producing power and its at wide open throttle..just got it all back together..and the throttle is open..when i try to shut it the spring pulls it back open. Know Im good with motors but generators scare me because I dont want to blow the motors..They mean alot to me and im just trying to save them...They cant go back to the scrap yard..I saved them from there. Can you help?

[@Tristan102100]

the faster you pull the smother it will be. ir it may have a decompression lever. my 250cc atv is the same way,so i just hit the decompression lever and give it a flying pull and it usually starts first or second try.

[@donyboy73]

good one! i like your engines too!

[@skyb8687]

If you're running a compression test on a mower, do u still need w.o.t??

[@PeterAgostiniJdcap26]

Good, I see this as a engineering problem.TY Don

[@donyboy73]

a 4 stroke will be slightly lower, look up compression test on a 4 stroke engine on my channel, thanks for watching

[@donyboy73]

some have a cast iron sleeve ad usually you can hone them

[@donyboy73]

since i can't see it i suggest maybe replacing the carb kit

[@jameshatfield6814]

Dony, how would boring a cylinder and replacing with corresponding rings and piston, not guarantee the engine to run right again?

[@donyboy73]

maybe the carb isn't sealing properly there, i would have to see it

[@fredrickvoncold]

Are most small engines aluminum cylinder were you can't hone them?

[@macknumber9]

Which compression tester do you use/recommend?

[@paulrhodes482]

Thank you for another amazing video! What would be the proper compression reading for this engine? Thank you for all you do to help us newbies I appreciate you very much.

[@donyboy73]

because of internal decompressor you may only 60psi which is normal

[@Deadbuck73]

Serious? No. Sincere yes. Knowledgable ... Much so... Keep up the great work!

[@lcbcreation8205]

I have a engine just like this one was running pretty good but dirty, took it apart cleaned it painted it and going to use it for a drift trike. I have a problem now though. Now that i put it back together. I have no idea what could be wrong, it idles fine but when I give it throttle it breaks up really bad just doesnt sounds right almost like it's out of time... I only have two screws on the carb. Everything seems fine just hates rpms now it will rev up but it sounds bad for the engine. Is it possible for the coil gap to be close enough for idle, but to far apart for high rpms? I had a business card underneath but then one spot seemed to close for comfort even though it didnt scrape. So I put it up a little further seemed like it might be to high but it started and idles so I'm not sure it that's a problem or not. Does take more pulls to start now too I know I screwed somthing up just dont know what. I know the exhaust valve doesnt seat properly on one spot it's a very small leak but it's there but it was there before I took it apart and cleaned everything and it ran pretty good and revved up great for the most part. I did shave the eyebrows but not alot at all didnt damage anything doing that so idk if maybe that still is messing things up somehow? Maybe better flowing air is making the leaking exhaust seat worse? This thing would rev up good and backfire a little before it cant even do that anymore somthing is not right. I need help. Sparkplug was dirty cleaned it off checked gap but even when it was dirty it ran alot better so I'm so confused on what I've done or how to fix it.

[@monopoly-hy6ol]

not sure how to send you an email but I do have a question on craftsman hs50. It leaks oil out of the oil seal on the crank and I am going to order the part but I have also notices that it leaks oil out of the breather. do you know what would cause this? It mainly does it if its on an uneven surface like driving it up on my truck ramps. Also I'm from canada and finding it hard to get parts locally. Where fo you get yours.

[@tomellson5836]

Dony what type of oil do u use for heavy use

[@rgebes222]

If your exhaust valve clearance is too small should your engine still run?

[@dp4867]

Hi Donyboy73, so you say a homeowner snowblower with 5.5 hp should have at least 60 psi compression, what about a crafstman lawnmower with 173cc B&S engine should the compression be??? Thanks, as always a great job.👍

[@donyboy73]

yes about same maybe more, it's a low ready but it's because there's a built in decompressor

[@dp4867]

@@donyboy73 Thanks a lot, much appreciated 👍

[@dp4867]

Hi again, sorry my bad the engine is B&S with 190cc. not 173cc. so i assume the compression is higher.Thx.

[@cobowasepro8531]

Hi! First of all, congrats on your great video guides! If I may, I need to ask you a question: i've noticed there is no cylinder head gasket in this engine, while my Briggs (which is exactly the same model) has one. Is it really necessary to mount this gasket in order to run the engine? Because nobody retails it in my city. Thank you in advance!!!

[@donyboy73]

Cobowasepro yes you need the head gasket, you can buy it online

[@2012isRonPaul]

donyboy73 what if the valves arent moving at all on a B&S lawn mower?:o and would i need to buy a new gasket if the old one kinda broke off while removing the head?

[@skyb8687]

@@2012isRonPaul make one,

[@bigbass122]

great video, I learn something in every vid you put out, thanks. Nice tool box, I have the same one in blue, can you give us a sneak peak at what you have in it. Keep up the great vids.

[@angelorg77]

dony i have a craftsman 21" 6hp brigs & strat push mover thats leaking lots of oil mostly by d pvc tube & drains by d air filter any sugestion on whats wrong so i can buy d right parts ? thanks

[@trancedejectionseat]

Going to throw a few cents in here. In my experience it's for consumers looking to diagnose their own small gas engines. You need the trifecta of compressions, fire, and fuel. If you have spark, and are getting fuel most often indicated by a wet plug then you should look into the compression. Compression is a rather outdated troubleshooting method and with a leak down test you can find out where your loosing your squeeze whether it through the piston/rings or through the valves.

[@donyboy73]

yes it's good to clean it off before it causes damage

[@dipjr.8843]

hi i have a briggs and stratton mowett mustang and it doesn't have spark if you touch the coil boot it will shock you but when it has a plug there is no arch what could this mean? ( i have tried multiple spark plugs all the right one for this mower.)

[@lesterkjohnson9104]

Very informative lesson donnyboy. THANKS

[@donyboy73]

you're welcome, thanks for subscribing

[@msport224]

do i need to clean the top of the piston in my 2 stroke victa mustang? it runs on 25:1 and our section is like over 1/4 acre so the mower gets a good hard use once or twice a month. thanks

[@msport224]

how do i adjust the carburettor on my 2 stroke briggs and stratton lawn mower as it is running quite rich and blowing alot of unburnt fuel and sludge out of the exhaust

[@donyboy73]

if you go to partstree dot co you can find a parts list

[@jati9782]

On my old mower,when I remove carburetor compression stroke is easy like other strokes and when I put carburetor compression is only little bit stronger.So that is probably bad intake valve?

[@julieddie34]

Will a flywheel key cause the briggs and stratton engine not to turn over. It looks like my son jammed something in the blades causing the lawn more to stop. Then it does not turn over anymore seems like it has too much compression. took the spark plugs out and check if it has spark by holding it on the head n the engine turned over but when I put the spark plug back. Engine does not turn over. If the flywheel key does cause this problem do you have a video that shows how to replace it

[@heatherwhitworth9680]

Fly wheels are very easy to replace I replaced mine today in about five minutes on my sons go cart the kit is ten dollars

[@Ryan-uw1hw]

The valves are just out of adjustment.

[@donyboy73]

thanks, yes i have one, in this case i highly suspected something in here

[@DukeofDonaAna]

What kind of compression should one without an auto decompressor read at?

[@jamesstethers8173]

Hi donyboy73 I am trying to figure out what Is wrong with an old Tecumseh engine on an old eager 1 mower by craftsman. I took it apart and the carb and the cylinder look and think the spark has spark

[@brianmott728]

How do you know when you need to do a valve job?

[@retro_88yota]

I have a 5hp engine where the valve seats and the corner of the block warped the block is in buteful shape untell you get to the valves

[@donyboy73]

yes, if you use seafoam make sue the liquid with dissolved carbon does not go into engine

[@turkeyshoot55]

I have a 6.5 Briggs and Stratton engine that will start right away but then when I empty the bag and go back to it it won't start again. I'll let it sit for awhile and it will start again. But it won't start right away after i turn it off. I cleaned the carb, checked the gas, changed the needle and seat also. What is the problem, can you tell me?

[@MrShitrope]

change the coil

[@ajjasper2338]

i had a motor about the same one, i was going for a ride, and i was giving it a good amount of gas but not going nowhere, i let go of the gas, it shutdown, and all this smoke came out of the crankshaft, i tried pulling it, but its locked up. i checked the oil, and there was no oil, just plain dry. any way that i could probably get it back to work?

[@dj5752]

Hi Dony, How can you tell if a unit has an automatic decompress-or ? Thanks John

[@joej.4170]

John Ambrosino all over head valve OHV engines have a decompressor. if not you would not be able to pull the cord, it would be like pulling a 100lb weight.

[@donyboy73]

you're welcome

[@donyboy73]

thanks

[@donyboy73]

not necessarily

[@Owiko7]

hi what was my grandads old tecumseh 5hp snow blower has scratching on one side of the cylinder,i was trying to fix it but i didnt have any cleaning aersol sprays with me. also the carb was completly gummed up, throttle wont move, choke is very sticky.and the exaust is missing its screws. any hope left in this machine?

[@jwotham96]

Well the gasket was the first thing i saw.couldn't see sleeve.noticed the carbon quick to.

[@Tristan102100]

i had exacally the same problem and i replaced the coil it now runs for hours flawlessly but the occational stubborn start

[@TheRCcarDUDE]

my engine has carbon buildup like that but its not scored yet can you just scrap of the carbon ?