1. Briggs And Stratton Classic 3.5 Hp
2. Repairing Valves Briggs And Stratton Classic
3. Briggs And Stratton Classic

Ref: BP795477 B&S complete carburettor assembly suitable for manual primer systems.Used on selected models of 9 and 10 series engines. (Please note that other choices maybe available dependant on the Model, Type and Code number of the engine) if you unsure please check before ordering! Ref: BP498260 Briggs & Stratton Carburettor Overhaul Kit 498260 This is a GENUINE carburetor gasket set for Briggs & Stratton engines. This replaces Briggs & Stratton part numbers 493762 or 498260. Used on models: Briggs & Stratton ENGINE: 12A800 Briggs & Stratton ENGINE: 12D800 Briggs & Stratton ENGINE: 121700 Briggs & Stratton ENGINE: 121800 Briggs & Stratton ENGINE: 122700 Briggs & Stratton ENGINE: 126700 Briggs & Stratton ENGINE: 126800 Briggs & Stratton ENGINE: 127800 Briggs & Stratton ENGINE: 128700 Briggs & Stratton ENGINE: 128800 Briggs & Stratton ENGINE: 129700 Briggs & Stratton ENGINE: 129800 Briggs & Stratton ENGINE: 133400 Briggs & Stratton ENGINE: 83400 Briggs & Stratton ENGINE: 90700 Briggs & Stratton ENGINE: 99700. Ref: BP591420 Briggs & Stratton Ignition Coil & Magneto Armature.

Check this is the right one BEFORE ordering Supersedes 298502, 697036, 792395, 496914, 398593, 793281, 793352 Replaces Part Numbers Briggs and Stratton 395488, 298502, 697036, 496914, 793281, 591420 OEM Numbers: 395488, 298502, 697036, 496914, 793281, 591420 Type: Ignition Coil Description: Ignition Coil Replaces Briggs & Stratton 793281 Replaces Briggs & Stratton 395488, 298502, 697036, 496914, 793281, 591420 Fits models 60000, 61000, 80200, 81000, 82500, 82900, 92500, 92900 & 111000. (2, 3, 3-1/2 and 4 hp horz.

& vert.) For Older Briggs Engines with Breaker Points. Ref: BP791766 Briggs and Stratton 791766 Pre-Cut Fuel Line & Clamps Kit. Genuine Briggs and Stratton replacement parts guarantee durability & performance. Replaces previous part numbers: 298049, 691050. Check description and parts illustrated diagrams to ensure the part is a suitable replacement. Exact fit genuine parts are designed specifically for Briggs and Stratton products. Fitting original parts helps maintain manufacturer's warranty requirements.

38cm or 15' Length. 1/4' or 7.5mm I.D. 1/2' or 13mm O.D. Supplied with two 13mm clamps.

Sun 3 Jul 2005 11:45 Briggs & Stratton mower sooty - smokie This mower is under 3 years old and is clean with very low mileage (small garden!). I was away last w/e and Mrs S said it felt like it was running short of fuel - it starts to rev itself when it is. (The engine runs at same revs whether clutch is engaged or not). So she filled with unleaded from our usual can - not dirty. The mower now idles and runs roughly, with black puffs of smoke from exhaust, and the plug is wet sooty. I'm assuming this is rich mixture. I've taken off the air filter which is not clogged and it runs the same without it so I don't think clogged air filter is the cause.

It seems to run OK for the first 30 seconds then go into this lumpy mode. I'm wondering if the fuel supply is restricted (dirty maybe), but can't see how to get at it without going beyond my scope. I hear that putting it in for a service will cost half the original cost of the mower.! Any quick hints or tips please? Mods - please feel free to move this to IHAQ is that is the right place.

Sun 3 Jul 2005 12:22 Briggs & Stratton mower sooty - mfarrow Stupid question: is the choke still on? Check that it's coming off OK.

After checking this and the air filter, I'd be surprised if it's still running rich unless you've fiddled with some adjuster screws. Revving by itself is in common with the governor trying to keep up with bubbly fuel.

A wild guess: Could this be an ignition problem/misfiring? Check the points and plug gap and readjust if necessary.

Clean ignition points if they're dirty/oily. Mike Farrow. Sun 3 Jul 2005 15:55 Briggs & Stratton mower sooty - smokie Thanks - the engine is compact but also well covered and there seem to be no adjuster screws to fiddle with, and the instructions do not give an exploded view of the engine. There is no manual choke, just a priming button. But that would be consistent I imagine so I will try to work out how the choke wirks (if there is one!). The plug gap looked a bit big but I couldn't find my feelers to check it properly. This will now wait until next weekend, but I will feed back as usual.

Sun 3 Jul 2005 19:11 Briggs & Stratton mower sooty - smokie I had the spark plug out and it was damp sooty. I cleaned it and tried again but it was the same, and was damp sooty again when I took it out. It's larger than most car plugs btw. The fuel (unleaded) could be from last year!! I don't remember getting any this year, in which acse it's been in a plastic fuel can in the shed all winter. The oil (Mobil 1, what else?) is clean as the day it was put in. I considered draining the tank but couldn't see an easy way to do it, without lying the thing on it's side.

Sun 3 Jul 2005 21:21 Briggs & Stratton mower sooty - keo-the-dog do not tip a briggs engine it allows oil to get into something or other it shouldn't. Also does it have the small tank at the side of the engine with small pinholes on the screwtop do not fill these right up as apparently it causes them to run rich and smoke. I am no expert on these but was chatting to an old bloke no more than two weeks ago, when i purchased a second hand briggs engined mower from him.

Taught me a lot in about twenty minutes. Oh and if you have to tip it, you should only tip it forward towards the plug or if to one side always to the side away from the carb.cheers.keo ps. The mower i bought is several years old but starts and runs like a new one.£20. Mon 4 Jul 2005 10:22 Briggs & Stratton mower sooty - Galaxy The chap I work with tells me that his mower will only run properly on genuine leaded 4 star petrol, on unleaded it runs very badly indeed. I recently bought him some 4 star at one of the special garages near me who still sell it. That should keep him going for a couple of years!

I don't know why there is this difference. Perhaps it's because the 4 star has a higher octane rating than the unleaded. If this is the case then, perhaps, running the mower on Optimax or similar might cure the problem, but my friend hasn't tried this yet. Mon 4 Jul 2005 15:28 Briggs & Stratton mower sooty - jacks Smokie I had exactly the same problem with my B&S lawnmower a couple of weeks ago, identical symptoms (starts ok, then runs rough, engine hunting,smoking,) - tried fresh fuel, new plug etc, then phoned local repair shop who told me over the phone the likely problem.the diaphragm in the carburretor had split.

The guy replaced the part (£4.50) + £30 labour. It's probably easy to DIY but didn't want to deprive him of the job as he was so helpful! He indicated it was a common problem so most likely this will be the problem on yours. Mon 4 Jul 2005 23:25 Briggs & Stratton mower sooty - Mikey Jay Is your B&S a 3.5 hp engine? It should have an adjustment screw on the carb if it is.

I know this wont solve your problem but although your engine oil may look as clean as the day it went in when checked on the dipstick, it can be quite dirty when you drain it. You should change it each season. Also do not tip the mower on its side with the aircleaner at the lowest position. I would go along with the suggestions above re draining old petrol out.In warm weather I give it less priming to sart from cold. My engine is 10 yrs old and still on the original champion plug.

Tue 5 Jul 2005 20:29 Briggs & Stratton mower sooty - Cliff Pope Tipping, eg to clear clogged grass from the blade and body, should be towards the carburettor. If you tip it the other way it fills the silencer with oil - you will recognise the symptoms by the dense clouds of blue smoke, when you eventually get it to start again! Most B & S I have seen - I have several in various mowers and rotavators, have an automatic choke flap working by suction. It is a pivotted plastic disc just underneath the air intake, shaped so that the air cleaner bolt clears it down a groove.

If this gets clogged, eg by grass or the air cleaner bolt not in straight, then the flap doesn't open fully when the engine fires. Sun 10 Jul 2005 16:26 Briggs & Stratton mower sooty - smokie Update: I've changed the petrol and cleaned and reset the plug. It runs a lot smoother, except it seems to be lower on power (i.e. Moves slower) than I remember it. I also still have exhaust smoke, whcih I don't recall seeing before.

I'm going to get a new plug next. I browsed the B&S web site and had a long hard look at the engine.

I don't believe there is any (useful) adjustment I could make to the carb but I don't mind being proved wrong. There is no manual choke and I can't see any adjustment screws - and the manual for teh engine says 'choke - if fitted' which I guess must mean some engines don't have them. There is a primer button for starting.

Sun 10 Jul 2005 21:16 Briggs & Stratton mower sooty - mfarrow Glad you got it fixed. Our mower which had problems starting recently (see IHAQ) has never needed the choke. The primer button should be sufficient just to flood the jet for starting from cold.

Briggs And Stratton Classic 3.5 Hp

Re it being down on power. It should run at a constant speed, as you say, adjusted by the governor. By down on power, do you mean that the engine speed reduces significantly now when you take up drive? If not it's probably just your perception, or the governor's mean (mal)adjusted, unlikely if you haven't touched it. Mike Farrow. Mon 25 Jul 2005 11:04 Briggs & Stratton mower sooty - John F If runs ok for few secs then runs rich, clearly carb prob. I had similar prob in a Villiers mower engine - cause was the small brass valve which the float pushes up to regulate amount of petrol entering the float chamber.

years ago I lost it while cleaning carb and had made another out of a brass screw which never fitted very well. You probably had a bit of grit causing overfilling and rough running. The test is to turn the petrol off.

Rough running will eventually return to normal as the mixture weakens, then rev slightly faster briefly, then die as the petrol runs out. Incidentally, all four of my mowers, average age 30yrs, run better on bog standard unleaded. Use old engine oil after 10,000m - still perfectly ok for old mower engines. Suggest filter your old petrol with paper coffee filter.

Recently I found a firm which does spares for ancient mower engines. It's called 'Meetens' - tel 0845 634 0295. Happy tinkering! Wed 27 Jul 2005 11:00 Briggs & Stratton mower sooty - John F Plug unlikely to cause prob - mine are as old as the mowers! Sometimes the HT lead can need a bit of a trim at the hot end after 10yrs if the spark not getting thru and the points are ok. Definitely sounds like a carburettor problem but I don't know anything about 'diaphragms' apart from when found in fuel pumps, which none of my mowers have - all gravity fed. If it's newish I would take the carburettor to bits, clean carefully, reassemble - and see what happens!

If it's black smoky not blue smoky it must be running rich and there aren't too many causes of that. Wed 27 Jul 2005 13:39 Briggs & Stratton mower sooty - Cliff Pope If it's the diaphram I am thinking of then it's actually a simple fuel pump. The petrol tank is underneath the carburettor, and the fuel is pumped by some kind of process that uses the induction pressure - 'sucked' in short. That is why priming is necessary to start the process. It is a straightforward job, but I have to say when I replaced one once it didn't make the slightest difference. I just replaced the whole carburettor from a scrap mower. Wed 27 Jul 2005 17:32 Briggs & Stratton mower sooty - mfarrow The part costs c £9.

Repairing Valves Briggs And Stratton Classic

Am I going to get in a mess if I try doing it myself? For what he's charging it may be a pig of a job, but it sounds like only a couple of hours work, if that.

There's no harm trying and then taking it to him if you hit any problems. As mentioned, plugs don't really cause problems, our mowers still on it's original after 30 years. Cliff, would the priming button also serve mainly as a cold start 'tickler' since there is no choke?

- Mike Farrow. Wed 27 Jul 2005 20:04 Briggs & Stratton mower sooty - Cliff Pope Cliff, would the priming button also serve mainly as a cold start 'tickler' since there is no choke? That's my understanding of how it works. I think they are really pretty crude engines with rather imprecise fuel measuring systems. Even ones I have had with manual chokes only needed the choke for the first few seconds of running.

I think the primer just sloshes in some petrol, it splutters into life, and after that manages to draw the petrol it needs in vaguely the right sort of mixture. The 'automatic' flap (choke?) I most commonly observe is just spring-loaded. When the engine is spun on the cord it is like putting your hand over the intake, enriching the mixture (old dodge for cold weather starting). As soon as the engine fires the suction opens the flap again. I may be wrong, and a B & S spokesman is going to claim that they are masterpieces of precision fueling and that their exhausts are cleaner than the air that went in. But I have read somewhere that mowers and their relatives are actually quite a significant source of pollution, but their engine size makes them unsuitable, or uneconomic, for fuel injection. You can't really go wrong taking a carburettor to pieces and cleaning it out, unless you are hoping to reuse any of the gaskets and diaphrams.

They tend to weld themselves to the castings, and come to pieces when opened up. A thin sharp knife sometimes prises them off intact. Wed 27 Jul 2005 22:29 Briggs & Stratton mower sooty - Colonel Panic I had this problem with my B&S Classic 5, after fuel, additive etc. I removed the carb (plastic it was too) and the very thin diagphram which acts as the pulsejet pump had shriveled a bit causing the mixure to be all over the place.

A new one was £2.50 from Henton and Chattel in Nottingham, put on and it's never run so lovely! The person who said that Mobil 1 is too good as the mower never gets hot enough is totally wrong!

It's an aircooled engine and runs much hotter than a car engine! Thu 28 Jul 2005 13:32 Briggs & Stratton mower sooty - frostbite Ah, reminds me of the time I tried to stop a lawnmower by pulling off the spark plug cable. Took a firm grip on some black rubbery stuff to brace myself and grabbed the plug. Turns out the black rubbery stuff was oil drenched metal.;-) Rest should be self explanatory. Did a very similar thing myself - mower wouldn't start - thinking perhaps flooded or no spark?

Removed plug, reconnected lead, swung engine - fuel gushed out over mower body, ignited by spark plug - still has fried paint + curly plastic badge. Only in the BR would a thread on this keep going so long!

Thu 28 Jul 2005 09:09 Briggs & Stratton mower sooty - quizman I had this problem with my B&S Classic 5, after fuel, additive etc. I removed the carb (plastic it was too) and the very thin diagphram which acts as the pulsejet pump had shriveled a bit causing the mixure to be all over the place. A new one was £2.50 from Henton and Chattel in Nottingham, put on and it's never run so lovely! The person who said that Mobil 1 is too good as the mower never gets hot enough is totally wrong! It's an aircooled engine and runs much hotter than a car engine!

If you don't believe me that Mobil 1 is too good for a lawnmower, go to a mower shop and look at the spec of the specialist mower oil. I think it is SD or SF. I was told by a mower repairer to use 'cheap' oil. Tue 13 May 2008 20:52 Briggs & Stratton mower sooty - Timnbd Oh Joy! Thanks quizman. Smokie described the fault with my B&S exactly, and your suggestion ws spot on.

In fact the thin diaphragm had not split, but had become slightly rucked near one of the retaining bolts. All I had to do was straighten it out and make sure it was laid well flat before clamping the carb back together. Thanks - now runs like new. P.S My three year old mower has been abused with two-stroke oil, overfilled with oil and tipped up the wrong way to empty excess oil out. I have even had to syphon out water from the petrol tank on ocassions and it still runs perfectly well on unleaded! Wed 14 May 2008 09:19 Briggs & Stratton mower sooty - L'escargot He said it's probably the diaphragm I had a problem with the carburettor diaphragm on our Briggs and Stratton-engined Mountfield after only a few weeks of use.

The service agent said it's a common occurence for the diaphragm to pull out from one or more of its clamping lands, and that even some brand new mowers need a new diaphragm. Having looked at the old diaphragm I'm sure he's right the clamping lands are miniscule and I can well imagine the adjacent metal parts not mating up correctly in places. I think it's probably the result of computer aided design which allows small details to be magnified and for the designer to lose his sense of proportion assuming he had one in the first place. It was much more difficult to draw details too small in the days of drawing boards and pencils. Edited by L'escargot on at 09:21. Tue 20 May 2008 19:07 Briggs & Stratton mower sooty - John F Briggs and Strattons just keep chugging along.

Hands up anyone who has actually changed their oil in the meantime? Yes - was knocking a lot - 5hp on Ransome Hahn rideon bought second hand 1979, was ancient even then - took head off - piston had such a thick layer of carbon it was hitting the head! Wouldn't start well, changed original plug, refilled with usual oil from 10,000m car change left to stand for several weeks.now works perfectly again. This is the first attention it has had since 1979.

If it works, don't mend it. Fri 27 Jun 2008 18:54 Briggs & Stratton mower sooty - mickleplum Have a few hayter pedestrians of various ages used commercially and as a rule the older the engine the better it is. Watch for the ceramic inlet manifolds on the later models that develop cracks that also cause running problems. Have a Hayter Ranger that is 11 months old and here we go, starts will run forever and a day and then when you stop it and go to re start no play or takes an age to get going again. Heavily sooted plug with a lumpy running.

So looks like the diaphram proble as described. Have a spy at this site I found for briggs bits which may be a help to you guys. Fri 16 May 2008 20:14 Briggs & Stratton mower sooty - Steptoe My grateful thanks to smokie, and all who replied suggesting the diaphragm might be at fault. On Monday, my mower which is about 13 years old and well past its use-by date, started to run badly, stalling, stopping, etc. On Tuesday I went to check up on the current prices of new ones but happily Timnbd resurrected this thread just in time before I parted with the cash.

I purchased a diaphragm kit today for £3.50, fitted it this afternoon and, mercifully, the mower is not just restored to health but running better than it has done for a long time. My grateful thanks and a virtual pint to all concerned, as befits my username I prefer to make do and mend rather than buy new. Thu 21 Apr 2011 21:08 Briggs & Stratton mower - Push it I have a problem with my 46s in that it is now sluggish so I took the air filter off and cleaned it, but I noticed that the springs on the carb (I think where you adjust the speed) aren't connected properly as the do nothing. If I move the (choke?) arm in the frony of the carb where the springs are attached nothing happens, and where they attach to an arm that goes up and around (about 3 inches) the fly wheel at the top, if you move that it builds the revs up. Does anyone know how thes springs shpuld attach and how I can alter the speed of the engine which I can do when the air filter is removed but not when it is on.Thanks.

Briggs And Stratton Classic

Sat 23 Jul 2016 16:05 Briggs & Stratton mower sooty - Carl James I have a Briggs sprint 375, older model with auto-choke, no primer, and it stops after 5 mins. Tested Everything: replaced the whole carb (cheaper than the diaphram), followed the service manual meticulously and pre-loaded the diaphram at mount.

(On auto-choke models, the adjustment needle-valve have limited function.) Replaced the coil assy. With spark-plug, although it sparked directly after it stopped. Checked breather with feeler gauge, checked compression for loose valve inserts. Always start on the first pull, Always stop at load or 5 mins. Will not start manually, if started with pneumatic driver it backfires heavily.

I simply don´t now what else to do. Sun 31 Jul 2016 01:32 Briggs & Stratton mower sooty - Morris Marina 1.3 Super The exhaust valve has probably sunk/or eroded and once the valve stem has expanded it's held off it's seat.the tappet clearance should be around 0.15mm cold on the sidevalves. Most B & S I see have burnt valves and almost zero exhaust valve clearance and are transformed by a good decoke and valve grinding. It's easy enough to reface the valves with a cordless drill and small valve grinding tool if you have something to grind the valve stem to re-set the clearance. The spring collets are quite fiddly to remove but all you need is a pair of pliers a screwdriver and lots of patience!

Sat 6 Aug 2016 12:15 Briggs & Stratton mower sooty - Carl James Thank you very much for your advice, I have checked the flywheel key for shearing damage, both the valve inserts (Lapped the valves when I had them deassembled anyway), filed the intake stem slightly in order to reduce backfire into the carb, which increased output power a lot, still the problem persisted. But, when I decreased the spring tension under the diaphram, the choke-plate stopped closing and the engine would start directly after it stopped. It still stops as previosly stated and and I have the tank fully fueled and open.