OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Maybe a Carby issue?

Hi guys,

I have never done anything to engines other than an external clean but am comfortable with following guidance on trying to fix things.

Basic symptom - engine won't start/kick over on my groomer. Of course I found this out after I had a ton of sand in my driveway! It's a B&S 3hp 091212-1025-E1 and I've now got the parts and operations manuals from B&S.

I recall @Bonnar_Bloke mentioning something about diaphragms in carbys becoming stretched - is this what mine has done? Spark is present.

My mower is also a B&S but the 475 model 093312-1155-B1 and it wouldn't rev up. Talking to the metal work boys here they explained the bowl and how it all works and I was able to clear the jet and get it back to normal.

All advice greatly appreciated.

Cheers,
TC.

Will it start with a prime of petrol or spray of "Easy start"?

Thanks for the quick reply - I didn't even think to try.. Will do tonight. Is carb cleaner the same as easy start?

TC.

Hi TheCount

That diaphram is cacked, if there are no blockages most likely the issue.

No. Carby clean is for degreasing and doesn't have the energy of petrol or the ether based sprays. Carby clean won't work.

No. Carby clean is for degreasing and doesn't have the energy of petrol or the ether based sprays. Carby clean won't work.

Thanks sparker - 1 can of Start ya B' is on the shopping list as I'm sure its handy to have around.

Thanks wce - it just didn't look right and I appreciate your time. 1 x diaphragm added to cart..

Cheers,
TC.

Wce is right, diaphragm is cactus. Be advised there are 2 different model diaphragms very close to the same shape, so definitely take it with you to the shop

One other thing that can get you with these is the 'bowl' in the top of the tank (especially if it sits for long periods even without E10.

I had one (and a friend had one around the same time), would run at flat stick alright but would not idle. Turned out it pumped enough to keep the fuel level up at flat out, but at idle it drained away and starved it.

Thanks Tyler - I'll do some online shopping at Outdoorking tonight as I'll replace the filters and air-gaskets on both machines too. Appreciate the tip about the bowl in the tank - even running 98 I'll give it a start more often..

Cheers,
TC.

You will need diaphragm pn 272538S. Two different carb to tank mounting gaskets so date code is needed but it looks like it is probably the 692241. Hopefully you don't the 3 quart or 1 quart fuel tank as they are NLA now. Just that fuel well does rust out making a new to the engine tank necessary.

I have seen a couple carburetors that inhaled so much rust that the carburetor internal passages to clogged solidly which is very hard to clean out.

Thanks AVB, the fuel tank is OK with no obvious bubbles or pitting that I can see. The diaphragm is the code I ordered and I’m looking forward to a healthy running engine once again..

The mower engine gave me some grief again today in that it would only run on full chime. Most obvious thing to me is the pin seal not intact... I’ll grab one of those this week and if that still doesn’t correct the issue, It’ll just be a new engine as they’re only $300 and I don’t want to keep buying parts to an old engine.

Thanks for your help mate,

TC.

Need to re-open this query with regards the carb to tank gasket as the engine starts and runs when sprayed or fuel is added directly, and then dies.....

When putting the unit back together, that 692241 gasket disintegrated into pieces and my question:- is it there to form an airtight seal between the tank and carb so that it can "suck up" the fuel? I'm thinking 'no' only because of fluid dynamics where the head/opening of the tube is fully submersed in fuel, therefore no 'air-gap' to impede suction.

As much of an experiment than anything else I created a gasket just so I could "put it back together" but the material is not air or fluid tight.. I'll have another good look at the pickup tube to see if that's also clogged..

Somehow I've managed to remove the jet (#691250) from the carb - does it go back in where I've marked on the image?

My mower carb went well, thanks to the tips above.

Cheers,
TC.

The carb to tank gasket is there only to prevent leaks. Fuel is pickup via the pickup tube and transferred to the fuel well in the tank. This done with the diaphragm on the side of the carburetor using the vacuum of the intake.

Depending how rusty the tank is as to what might be clogged. In some worst cases I have seen the carburetor tower to have internal rust clogs. But usually the idle jet clogs and the pickup tube. One thing to also check is that the fuel well is in tack and don't have pin holes.

If the tower is clogged you can if you are good remove the steel ball at the bottom and clean out that passage. Just remember to replace this ball with something. Here I use a slightly large larger chrome ball.

And the idle restrictor jet goes in where you marked. Just make sure it is clear of obstructions. It has a pin hole that likes to clog.

Just a side note Briggs has stop making the 3 quart tank last year so they are getting rare to find new. I got one left here as I ordered two before they quit. So hopefully you got the 1 or 2 quart version.

Hey AVB,
so you think the old vertical pull Briggs are a better motor than their successors? Do you think Briggs lost their way in a big way before bankruptcy hit?

Thanks AVB,

The way I'm reading is the "platform/well" I can see inside the fuel tank where the pick-up tube sits, and needs to be checked for any degradation and is fuel retained in there.. So is the fuel actually sucked up from the tank via the carb screen and sent to the well to then be sucked up into the engine via the tower? By the manual diagrams I believe I have the 1 quart tank.

I'll work on it again tonight and concentrate on the pick-up area as the engine starts and runs for 15 seconds and then it sounds like it starves for fuel..

Really appreciate your help - great to learn more of the things I knew nothing about..

Cheers,
TC.

MF,
I believe the old Briggs vertical pull motor was a much better motor than the later ones but old man time is catching up on them

NormK they are Briggs Victa full crank. They will easily outlast a flathead Briggs 20 years younger.
They're only thrown out because of difficult starting from a slightly clogged carby which a retrofitted primer carby would overcome which ignorant owners don't realise.

MF, they have nothing to do with Victa, it is just Victa bought them to fit on their mowers, plenty of other manufacturers also bought them. They were a good solid motor and if they had been fitted originally with a primer as you said then many would be still being used to this day. Can't really blame the owners, they are not to know inner secrets like that.

I meant as in Briggs equivalent of the Victa full crank two stroke in as far as being looked back on and venerated.
Yes I was being a bit of a troll when I said about ignorant owners giving up on them.

I just did one today - 1987 Victa Commando vertical pull with snorkel. I have kept the pulsajet as I do prefer them when I can get them running.

Goes perfect now