I agree with Rivets, a good cleaning and replace pump diaphragm
Briggs and Stratton 5 hp (Model 130902) Jet Pulse carburetor problems... Any ideas?
- Thread starter balooba
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Its Me
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balooba, worked on them for years they are the best carburetor and are trouble free most of the time, just clean it and, pull the main jet them took inside where the jet come from and remove the insert ,it is brass the, the rubber pulses and picks up gas through the long up the gas in puts it in the small well and the piston suction pulls the gas into the engine, for a smooth and great running a trick is to get a 12" file put it in the vise, take the rectangular plate that covers the diaphragm and push it along the file length wise, make on or two passes them look at the cover you will be surprised how warped it is, run it down the file until all the warp is gone, it will run perfect, I loved working on those old engines, be a mechanic fix it don't be a parts changer, there is not much satisfaction in being a parts changer, Joe
The Maintenance Guy
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If it's one of those all plastic things, just replace it. They're cheap enough.
first pull
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Pretty much the given for any one of these that doesn't run properly is to remove the tank and take the carburetor off the gas tank, get the tank empty and all the crap out of it cuz they will be plenty, then put a new gasket and diaphragm between the carb and the gas tank.
That fixes the problems 95% of the time.
There is a jet underneath the screen like sock that you can slightly rotate and pull off and then pop out the plastic jet tube with a small screwdriver then you can run wires through these and blow them out and everything else but most the time that's really not necessary.
More than likely the reason this one wasn't running in the first place on its own is because the diaphragm and the spring action wasn't sucking a fuel up to pump it and that whole pulsa fashion.
With the screw out at least at the tank's pretty full, it gets enough fuel and sucks a little bit up there to stay running at least somewhat.
That diaphragm always gets brittle and and stiff over the years and just won't flex like it should..
These were great Little engines back in the day and this style with the primer bulb is much better than the older styles with the chokes or the autochoke etc and I kind of liked them back then because they were more forgiving than the the tecumseh with the float bowl carburetor which often had to be cleaned out every year to make it run right but honestly, today, I would rather have the next upgraded Briggs & Stratton with the float bowl carburetor.
They just seem to be much longer lived and they're built a little bit better and they have a little more horsepower too. Parts are so readily available and cheap.
BTW you don't have to buy the Briggs & Stratton brand for that diaphragm and gasket. Several aftermarket companies make them and they are even available at O'Reilly Auto Parts in advance Auto Parts hanging up in a little blister pack with their lawn mower stuff or sometimes it's in the back but they do carry it however I can't recommend buying it from them now!
It used to be under $4 and all was right with the world but now it's almost 9.00 so I will never buy another one from them.
I can get a five pack on eBay for that kind of money.
Places are going to realize, at least when dealing with me, that when you push that hard ...I'm gone.
I might give you a dollar more for it then I can get it online just because I want to have its day but the older I get the more patient I have become and I will wait for anything to say 50 cents.
That fixes the problems 95% of the time.
There is a jet underneath the screen like sock that you can slightly rotate and pull off and then pop out the plastic jet tube with a small screwdriver then you can run wires through these and blow them out and everything else but most the time that's really not necessary.
More than likely the reason this one wasn't running in the first place on its own is because the diaphragm and the spring action wasn't sucking a fuel up to pump it and that whole pulsa fashion.
With the screw out at least at the tank's pretty full, it gets enough fuel and sucks a little bit up there to stay running at least somewhat.
That diaphragm always gets brittle and and stiff over the years and just won't flex like it should..
These were great Little engines back in the day and this style with the primer bulb is much better than the older styles with the chokes or the autochoke etc and I kind of liked them back then because they were more forgiving than the the tecumseh with the float bowl carburetor which often had to be cleaned out every year to make it run right but honestly, today, I would rather have the next upgraded Briggs & Stratton with the float bowl carburetor.
They just seem to be much longer lived and they're built a little bit better and they have a little more horsepower too. Parts are so readily available and cheap.
BTW you don't have to buy the Briggs & Stratton brand for that diaphragm and gasket. Several aftermarket companies make them and they are even available at O'Reilly Auto Parts in advance Auto Parts hanging up in a little blister pack with their lawn mower stuff or sometimes it's in the back but they do carry it however I can't recommend buying it from them now!
It used to be under $4 and all was right with the world but now it's almost 9.00 so I will never buy another one from them.
I can get a five pack on eBay for that kind of money.
Places are going to realize, at least when dealing with me, that when you push that hard ...I'm gone.
I might give you a dollar more for it then I can get it online just because I want to have its day but the older I get the more patient I have become and I will wait for anything to say 50 cents.
You might check to make sure a good gasket is in place. If there’s no gasket, a poor seal will cause a problem. If there is a thin old gasket, try adding a thicker one to raise the air filter as well as improving the seal.
I've never seen one of those gaskets make a bit of difference in the way one of these things runs. It's only there to prevent some dirt from bypass the filter but even that's kind of a moot point on one of these with its foam filter etc.
People run these things for decades without even having an air filter on them and they run just fine.
I have an old Briggs with a vacuum ("automatic") choke. Briggs had some great ideas but the vacuum choke wasn't one. On my engine, the air cleaner screw is the stop for the choke. Without it, the choke butterfly goes over-center and becomes a choke again. If yours is designed like that, it would indicate that your engine runs very lean and needs the choke to run. Long story short, as many others have said, clean and rebuild the carb.
Helvehammer
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Egads no exaggeration I must have a couple thousand 130902-repairs under my belt 1971-2009. Pretty sure you have the problem backwards - the only fuel it is getting is through the not-metered fuel leaking through the AF screw hole - put the screw in and no fuel at all and it dies.
If you can get a copy of the BS Repair instructions dated 1963 - just follow them in scope and detail.
Probably you can't even on Ebay so I will take it from the top:
Make sure carb throttle blade and choke are open and the spark plug is in it. Snug down the three head bolts surrounding the exhaust valve. Remove the fan housing and recoil starter. put the spark plug wire in the provided V-safety-notch. watch your fingers while you flip the flywheel backwards and it should bounce off compression and go forward a little bit. This duplicates the power stroke of the engine. It is a form of leakdown test. The reason you can't do the same test going forward is the Easy Spin automatic compression release cracks the intake valve open about .010" beginning about an inch before TDC on the compression stroke. The intake shuts completely right before the mag fires. Cam timing one gear tooth off screws this up - it's got to be on the marks.
If it bounces real good you can get fancy and turn it very slowly backwards and listen to the exhaust outlet, carb inlet and head gasket. The piston rings normally leak a very small amount - that's fine.
Okay pull the plug out and figure out how to hold the end of the wire 5mm/.200" off the cyl head anywhere (paint doesnt matter) and spin it over with a drill at least 150 rpm and it should snap a spark (forget color) every single time for at least a couple hundred revolutions. It if ever misses any = fix it (new points usually). Reassemble it all like you are going to run it with a brand new non-Champion, non-China spark plug gapped .030"
Remove every bit of fuel out of the carb and tank. Every last drop, not even moist = DRY.
Make sure it's full-to-overflowing with clean SAE 30 heavy duty motor oil. The ultimate best is Aeroshell "Oil W" SAE 30 (Aviation Grade 60) bar none. Your engine has aluminum cylinder walls which love to score and wad up on the rings - if yours passed leakdown it doesn't have that. It's important because IT IS GOING TO RUN.
Bolt clamp the thing down to something solid. Get a little 2-cycle plastic bottle in the 8-20oz size range that has a good cap. Clean it out good and fill it with 32-1 (or thereabouts) FRESH Two-cycle fuel-oil mix. 50-1 won't work. Richer than about 16-1 is hard on spark plugs. Poke a 1/16" hole in the lid from inside going out with an icepick or something. Don't drill it.
You bolt it down because 1) You are going to set the governed speed to max without any choking action.It has to stay set at that point. Use a stiff throttle control or something.
2) You are going to squirt less than a tablespoon of fuel in the carb throat then set bottle down.
3) Get two fingers on the actual throttle butterfly shaft and be prepared to take control of it either to keep it from overspeeding past 3600 rpm or to keep it from slamming shut onto the idle stop screw (the governors on these things are flaky - letting overspeed even once will throw the governor weights off an tangle around inside the engine)
4) Stroke the rope once good it will start and should govern itself if you let go the throttle.
5) Soon as you can after you crank it grab up the squirt bottle and give it another little squirt, then another - then finally try to keep it running with a steady tiny stream of fuel.
6)Now try and slow it down with the throttle while keeping it running with a tiny tiny stream of fuel. It's a lot easier if you make the gas cap hole so small you have to squeeze hard to make it run full speed. Really about 1/32nd hole is best for this whole test. The reason to do this is to bypass the usually-leaky crummy carb-block gasket and the carburetor's fuel metering ability. Think of it as the final test to establish "if this thing got the right amount of fuel and had no induction air leaks - then it really would run right."
It's getting late - I will go into how to force one these crummy "no fuel emulsion air bleed" carbs to work right tomorrow night. But you are going see if all that is necessary next...
7) Get an RELIABLE assistant to help you for the next part.
8) Start it as before, get it running under direct control of the throttle while bottle feeding it, make it run at an idle (WITH THE AIR FILTER SCREW IN IT) and have your assistant begin adding fuel to the tank in the safest possible way. HAVE A CO2 FIRE BOTTLE OR TWO RIGHT NEXT TO BOTH OF YOU. If you get it to pick up fuel (so that you can quit squirting fuel in it and it runs by itself with the jet open 2.5 turns) but the tank has to be all the way full-to-overflowing for that to happen it means that at least the small fuel pickup is clear and the carb-to-block gasket isn't leaking air real badly. It also means that the problem is with the system that normally fills the little mini-tank the small pickup slurps fuel out of = the long fuel pickup, or the induction-pulsation operated diaphragm fuel pump.
More tomorrow...
Have you replaced the fuel pump gasket and diaphrgam ?