Briggs and Stratton fuel issue (2022)

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mjed0

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Discussion Starter·#1·Feb 10, 2016

I have a briggs and stratton 450 series 148cc lawnmower. 2 1/2 years old. I cut the lawn last in November and now it won't start after the 3ish month break. I sprayed starting fluid in the cylinder and it ran for the typical 1-2 seconds you expect, tried spraying straight in the carb next with same 1-2 second running result. I then poured a tad of gas in the carb, again ran for 1-2 seconds and dies. The gas I poured in the carb is the same source as the gas I filled the tank with, although the gas in the tank has been in there since November.

Is 3 months enough for the gas to go bad in the mower tank? Or could I be looking at another reason why the fuel may not making it from the tank and through the carb to keep it running? Also, I primed the bulb repetedly to no avail.

Also worth noting, when trying to run it today I started it for that 1-2 seconds about 8 times. After that I noticed black oily liquid dripping out the muffler, could that be excess from floooding the carb a few times with the gas?

Any suggestions appreciated.

AVB

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#2·Feb 10, 2016

Could be but I would check the oil level now. It sounds like the float needle valve is struck from gumming fuel residue. If the needle frees it could stick open causing the engine to flood the crankcase with fuel diluting the oil and then oil could run out the muffler.

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(Video) Briggs and Stratton Fuel Pump Replacement - $6 QUICK FIX!!!

Discussion Starter·#3·Feb 11, 2016

Thanks for the reply, yes I'll definately check the oil just in case. But I was putting quite a bit of gas down the carb, so won't be surprised if it's that. As for the starting, I'm wondering if it's rubber O rings or something. I've read about those online but not sure it that applies to the 450 series engine, also could rubber rings already go bad on a 2 1/2 year old engine?

AVB

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#4·Feb 11, 2016

I don't know the fuel in England but with today's fuels here in the US anything is possible. I have carburetor completely gummed up in a few months of none use. I have seen rubber components to swell, harden and a few to turn to mush because of fuel and it additives.

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#5·Feb 11, 2016

(Video) Lawn mower fuel pump check

Three months (ish!) is plenty of time for the fuel to go "stale" and gum up the carb. Your oily residue from the muffler is just the excess fuell washing out the carbon etc. While doing that it will also be washing the lubrication off the cylinder bore!
Its a valid point that has been made re contamination of sump oil so the sooner the carb is sorted the better.
You may be able to clean the carb with a proprietary aerosol of carb cleaner but if that doesn't work it will be a trip to someone with an ultrasonic cleaner.
Just may be worth pricing a new carb - note the model, type, and code numbers and letters stamped into the engine cowling and key them into an on line parts list .

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Discussion Starter·#6·Feb 12, 2016

Thanks for the suggestions. I'm going to get a can of carb cleaner today and hopefully that sorts things. Next step if that doesn't work is taking a look at any rubber components and see what they look like. Thanks again.

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Discussion Starter·#7 ·Feb 24, 2016(Edited)

Re: Briggs and Stratton fuel issue 450 series

Just to update, I have now replaced the fuel, cleaned the carburetor with carb cleaner, cleaned filter on the pickup tube, put a new carb gasket and diaphragm in, cleaned off the air filter (though it was fairly clean still), checked and changed the oil (wasn't contaminated), cleaned up the spark plug and cleaned out the gas tank. It's all back together and I'm very satisfied with how it all went back together and how clean it all is, yet the exact same symptoms persist. I can still get it to run for a second or two with a shot of starting fluid or gas but won't run on it's own accord. I experimented by starting it by pouring a bit of gas in the carb, once it started I quickly continued trickling gas into the carb and ran it that way for about 30-40 seconds until I stopped pouring, then the engine died immediately. For some reason it won't pick up fuel from the tank below and keep running.

Rather frustrating, any other suggestions appreciated.

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(Video) Fix 90% of Briggs lawn mower not starting problems. Easy repair.

wristpin

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#8·Feb 24, 2016

Somewhere in your carb there is still some gum or worse, some corrosion caused by water absorbed by the ethanol in the fuel - ethanol being hygroscopic. You can try another thorough clean with carb cleaner but an ultra-sonic clean stands the best chance of success. Failing that, it's new carb time.

AVB

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#9·Feb 25, 2016

I look-up these engines by the model numbers and not the series. but after re-reading the posts I think you got a Pulsa-Prime carburetor. So this your carburetor?

Briggs and Stratton fuel issue (4)

I don't see this too often but if it won't prime the primer check valve may be stuck open. This is behind the primer bulb. It consists of rubber seat and a spring loaded steel ball. I have these steel ball rusted and sticking open and carburetor can not prime.

Here is some instructions of repairing these.
Disassembly, Cleaning and Repair of Briggs and Stratton Tank-mounted Pulsa-Prime Carburetor

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(Video) Small Engine Repair: Checking a Vacuum Fuel Pump / Fuel System on a Kohler V-Twin Engine

Discussion Starter·#10·Feb 26, 2016

AVB, thanks so much for your detailed response, but at last the problem is sorted. While I changed the fuel early on in this problem, it was from the same jerrycan. I only filled the jerrycan last November and it's been stored in the shed with mild weather for that almost 3 months, yet it appears the fuel went bad. I have seen gas last well over a year in a jerrycan so this really surprised me. I can understand it going bad within the tank, lines and carb of a mower, and even then 3 months seems quick, but I'd never guess a jerrycan full would go bad in such a short time.

Anyway, long story short...new gas and it's starting and running great. I think all the cleaning and servicing hasn't hurt matters anyway, it's like new now!

Thanks again for everyone who offered advice, much appreciated. :thumb:

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#11·Feb 26, 2016

Don't feel bad at least you found it before ordering any major parts. Once I purchased 5 gallons of fuel while I was tilling my garden. The tiller ran out so I refilled the tank. I didn't even get 10 feet before the engine shut down and a Troy-Bilt Horse is not that easy to get out tilled ground. Pulled the carburetor's fuel bowl and it was full of water then drain the fuel tank again nearly full of water. I then poured the fuel that I just purchased into a clear container. It turned out I had got over two quarts of water in the fuel I just purchased. On that Jerry can make sure it air tight seal as if your fuel contains Ethanol it will attract moisture from the air easily.

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Discussion Starter·#12·Feb 27, 2016

Thanks again AVB, now I don't feel so bad, I expect getting that tiller out of the ground was a workout! As for the jerrycan, I got a new one for the new fuel and the only parts I bought was the gasket/diaphragm for the carb, so all should be good now. :grin:

(Video) Cheap fuel pumps are junk!!??

FAQs

Why is my Briggs and Stratton not getting fuel? ›

Loose, Dirty or Disconnected Spark Plug in Your Lawn Mower: Check it out, clean off debris, re-connect and tighten. Dirty Air Filter: Clean or replace. Fuel Not Reaching the Engine: Tap the side of the carburetor to help the flow of gas. If this doesn't work, you might need a new fuel filter.

Why is my lawnmower not getting fuel? ›

If you still don't get any gas, the fuel line is kinked or plugged. And check inside the tank for any debris that might clog the outlet. If you're getting gas to the lawn mower carburetor, check to see if there's any fuel in the bowl. Clamp off the fuel line with a C-clamp.

Why is my lawn mower not getting gas to the carburetor? ›

A lawn mower carburetor will not get fuel when old gas corrodes fuel components and leaves gummy deposits restricting the fuel system. A plugged fuel filter; clogged or kinked fuel lines; a faulty fuel pump; stuck carburetor float and float needle; or bad gas cap can result in a lawn mower carburetor not getting fuel.

How do you test a Briggs fuel pump? ›

HOW TO TEST a Riding Lawnmower FUEL PUMP. The EASY WAY!

Why is my carburetor not sucking fuel? ›

float may be stuck in the closed position or if carburetor equipped with a electric shut off/solenoid it could be faulty/stuck/bad connection. Now if you are getting fuel to carb. and the bowl is filling, either the jets are clogged or you have not adjusted the screws out to the proper settings to allow fuel to flow.

Why is there no fuel getting to my spark plug? ›

Common causes include a dirty air filter, spark plug, and carburetor. To fix these issues, replace the fuel filter, clean the carburetor and spark plug, and replace the fuel if it is old as illustrated below.

Why is my lawn mower turning over but not starting? ›

Q. Why is my lawn mower turning over but not starting? The most likely reason is bad gas. Gas that sits for many months during the off-season will eventually break down, gumming up the fuel line and carburetor in the engine and preventing it from starting.

How do I know if my lawn mower fuel filter is clogged? ›

  1. Poor Engine Performance. Under heavy loads, a clogged fuel filter may cause the engine to randomly hesitate, surge or sputter. ...
  2. Hard Starting. Unless totally blocked, rarely will a bad fuel filter keep your engine from starting. ...
  3. Stalling. ...
  4. Random Misfire or Rough Idle. ...
  5. Fuel System Part Failures.
Jul 28, 2020

Why is my lawn mower starving for fuel? ›

Clogged Filter

Some push mowers have an inline filter between the gas tank and the carburetor. If yours does, it could be clogged with any dirt that had settled in the gas tank. These filters are typically spliced into the gas line and held in place with small clamps.

How do you unclog a carburetor? ›

How To Clean Clogged Carburetor Jets - YouTube

How does a Briggs and Stratton vacuum fuel pump work? ›

Briggs & Stratton fuel pumps have either a plastic or a metal body and develop pressure using the vacuum in the crankcase, which is created by the motion of the piston. A fitting on the crankcase cover or the dipstick tube draws the pressure to pump fuel.

How do you manually prime a carburetor? ›

Simply cranking the car for 10 - 15 seconds should prime the carb.
  1. Crank the car for about 15 seconds.
  2. Stop for about 15 seconds.
  3. Pump the accelerator petal twice.
  4. Crank the car again, if it doesn't start immediately keep cranking the car for a maximum of 15 seconds.
Jan 25, 2013

How do I know if my lawn mower fuel pump is bad? ›

Is My Fuel Pump Going Bad? Here Are 8 Signs It Is!
  1. Fuel Tank Noise. A damaged fuel pump might make a loud, whining sound that you'll hear from your gas tank. ...
  2. Difficult Starts. ...
  3. Sputtering Engine. ...
  4. The Actual Stall. ...
  5. Power Loss. ...
  6. Surging Power. ...
  7. Lower Fuel Efficiency. ...
  8. Dead Engine.
Jul 1, 2020

How do you test a fuel pump on a small engine? ›

Checking a Vacuum Fuel Pump / Fuel System on a Kohler V-Twin Engine

How do you fix a vacuum on a fuel pump? ›

Briggs & Stratton Fuel Pump Vacuum Tube Repair on Lawn Tractor

How does gas get in oil in a Briggs & Stratton engine? ›

What causes fuel to leak into my engine oil? The fuel shut-off valve isn't closed properly. Fuel float in the carburetor being stuck in the open position due to gumming (caused by stale fuel) or debris.

Why is my lawn mower turning over but not starting? ›

Q. Why is my lawn mower turning over but not starting? The most likely reason is bad gas. Gas that sits for many months during the off-season will eventually break down, gumming up the fuel line and carburetor in the engine and preventing it from starting.

Why does my small engine only start with starter fluid? ›

Why Does My Mower Start With Starter Fluid Then Die? (The Short Answer) The main reasons for why your lawn mower starts with starter fluid then dies are: issues with the carburetor, a clogged air filter, bad or old gas, spark plugs that aren't firing correctly, and an improper oil level.

How does Briggs and Stratton fuel pump work? ›

Briggs & Stratton fuel pumps have either a plastic or a metal body and develop pressure using the vacuum in the crankcase, which is created by the motion of the piston. A fitting on the crankcase cover or the dipstick tube draws the pressure to pump fuel.

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