I have an old 5hp Montgomery Ward 2200 watt generator that would not run when it started getting warm. The clearance on the exhaust valve was none so when it warmed and stretched it would stay open and loose compression. I ground some metal off the tip after removing the exhaust valve and all was good again. Saved our food and normal life in Feb of 2009 when we had no power for 14 days. Ice Storm
B&S engine won’t start!
- Thread starter Kurtatron
- Start date
A retired guy around the corner from me showed me that some Briggs&Strattons have 3 holes in the jet. A starting jet, idle, and full throttle. He told me many people mis the tiny starting jet. He recommends either a fine tip needle or he uses a welder tip cleaner.
This ^^. I've been bitten by this one. Spark, compression, starting fluid and still no go.
What I do get is a literal fire outside the intake where the starting fluid has ignited on the filter housing.
^^^^Looks like the key is completely missing and the flywheel is so far out of alignment that you can't even see the shaft alignment key slot in the photo. The timing could be so far off that it's probably firing early on the intake stroke as suggested by seeing flames in the intake filter housing.
I had a lot of problems last year with my B&S not starting. Spark plug was only 1 year old Autolite and I could see it spark. After cleaning carb and still no start I put in a NGK and it started right up.
I checked the engine again. The alignment does not appear to be amiss. The coil magnets reach the coil right when the piston is near TDC.
I also boroscoped the valves. Both intake and exhaust are moving without issue.
I think the weak spark is the culprit. It’s too weak to ignite the mixture in this freezing cold temperatures.
I also boroscoped the valves. Both intake and exhaust are moving without issue.
I think the weak spark is the culprit. It’s too weak to ignite the mixture in this freezing cold temperatures.
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- Feb 6, 2025
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You're still going to need a flywheel key in there eventually.
And verify that you're getting fuel on top of the piston by removing the spark plug and shining a flashlight down in there.
And verify that you're getting fuel on top of the piston by removing the spark plug and shining a flashlight down in there.
When was the last time engine was running?
When was the last time the carb was cleaned?
Usually, a healthy spark is bluish; a weak spark is reddish. Popping out of either the exhaust or the intake would indicate that only the starting fluid is igniting and the engine is fuel-starved. Also make sure the choke is working. If you are not sure about the choke, just put your hand (wear a glove) on the intake and crank it a few times. If it tries to start then you have not working choke or clogged carb.
It seems my ignorance of carbureted engines might be a contributing reason. I thought the choke on a cold engine must be fully open to allow easier air flow. Easier airflow = easier starting.
Oops.
Choke must be closed to enrichen mixture to start a cold engine. I’ll try starting this little engine with the choke closed and see what happens.
To be honest, the choke sign is misleading. The choke arrow points to the open position. I would think the choke arrow would point to closing the choke, not the opposite.
This also makes sense because last time I ran this engine, I thought it was only running with the choke activate. To me, choke activated meant fully open butterfly valve. But my understanding was reversed. This engine ran best with the butterfly open, which is the correct position once warm.
Oops.
Choke must be closed to enrichen mixture to start a cold engine. I’ll try starting this little engine with the choke closed and see what happens.
To be honest, the choke sign is misleading. The choke arrow points to the open position. I would think the choke arrow would point to closing the choke, not the opposite.
This also makes sense because last time I ran this engine, I thought it was only running with the choke activate. To me, choke activated meant fully open butterfly valve. But my understanding was reversed. This engine ran best with the butterfly open, which is the correct position once warm.
The fact you were able to ignite the starter fluid tells me you need to adjust the valves. There are various you tube videos showing this.
That's why it's called choke because it restricts the air flow on initial start up and especially in cold weather.
Did you start the generator?
That's why cars MPG goes down in the winter because they run in choke mode longer periods of time than in the summer. Also the cold winter air contains more oxygen which the engine ECU balances with extra fuel to keep the air:fuel ratio (AFR) optimal and not lean.
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Maybe, but that would be much farther down my list as it just isn't all that common. I would definitely try a new chinese carb for between $8 and $25 long before I start inspecting keyways and other massive teardowns. These small engines almost always fail because the carb gums up from old fuel or dirty surroundings, occasionally a blocked air cleaner or, in many cases, an engine that is fine gets screwed up because an inexperienced individual starts adjusting screws on the carb or on the control cables connected to the carb. I know this, because I have destroyed a fair number of machines in my childhood or later in exactly this way. I have picked up a little along the way, and now am pretty good at getting small engines running. Good luck.
I got the engine running. It was very difficult to get started. Took several minutes of pulling. It was stumbling very low rpm until I opened the choke slightly. It ran for about 10 seconds, puffing a cloud of white smoke, then died.
I couldn’t get it to restart.
Any ideas what this could be? I don’t think it is spark related.
When it was running, rpms were good and power seemed great. I don’t think a timing issue is a problem either.
Is it a bad carb? I put on a cheapo Chinese carb, but why would it run for a few seconds then die?
I couldn’t get it to restart.
Any ideas what this could be? I don’t think it is spark related.
When it was running, rpms were good and power seemed great. I don’t think a timing issue is a problem either.
Is it a bad carb? I put on a cheapo Chinese carb, but why would it run for a few seconds then die?
Poor compression, weak spark. Out of time, carb issue. Valve leakage/adjustment.
You have eliminate each until you find the problem.
I would take off and clean the carb. Carbs have very tiny holes and they cause issues if plugged. Also the carb clean is the first thing peple do and is not hard at all if you are careful.
I usually put it apart and let it soak for a night in gasoline or or SeaFaom. Then I go through all jets and carb holes iwth carb cleaner and then I assemble it together.
The most important is to not strip any threads and bolt/jet heads. So take it easy with any screwdrivers and wrenches.
How This Story Ends.
I sold the engine to my coworker for $20.
He got it started after two pulls.
he plugged into his gas lawnmower and got it started. I literally think my only problem was I wasn’t aggressive enough with the pull. Hondas are so much easier to pull start. This Briggs needed some real muscle to get it to start. My coworker plans to use it if the engine in his log splitter goes bad.
I ended up buying a GC160 instead. For $60. It starts up nice and easy.
I knew this Briggs had everything it needed to start!
I sold the engine to my coworker for $20.
He got it started after two pulls.
he plugged into his gas lawnmower and got it started. I literally think my only problem was I wasn’t aggressive enough with the pull. Hondas are so much easier to pull start. This Briggs needed some real muscle to get it to start. My coworker plans to use it if the engine in his log splitter goes bad.I ended up buying a GC160 instead. For $60. It starts up nice and easy.
I knew this Briggs had everything it needed to start!
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