Briggs and Stratton 300E surging bad

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banjomaniac

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I bought this Murray mower for a friend who is kind of down on their luck thinking I could put a blade on it and have them a good mower but it's surging really bad. I can watch the governor moving back and forth so I pulled the carburetor apart 3 times cleaning it very well I did not use carb cleaner because it's plastic but I pulled the plastic jet tube out everything looks really good in this carburetor. Put it back together and its still surging. I can hold the governor arm slightly in and it runs nice and smooth spring looks good on the governor but I was wondering if I just put a heavier spring on if it would hurt anything? Now this mower doesn't have a blade on it right now I also wondered if just not having the blade can cause this to run this way?

Banjomaniac
 
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shiftsuper175607

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banjomaniac said:
I bought this Murray mower for a friend who is kind of down on their luck thinking I could put a blade on it and have them a good mower but it's surging really bad. I can watch the governor moving back and forth so I pulled the carburetor apart 3 times cleaning it very well I did not use carb cleaner because it's plastic but I pulled the plastic jet tube out everything looks really good in this carburetor. Put it back together and its still surging. I can hold the governor arm slightly in and it runs nice and smooth spring looks good on the governor but I was wondering if I just put a heavier spring on if it would hurt anything? Now this mower doesn't have a blade on it right now I also wondered if just not having the blade can cause this to run this way?

Banjomaniac
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Look below at Similar Threads for a reply on the same problem of same engine.
 
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banjomaniac

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I've had it apart 4 times, followed the video and even popped out that tiny steel ball, this carb is clean ask new. I ran the wire through all the Jets and even used a magnifying glass to look, it is clean. It looked good the first time I took it apart. The gasket looks good, o ring is there. I watched several videos on cleaning this carb but still surges. Only thing I can figure is it has a vacuum leak or down inside carb base where you can't see or get to has a blockage but I really doubt it. I give up.
 
Boudreaux In Eunice La.

Boudreaux In Eunice La.

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Ok the next thing would be to give the governor spring a good look over........ They break very easily..... I keep 4 or 5 in stock all the time.....

The spring will be on the under side... Not on the top side like older style engines.... If the spring is broke it will surge....

OR the guy you got it it from disconnected the governor arm from the engine...... Or it could be a fuel line gone bad on the inside of it.....

Fuel lines go bad all the time, and there is no way of checking them by blowing thru them.......
 
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bertsmobile1

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There is a short manifold that the carb mounts on to.
It is held on by the bracket the card sits in and seals via an O ring.
So take it off and check the O ring for damage.\People who are not familar with these carbs regularly loosen off these screws but fail to tighten them or allow debris to fall under the O ring when removing or replacing the carb.
It is part 122 ( O ring + manifold ) in this diagram https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/briggs-stratton/020000-09z999-series/08p500-to-08p599/08p502-0003-h1/carburetor
Also check the o ring between the carb & the manifold part 617 for nicks that can be leaking air.

Two side to surging
not enough fuel
too much air.
So air entering after the right amout of fuel has been added will also cause surging.
The O rings are cheap so I like to replace them regardless a belts & braces fix.
 
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banjomaniac

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I had the carb Bowl off this last time I went ahead and connect to the fuel line and manually work the float gas runs out at a pretty good rate so I don't think there's a problem with the fuel line also the O-ring and plastic keeper are there I made sure to snap them back in the carburetor and the gasket on the underside of the carburetor where it meets the intake looks good I'm at a loss to governor spring is in good condition I actually tried shortening it a hair to see if it would help the arm is connected only thing I can think is down in the bottom of the carburetor when you slide the plastic tube down in there that has the Jets that bottom part of the carburetor may have something in it but I sure can't see it I shined a flashlight use the magnifying glass.
 
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Boit4852

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From the original post, you state that you are running the engine without blades. Blades add inertia to the engine which smooths out the engine mostly at low RPM. Install blades and see if that corrects your issue.It's not surprising that without blades installed that you would experience engine surging issues.
 
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banjomaniac

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Put a new blade on and it runs perfect, it didnt have a blade when I bought it and I was going to give it to a friend in need so I didn't want to buy a blade if it didn't run right I should have known better which is why I asked in my first post if that might cause this problem now everybody knows if it's set up to run with a blade it might run bad without one. Thanks for all the help.

ROW FASTER, I HEAR BANJOS!
Banjpmaniac



Boit4852 said:
From the original post, you state that you are running the engine without blades. Blades add inertia to the engine which smooths out the engine mostly at low RPM. Install blades and see if that corrects your issue.It's not surprising that without blades installed that you would experience engine surging issues.
Click to expand...
 
Boudreaux In Eunice La.

Boudreaux In Eunice La.

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I thought I said in my first post too put a blade on it...... I guess my edit didn't go thru.......

Glad you got it going,,,,,, Now remember that newer style engine has small jets and does NOT like ethonal gas at all....

Plus Tard Mon Ami ~!~!
 
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