Semi-seized BR420

40fnniners

Forum Newbie
Joined
Mar 22, 2017
Threads
1
Messages
2
I picked up a used BR420 from Craigslist for cheap. Guy said he put it in the garage running, and came back to it the next season and couldn't get it to crank. Said he was mechanically challenged, so put it up for sale. I brought it home and ended up getting some life out of it by making sure the spark plug was connected. It purred quietly for 15-20 seconds and went back down. I got excited and kept at it, getting a little more out of it, but all of a sudden seized it up.

Watching Youtube, I drained the fuel, removed the spark plug, poured in a little bit of 50:1, and refueled. One guy waited 24hours, but another kid went straight at it. Impatiently, I went straight for it, and it's still catching.

The weird thing is, once the spark plug is removed, it un-seizes completely. I am going to quit messing with it for now and let you guys give it some thought. I've got a guy a half-hour away that can probably tackle it for pretty cheap, but hoping it's something quick I can fix on my own.

Let me know.
 

reynoldston

Lawn Pro
Joined
May 23, 2011
Threads
92
Messages
5,705
I picked up a used BR420 from Craigslist for cheap. Guy said he put it in the garage running, and came back to it the next season and couldn't get it to crank. Said he was mechanically challenged, so put it up for sale. .

Just maybe Guy left out part of the story. Like running it out of oil or the number of seasons it sat?
 

40fnniners

Forum Newbie
Joined
Mar 22, 2017
Threads
1
Messages
2
Just maybe Guy left out part of the story. Like running it out of oil or the number of seasons it sat?

Maybe, but I am thrown off on how it was not seized when I first started messing with it. It pulled like a dream at first, and still does when the plug is removed. Wondering if the spark plug got snagged somehow and is protruding too far out now, causing things to bind up.
 

reynoldston

Lawn Pro
Joined
May 23, 2011
Threads
92
Messages
5,705
I had to look to see what a BR 420 was. I see its a blower so its 2 cycle engine. Maybe it has a large carbon build up in the combustion chamber. Dose the plug look like its hitting the piston?
 

nhyrum

Member
Joined
May 29, 2017
Threads
1
Messages
26
If it "unsiezes" with the plug removed you're likely feeling the compression. It is a rather large engine at 56cc.

Have you pulled the carb if and taken it apart to make sure it's not filled with varnish?

Also, take out the spark arrestor, or at least take it out and heat it with a propane torch for a good long while then take a brush to it.
 
Top