Briggs & Stratton 5kW Generator - Running Lean

All non-Cub/Cadet/IH/Farmall/Case tractor and machinery discussions.
Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.
User avatar
Urbish
5+ Years
5+ Years
Posts: 2310
Joined: Sat Sep 07, 2013 3:45 pm
Zip Code: 48158
Tractors Owned: ~
1958 International Cub LoBoy
1948 Farmall Cub
1977 International LoBoy 184
1947 Farmall H
1946 Farmall B
1953 Willys CJ3B

Cub-193 Moldboard Plow
Cub-54A Leveling and Grader Blade
Cub Loboy L-54 Leveling and Grader Blade
Unknown 5' Single Gang Disc Harrow
Circle of Safety: Y
Location: Manchester, MI

Briggs & Stratton 5kW Generator - Running Lean

Postby Urbish » Wed Apr 15, 2020 8:01 am

A friend of mine brought over her 5kW Briggs & Stratton Generator with a B&S engine on it so I could bring it back to life. This thing has me baffled. It had been left with fuel in it for years and had 1/4" of sludge built-up in the fuel bowl. I completely cleaned and rebuilt the carburetor. After reinstalling, it would run nicely but only on full choke. As you slowly move off full choke, it will start missing and shooting blue flames out the exhaust until about half choke where it completely dies. I've confirmed free flow at the gas line going into the carburetor.

I disassembled the carburetor again and double checked the main jet - all clean. The main jet is non-adjustable. After reassembling but before reinstalling, I used my air gun and blew air through the center of the bore with the butterfly held wide open (and fuel in the bowl). A nice mist of fuel/air blew out the other side. The only thing I hadn't removed was the idle mixture screw. It had a plastic limiting cap and when I pried it off the screw broke off. I extracted the portion of the screw stuck in the carburetor. I ordered a Chinese replacement carb and installed it (along with the new replacement .75" thick intake spacer that came with it) and new gaskets between all. The thing behaves exactly the same. I put the original carb back on with the idle mix screw from the Chinese one. No change. Adjustment of the idle mix screw seems to have no effect (even when fully closed) at both idle and full rpm. I sprayed carb cleaner on all areas of the intake while it was running and noticed no change. It's acting like it has a vacuum leak. The muffler appears to be flowing freely and the spark arrester screen is clean. The valves are properly adjusted.

I am at a loss. Any ideas?
Jim

Circle of Safety

User avatar
Slim140
501 Club
501 Club
Posts: 4812
Joined: Wed Nov 22, 2017 6:24 am
Zip Code: 00000
Tractors Owned: .
1970 International 140
1972 International 140
1949 John Deere A
1993 Ford 4630 W/Loader
1965 John Deere 110
1961 Cub Cadet Original
Circle of Safety: Y

Re: Briggs & Stratton 5kW Generator - Running Lean

Postby Slim140 » Wed Apr 15, 2020 8:22 am

Does it have any little freeze plug looking things on the carb where they drilled some holes and plugged them? If so take some clear finger nail polish and seal them and see if it helps.
Every home is a school, what are you teaching?

Circle of Safety

User avatar
Urbish
5+ Years
5+ Years
Posts: 2310
Joined: Sat Sep 07, 2013 3:45 pm
Zip Code: 48158
Tractors Owned: ~
1958 International Cub LoBoy
1948 Farmall Cub
1977 International LoBoy 184
1947 Farmall H
1946 Farmall B
1953 Willys CJ3B

Cub-193 Moldboard Plow
Cub-54A Leveling and Grader Blade
Cub Loboy L-54 Leveling and Grader Blade
Unknown 5' Single Gang Disc Harrow
Circle of Safety: Y
Location: Manchester, MI

Re: Briggs & Stratton 5kW Generator - Running Lean

Postby Urbish » Wed Apr 15, 2020 12:52 pm

There are bb's pressed in here and there. But I don't understand why it would exhibit the exact same symptoms even after replacing the carburetor with a new one. I sprayed down the outside of the carb as well when checking for vacuum leaks.
Jim

Circle of Safety

User avatar
Slim140
501 Club
501 Club
Posts: 4812
Joined: Wed Nov 22, 2017 6:24 am
Zip Code: 00000
Tractors Owned: .
1970 International 140
1972 International 140
1949 John Deere A
1993 Ford 4630 W/Loader
1965 John Deere 110
1961 Cub Cadet Original
Circle of Safety: Y

Re: Briggs & Stratton 5kW Generator - Running Lean

Postby Slim140 » Wed Apr 15, 2020 12:58 pm

Can you do a compression check on it? May be a sticking valve or a stuck ring if it sat that long.
Every home is a school, what are you teaching?

Circle of Safety

User avatar
Urbish
5+ Years
5+ Years
Posts: 2310
Joined: Sat Sep 07, 2013 3:45 pm
Zip Code: 48158
Tractors Owned: ~
1958 International Cub LoBoy
1948 Farmall Cub
1977 International LoBoy 184
1947 Farmall H
1946 Farmall B
1953 Willys CJ3B

Cub-193 Moldboard Plow
Cub-54A Leveling and Grader Blade
Cub Loboy L-54 Leveling and Grader Blade
Unknown 5' Single Gang Disc Harrow
Circle of Safety: Y
Location: Manchester, MI

Re: Briggs & Stratton 5kW Generator - Running Lean

Postby Urbish » Wed Apr 15, 2020 2:22 pm

Yeah, probably should have done that first. Will check. It's an OHV engine. The valve clearances were good, so guessing not a stuck valve. Doesn't seem to have excessive blowby. It doesn't smoke and there was not a mad rush of air coming out of the PCV.
Jim

Circle of Safety

User avatar
Urbish
5+ Years
5+ Years
Posts: 2310
Joined: Sat Sep 07, 2013 3:45 pm
Zip Code: 48158
Tractors Owned: ~
1958 International Cub LoBoy
1948 Farmall Cub
1977 International LoBoy 184
1947 Farmall H
1946 Farmall B
1953 Willys CJ3B

Cub-193 Moldboard Plow
Cub-54A Leveling and Grader Blade
Cub Loboy L-54 Leveling and Grader Blade
Unknown 5' Single Gang Disc Harrow
Circle of Safety: Y
Location: Manchester, MI

Re: Briggs & Stratton 5kW Generator - Running Lean

Postby Urbish » Sat Apr 18, 2020 8:27 am

Shane N. wrote:Can you do a compression check on it? May be a sticking valve or a stuck ring if it sat that long.


You nailed it. 50psi. Good enough to run on choke but not otherwise.
Jim

Circle of Safety


  • Similar Topics
    Replies
    Views
    Last post

Return to “Other Tractors and Machinery”

Who is online

Users browsing this forum: No registered users and 0 guests