Faulty Diaphram?? Mower Engine quits quickly

Reply

  #1  
Old 04-09-07, 04:26 PM
ofairlane's Avatar
New Member
Thread Starter
Join Date: Nov 2006
Location: Thomaston, CT
Posts: 63
Faulty Diaphram?? Mower Engine quits quickly

Hey all, Happy Easter is behind us an lawn mowing ahead of us. I picked up a Toro walk mower with a B&S 6 HP motor. The darn thing won't start unless I pour a bit of gas into the carb. It will only run on that gas though, once that gas is gone, nada.
So, obviously there is spark, there is gas in the tank, line and in the bowl, the float and needle valve work fine and still no start.
I am guessing it's that darn diaphram that works off the valves. I think it causes suction to pull the fuel into the carb, but I am not sure. I can get a Ford 289 running great, but I am not so good with the little ones.
Let me know if you have crossed this bridge before and if I am understanding the carburation theory correctly on these motors.

Thanks again.
DanO
 
Sponsored Links
  #2  
Old 04-09-07, 04:49 PM
puey61's Avatar
Member
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
Being a 6-horse this engine should not be a diaphragm type carburetor, rather is shoud be a bowl type as, I believe, you noted. What draws fuel into the combustion chamber is piston movement timed right with intake valve opening. I'd say you have a carburetor that is varnished up and in need of a soaking and reconditioning with the proper Briggs rebuild kit. If you post back with engine ID numbers I'll provide you with the part number(s) you will likely need.
 
  #3  
Old 04-10-07, 03:30 AM
ofairlane's Avatar
New Member
Thread Starter
Join Date: Nov 2006
Location: Thomaston, CT
Posts: 63
puey, you sound like you know what you are talking about. The ID numbers I took off the flywhhel cover are as follows. Model 12H807-1760-EI and the code# is 980022056.
I was thinking a diaphragm because I thought that was what the part was called. The carb is a bowl type, with no adjusting screws, no idle speed screw, no mixture screw, etc. There is an airline from the air filter to a diaphragm part at the valves, I thought that is what drew the fuel into the carb, it is a bowltype, I believe gravity filled carb. I did clean it out with new gas, blew low pressure air into all small openings and it seems clean, but easily gummed up is still a real possibility.
Thanks
 
  #4  
Old 04-10-07, 04:55 AM
puey61's Avatar
Member
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
The "airline" you refer to is the crankcase breather tube. This carburetor is a non-adjustable type but I've assumed it is one of three possibilities based on the fact that it is a Toro unit (primer, choke or auto-choke style) with primer being my assumption. With such the carburetor rebuild kit is Briggs part number 498260 and the main jet/bowl nut is part number 494870. If you have anything other than a primer style AND if you are at elevations above 1500 feet above sea level, post back with this information otherwise proceed as normal. I suggest soaking in a quality bath type cleaner (I like Napa #6402) for 15-30 minutes, depending on the amount of varnish build-up. The rebuild kit may have parts not required, particularly the idle circuit metering screw, so just disregard those unneeded.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes