My Lawnmower Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
I have a Briggs carb # 692814 on a model 461777 0137E1 code 9802035A ( opposed twin 2 20.5 hp engine engine) that runs rich at idle. I have rebuilt the carb ( ultrasonic cleaner ) and used a new kit and the included with the kit jets. It improved the idle somewhat but not 100% as it is still slightly rich at idle. Is there a way to add a mixture idle adjuster to this carb?? Or am I overlooking something. This is the first fixed mixture carb I have run across that is rich rather than lean. The carb does not appear to be flooding over and runs well at all speeds except for a slightly fat idle that is driving me up the wall. No gas in the oil --air filter clean--same problem with air filter off the engine. Thanks in advance for any help or thoughts on this. Rick
 

·
Premium Member
Joined
·
5,898 Posts
Just a wild thought, were they the right jets? (High altitude/low altitude) Maybe someone has encountered this and will chime in.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #4 ·
I'll check to make sure the jets are the correct size for my altitude. I suspect they are as the mower was not from a high altitude area and the jets were the same size in the new kit. The new kit # is 693503 for oe and 22-10938 for after market which is the one I used. But then you just never know what the p o had done with his equipment . Thanks for the quick reply's. Rick
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #5 ·
Wait---The coffee just kicked in and jump started my morning brain with this thought. If the jets I have are for high altitude wouldn't they be smaller to lean out the mixture due to less oxygen at the higher altitudes ???
 

·
Registered
Joined
·
507 Posts
Yes they should be. I don't think the new jets is your issue. Thinking out loud here, there could be some dirt in the seat not causing the needle to set fully. If I'm right, it wouldn't flood when not running because this engine has a fuel pump. Once its running, fuel could be pushed in through a tiny gap in the needle/seat and that could be your issue at idle as it would use more fuel revved up. Just a theory.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #7 ·
Vortec7622 Your theory is based on sound thinking but when the engine is running there will always be a small amount of fuel going thru the needle and seat but a slight imperfection in the needle or seat could cause a rich running condition but usually causes flooding. I did look at the needle and it appears to be able to seal correctly. I now have a used replacement carb that I will go thru and install to see how it works and if it cures the problem fine but if not then I plan to drill and tap the sealed idle circuit and install a mixture screw assembly. I have a good stash of carb parts from years of rebuilding automotive carbs but not small engine carbs. Your 15 year old brain seems to work in a way that will lead to a great mechanical ability. It will be awhile before this gets done as the boating season in now in full swing. Keep thinking out loud Rick
 
1 - 7 of 7 Posts
Top