LawnMower Plug Fouling

[Stratosfied]

I have a Cub Cadet 21" Pushmower Self Propelled with a 6.75 Briggs & Straton Industrial Engine. The thing puffs a bit of black smoke when I crank it but otherwise doesnot smoke nor seem to use oil. The plug fouls about every 2nd time I cut the grass. It takes me 45 mins to do the front and sides and about 45 mins to do the back. I pull the plug and clean it up and it goes on again. The plug has black soot on it and it is not hard to get going again but really beginning to be a pita. Any suggestions, The mower cranks and runs fine otherwise. This occurs with the new plug also.

 

[Bob_VT]

Re: LawnMower Plug Fouling

Your probably running a plug that is "cold" and the plug is not hot enough. Bring the plug to a parts store and ask for the next heat range. Be sure the plug is the same length in the threads.<br /><br />Bob

 

[jlshields]

Re: LawnMower Plug Fouling

Very dirty air cleaner will cause the engine to run rich and foul the plug.

 

[Stratosfied]

Re: LawnMower Plug Fouling

I have been on the web and phone with Briggs & Stratton this am. They cannot find the model in their computers, nor could I on the web. I am thinking along with jl, that the air filter may be the culprit. It has a foam liner over an oval pleated filter. Should you still oil the foam part of the filter? Thanks for the help and any more, I will work on it some more and post throughout the day.

 

[mattttt25]

Re: LawnMower Plug Fouling

double check your mix before anything else. even the best of us screw up the ratio from time to time. i'd start with a fresh batch of gas and mix to proper ratio. run a tank or two with clean plugs and see what happens.

 

[Stratosfied]

Re: LawnMower Plug Fouling

Thanks, this is a straight gas mower.

 

[dolluper]

Re: LawnMower Plug Fouling

Black plug suggests your running rich,mixture rich[carb setting] or choke staying closed[not open] or as stated above clogged up air filter

 

[ED21]

Re: LawnMower Plug Fouling

Make sure the choke isn't sticking partially closed or is loose & closing on its own.

 

[DJ]

Re: LawnMower Plug Fouling

Very dirty air cleaner will cause the engine to run rich and foul the plug.

Ditto.

 

[mattttt25]

Re: LawnMower Plug Fouling

woops. sorry.

 

[LubeDude]

Re: LawnMower Plug Fouling

Originally posted by Stratosfied:<br /> Should you still oil the foam part of the filter?

I think that the foam is just a pre filter and should "NOT" be oiled unless it says so in the manual. Even then, there is a very normal tendency to overoil them. They should be lightly oiled and rung and blotted out befor using. This will cause the problems you are expirencing. If you had too much oil, you could have contaminated the paper filter also. If the paper filter has oil on it, it is ruined.

 

[JRJ]

Re: LawnMower Plug Fouling

Try a new filter and plug. I've never had this kind of problem running B&S in different applications for 47 years. My latest is on a Sears mower without a choke or throttle. Full speed after you pump a little bulb. How can that be good?

 

[Bart Sr.]

Re: LawnMower Plug Fouling

I bought a used Murray a few years ago and the plug was fouling terribly.So I took it to the dealer I purchased it from(about 200 yards up the street)and they pulled the head and found that the head gasket was blown allowing oil into the cylinder.That was two years ago and haven't a lick of trouble since.The mower has a 14.5 horse Briggs.

 

[Stratosfied]

Re: LawnMower Plug Fouling

I bought a new filter and lightly oiled the foam pre filter per the instructions. While I was doing all this, I drained the oil and while putting the thing back together, I put the "engagement" assembly which engages the drive, in incorrectly. So... off I go to the dealership 25 miles away to get a new collar that fits on the shaft which holds the blade. This collar is made of cast iron and is there to help keep from spinning the crankshaft key. While there got a new blade as well. Got home and put it all together and busted the new collar, (this is when I saw that I had the assembly wrong). Got frustrated and went and had a brew. Will go get another collar and a plug this am.

 

[Stratosfied]

Re: LawnMower Plug Fouling

ShaaZamm!!! She is out there purring like a kitten right now!! Thanks to all my iboats friends for their help and suggestions!