Engine carbon cleaning

[agford4x4]

I have a 12hp B&S engine that runs really well. I bought it used, and when i pulled the plug, there is caked on carbon, it hasnt been changed since new in 1992. Anyway, i put a new plug in and pulled it after a few hours of use and noiticed a film of oil on it, why i don't know. The engine was owned by a guy i know who is particular about maintenance. I also have another B&S engine that is essentially brand new and it has the same thing so i dont think its a problem. At any rate, there IS caked on carbon on the valves and on the cylinder that i can see through the spark plug hole. Do you recomend pulling the head and scrubbing that off? I don't think its something that is going to be removed otherwise. I have pulled hte head on other engines to do this so its not a big deal.

 

[thatguy]

I understand that 'seafoam' does miracles on some items like this.. BUT like all things some say it doesnt work at all and others swear by it..

good luck

Brian

 

[Bird]

I had a boat motor recently that wouldn't idle and used Mercury Power Tune, by following the instructions on the can and that very promptly fixed the problem. I wonder whether it wouldn't work on Briggs & Stratton engines, too. I'm sure you can buy it at most any boat dealer that sells Mercury motors.

 

[art]

Years ago while working in a car dealership one of the shops lead mechanics told me that to make it easy for clean-up while rebuilding to get the engine warmed up and to hold it up about half throttle or at least enough for it not to stall and to take a spray bottle of water and spray it in the carb, I think it works great! Every engine I rebuild that I know needs it and not looking for an individual flaw it will take the carbon off and leave the parts nice and steam cleaner clean!

 

[coobie]

Seafoam or BG-44K products.Both are good products.coobie

 

[Shimon]

I've had good success with Seafoam. I keep a couple of bottles around.

 

[Molerj]

I would pull the head, take a wire wheel on a drill or 4 1/2" angle grinder & clean it off. Leave piston at end of travel, then back off a little to get the ridge that will be on the end of the cylinder. Should replace the head gasket & torque the bolts in the proper tightening sequence.

 

[caddelma]

I have had luck using Seafoam and/or Deep Creep (aeresol version) in both outboards and mowers (2 and 4 stroke).

 

[agford4x4]

I pulled the head. Seafoam does work pretty good. I used a can on this engine. However, it will NOT get 20+ years of carbon off the piston. I cleaned it with a wire brush, now i just have to put the head and gasket back on. I dont have a torque wrench or manual for it. Ive never needed one for small engines. I always torque everything between 'not tight enough' and 'too tight'.

I asked because i wasnt sure if it was necessary. Then last night, i decided to take the hood off, and then take the spark plug out to look.....then i took a cover off....then i figured what the ****, ill pull a bolt and see if its easy to take out....before i knew it, i had the head off and was committed.

Works for me.

 

[BrianW]

Years ago while working in a car dealership one of the shops lead mechanics told me that to make it easy for clean-up while rebuilding to get the engine warmed up and to hold it up about half throttle or at least enough for it not to stall and to take a spray bottle of water and spray it in the carb, I think it works great! Every engine I rebuild that I know needs it and not looking for an individual flaw it will take the carbon off and leave the parts nice and steam cleaner clean!

Back in the 70's when I was working as a mechanic there were a lot of problems with cars carboning up and fouling plugs. We used to use the water trick to fix them. Kind of like steam cleaning the interior of the engine.

 

[xmitterengineer]

Back in the 70's when I was working as a mechanic there were a lot of problems with cars carboning up and fouling plugs. We used to use the water trick to fix them. Kind of like steam cleaning the interior of the engine.

FWIW.... Back in the early 80's I did the water decarb trick to my 350 Chevy.

That night the crank broke in the throw between the rear main journal and the #7 and 8 rod journal!!!

Coincidence?

I will probably never know.

Maybe I hydro-locked it by being over enthusiastic with the water application?
Of course that would have been my fault as it could have been done correctly with good results.

Needless to say I have not used this technique since.

Rickey

 

[RalphVa]

My father was a mechanic. I've seen him pouring (gentle stream) water into the carburetor intakes of cars to decarburize them.

In these days of unleaded fuel, I doubt this is needed.

It if ain't broke, don't fix it. In my younger days, I'd often do preventative maintenance by removing heads and what not. There are too many other things to have more fun with now. I don't fix them until they squeal or break.

Ralph

 

[Ifixcars]

I agree with Ralph. If it's getting the job done without complaints, leave it alone. Carbon is fairly common on older small engines. I don't peek into my small engines to find more work to do. However, on the subject of carbon cleaning, GM top eng cleaner works well. On cars, I feed some into a warm idling engine either thru the carb or a manifold vac source until the motor runs very rough or stalls. This coats the valves with the cleaner. Then I pull the plugs, and drizzle some onto the pistons. Let it sit till the engine cools. Cover the plug holes with a rag, and spin the engine over, expelling a nasty blast of top engine cleaner and carbon. Re install the plug and fire up. Away you go in a cloud of smoke, decarboned for the time being. Has never failed, at least to amuse me when I road test afterwards and blow out all the carbon and cleaner.

 

[BrianW]

FWIW.... Back in the early 80's I did the water decarb trick to my 350 Chevy.

That night the crank broke in the throw between the rear main journal and the #7 and 8 rod journal!!!

Coincidence?

I will probably never know.

Maybe I hydro-locked it by being over enthusiastic with the water application?
Of course that would have been my fault as it could have been done correctly with good results.

Needless to say I have not used this technique since.

Rickey

Using a mist bottle will help eliminate that possibility, but pouring it in will definitely hydro lock the engine!