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Smoking engines update


Brent_Baumer

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Well, if you recall the 16 horse briggs passed the manometer test for the breather check, and smoking was reduced by rebuilding the carb and leaning out the mixture and changing the oil to fresh straight 30W. The thing still smokes but now definitely oil. Oil is blue and much lighter than before. Next step was to borrow this Kohler leakdown tester from a friend:

After finding TDC and going a little past and testing the seal with lung power, I hooked up the air and it failed miserably. Smoke in this case is definitely caused by blow-by. Put the same tester on the smoking kohler and it tested out in the "low" leakage range, but pretty close to the yellow moderate area. Judging by how black and fouled the plug is in the kohler, I think too rich may be the problem there. Now what to do for the briggs. Contemplating trying this stuff just for grins but don't want to blow up the motor before I rebuild it:

Brent
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There is no miracle cure for worn parts, although Rislone makes some fine products I would guess you will find a worn cylinder or rings, not rings stuck with carbon which this stuff helps free up. Just my 2 cents though!
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Brent Just for the heck of it put some ATF in the cylinder and let it set for a day or two. Then drain off about ½ qt. of oil from the crank case and add ½ qt. of ATF to the crank case and let it run a couple of hours. If you have sticking oil rings this will clear it up. if it doesn't then it is time for a ring job.
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Marvel Mystery Oil will work as well. I use it every time I crank up an engine that has been sitting a long time, its good for upper cylinder lubrication, but it will smoke like a freight train until it burns out. I also put it in smoking engines on push mowers, it reduces the smoking, but will not compensate for old, worn components. If you have anything with stuck rings, put some Marvel in it and let it sit for 3 days. It should release them and be able to run again.
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Brent some of the blowby and compression loss could be valves not rings. Have you pulled the head are the valves burned? seats could be bad? I believe the old car trick was to do a wet cpmpression to isolate valve leakage.
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