My RD80763 (3300 PW) has less than an hour of runtime. Iwas using it yesterday with the 15 angle tip. After 5 minutes, the engine started shaking and blew a big puff of (oil) smoke from the muffler. I was on level ground, I had adequate water supply, I added the prescribed oil upon assembly.
In the course of the next 15 minutes, it blew smoke 2 more times. I shut it off and checked the oil...good. I started it again and ran for 5 more minutes...no problem. What happened?!
To answer the question about the customer with the oil smoke issue, the answer is that the oil is getting into the combustion chamber or muffler. Here are the possible reasons:
1. If the unit is new, it may have been stored up side down or on its side and the small amount of oil that remains in the crankcase after production will seep into the combustion chamber or the carburetor or the muffler or the breather system. If this happens the engine will smoke a little during the first tank of fuel and then run properly.
2. Another likely cause, based on the owner's description, is that there is too much oil in the crankcase. An "over fill" situation will cause the oil to either bypass by the piston and rings from the lower crankcase into the combustion chamber or bypass the breather oil control system and enter the air cleaner and carburetor. In both cases, the engine will smoke until the oil level is reduced to the correct level.
3. Sometimes the user will mistakenly use fuel mixed for their 2-cycle equipment in their 4-cycle engine. Of course, the engine will smoke profusely in that situation. The solution is to replace the mixed fuel with standard gasoline and run until the smoke clears.
4. The least likely situation is that the piston rings gaps are aligned or the rings are cracked. This is extremely rare. I have seen this twice in 20 years in this business. The engine will produce huge amount of exhaust smoke at all times that the engine is running. The solution is to replace the rings.
Based on the customers last comment: " I shut it off and checked the oil...good. I started it again and ran for 5 more minutes...no problem."
Just for fun I tried running a 50:1 mix of Stihl regular (orange bottle) 2-Cycle Engine Oil in an old Briggs & Stratton L Head (valves in block) engine. I could smell a bit more stink in the exhaust but there was no more visible smoke. Later I tried running a 32:1 mix of gasoline and #30 non detergent (the cheapo stuff) in the old B & S engine and could see some blue smoke in the exhaust, but it wasn't that heavy. With a 16:1 mix the old engine smoked heavy and the spark plug fouled quickly. I only made up small batches of the mixed fuel so I could add just gasoline and run it out.
In all of my 4 stroke cycle engines I normally run a mix of 1 Oz. Marvel Mystery Oil to 2 to 2.5 gallons of gasoline. I've found that over time this does pay off with engine life and better fuel economy. The problem is finding a good price on gallons of it. If I get it in quarts it just costs too much and thus I save no $$$ in the long run. Some time ago I stocked up on MM oil and I'm glad I did.
If someone did put the wrong fuel into the fuel tank, it would have kept on smoking until the fuel was used up, or diluted with just gasoline.
If any of you have an old junker lawnmower with a 4 stroke cycle engine, sometime put a little Diesel fuel in the tank. You want to start the engine on just gasoline, but once warmed up most will run on a 1/2 - 1/2 mix but they will smoke. You need to run the engine until you've burned up all of this fuel. Starting a cold gasoline engine on this stuff is very hard if you can do it. Starting fluid helps, but it's best to try to be careful and get things right. Do label your fuel cans well.
In the course of the next 15 minutes, it blew smoke 2 more times. I shut it off and checked the oil...good. I started it again and ran for 5 more minutes...no problem. What happened?!
To answer the question about the customer with the oil smoke issue, the answer is that the oil is getting into the combustion chamber or muffler. Here are the possible reasons:
1. If the unit is new, it may have been stored up side down or on its side and the small amount of oil that remains in the crankcase after production will seep into the combustion chamber or the carburetor or the muffler or the breather system. If this happens the engine will smoke a little during the first tank of fuel and then run properly.
2. Another likely cause, based on the owner's description, is that there is too much oil in the crankcase. An "over fill" situation will cause the oil to either bypass by the piston and rings from the lower crankcase into the combustion chamber or bypass the breather oil control system and enter the air cleaner and carburetor. In both cases, the engine will smoke until the oil level is reduced to the correct level.
3. Sometimes the user will mistakenly use fuel mixed for their 2-cycle equipment in their 4-cycle engine. Of course, the engine will smoke profusely in that situation. The solution is to replace the mixed fuel with standard gasoline and run until the smoke clears.
4. The least likely situation is that the piston rings gaps are aligned or the rings are cracked. This is extremely rare. I have seen this twice in 20 years in this business. The engine will produce huge amount of exhaust smoke at all times that the engine is running. The solution is to replace the rings.
Based on the customers last comment: " I shut it off and checked the oil...good. I started it again and ran for 5 more minutes...no problem."
Just for fun I tried running a 50:1 mix of Stihl regular (orange bottle) 2-Cycle Engine Oil in an old Briggs & Stratton L Head (valves in block) engine. I could smell a bit more stink in the exhaust but there was no more visible smoke. Later I tried running a 32:1 mix of gasoline and #30 non detergent (the cheapo stuff) in the old B & S engine and could see some blue smoke in the exhaust, but it wasn't that heavy. With a 16:1 mix the old engine smoked heavy and the spark plug fouled quickly. I only made up small batches of the mixed fuel so I could add just gasoline and run it out.
In all of my 4 stroke cycle engines I normally run a mix of 1 Oz. Marvel Mystery Oil to 2 to 2.5 gallons of gasoline. I've found that over time this does pay off with engine life and better fuel economy. The problem is finding a good price on gallons of it. If I get it in quarts it just costs too much and thus I save no $$$ in the long run. Some time ago I stocked up on MM oil and I'm glad I did.
If someone did put the wrong fuel into the fuel tank, it would have kept on smoking until the fuel was used up, or diluted with just gasoline.
If any of you have an old junker lawnmower with a 4 stroke cycle engine, sometime put a little Diesel fuel in the tank. You want to start the engine on just gasoline, but once warmed up most will run on a 1/2 - 1/2 mix but they will smoke. You need to run the engine until you've burned up all of this fuel. Starting a cold gasoline engine on this stuff is very hard if you can do it. Starting fluid helps, but it's best to try to be careful and get things right. Do label your fuel cans well.
Comments
Post a Comment