Briggs Intek 825 burning oil?

[lambostefan]

Hi guys,

i got a used small lawn mower last year. Since the previous owner had already tried to repair the mower, everything was no longer in its original condition. Engine model is Briggs Intek 825 (Engine No 122607-0210-E1) OHV.

Since it wouldn't start, I carried out the following repairs:

- new ignition coil because the old one was rusted
- Replaced crankcase breather
- Carburettor replaced because the old one was damaged (replica model, strangely enough it has a screw on the side that doesn't really change the mixture much)
- valve adjustment made which i believe is right as it starts good?
- new mower blade

After these adjustments the mower starts easily and very quickly. There are no misfires or anything like that. I used it for the rest of the year but noticed more and more that something was wrong.

Yesterday I turned the mower on and wanted to mow and noticed that the symptoms had worsened. When I turn the blade on, it quickly starts to smoke slightly bluish and it seems as if there is no full power.
The blade engages normally, but when there is resistance when mowing, you notice how the engine is struggling. There is also a "wroom" noise every few seconds that feels like the engine is shaking.
The motor also makes a rattling noise, although I've seen in videos that this is probably not unusual. I then removed the spark plug and noticed that it had a black crust.
After I cleaned it, I turned the carburetor mixture screw while running the engine, but didn't notice much of a change. After a minute of running, the spark plug was crusted black again.
The oil level is exactly in the middle of the measuring scale so it is not overfilled.Unfortunately, I just don't know where to start. I don't have a compression gauge, but I was wondering whether it could be the cylinder head gasket.
But does that also explain the lack of performance? Maybe you can help me determine the next steps.

Thanks in advance and greetings

 

[Tiger Small Engine]

What is age of mower? Hours meter? Blown head gasket is a possibility. At idle, quickly accelerate to full throttle and watch for a puff of smoke, do the same from full throttle down to idle. Do this once engine is warmed up. Also, after running and warm, remove dipstick and watch for smoke coming out. A couple of good indicators for blown head gasket.

 

[lambostefan]

Sorry for the late reply. Sadly I don't know about the mower age and the hours it worked. When at idle quickly accelerating to full throttle it blows puff of smoke, the other way down to idle not. No smoke coming out of the dipstick.
I ordered a cheap set of gaskets and took the head off. The headgasket was intact but the piston and the ventiles were black. Cleaned it all up and screwed it back together with new gaskets and also new valve gasket. The cylinder walls looked very good, no damages and very smooth. What i noticed then turning the piston up and down was, that there was a slight film of oil on the walls left back. Don't know if this is normal, it wasn't really much. Set the valves again and installed everything back also carburator with new gaskets. Engine started up at first turn, but the problem persists, espacially when turning on the blade or going from idle to full speed. Seems it only happens when there is load. Also filled the engine with a new oil SAE30 only to mid of the dipstick marks. Checked crankcase breather again and blew some air in it, its absoluetly free. Any suggestions what i could do or what the problem could be?

 

[billroy1]

Yeah, There is definitely a problem there, I wish I could help. I hope more Knowledgeable people will respond, because I really want to know too. I also think I may have a Blown Head gasket on a 20 year old Briggs and Stratton 3.5 HP L head engine, the difference is that this one Blows big smoke around the head gasket area on start up but after that runs great Does that sound like a normal problem for Briggs an Stratton engines

 

[Tiger Small Engine]

Yeah, There is definitely a problem there, I wish I could help. I hope more Knowledgeable people will respond, because I really want to know too. I also think I may have a Blown Head gasket on a 20 year old Briggs and Stratton 3.5 HP L head engine, the difference is that this one Blows big smoke around the head gasket area on start up but after that runs great Does that sound like a normal problem for Briggs an Stratton engines

Would need to do a compression test and leak down test to pinpoint the issue. Many times the head gasket will be totally intact when examined (old gasket), and you need to know what to look for if it is bad. If engine is still smoking just like it was prior to replacing head gasket, obviously the head gasket was good.

 

[slomo]

Yeah, There is definitely a problem there, I wish I could help. I hope more Knowledgeable people will respond, because I really want to know too. I also think I may have a Blown Head gasket on a 20 year old Briggs and Stratton 3.5 HP L head engine, the difference is that this one Blows big smoke around the head gasket area on start up but after that runs great Does that sound like a normal problem for Briggs an Stratton engines

Usually, if it smokes on startup, it's valve seals and or guides. Smokes all the time, rings. Also be over filled with oil and several other tricks.

 

[slomo]

Hi guys,

i got a used small lawn mower last year. Since the previous owner had already tried to repair the mower, everything was no longer in its original condition. Engine model is Briggs Intek 825 (Engine No 122607-0210-E1) OHV.

Since it wouldn't start, I carried out the following repairs:

- new ignition coil because the old one was rusted - I would put the OG back on. Rust has zero to do with spark.
- Replaced crankcase breather
- Carburettor replaced because the old one was damaged (replica model, strangely enough it has a screw on the side that doesn't really change the mixture much). OEM or Chinese Amazon/Ebay?
- valve adjustment made which i believe is right as it starts good?
- new mower blade. Was it balanced prior to installing?

After these adjustments the mower starts easily and very quickly. There are no misfires or anything like that. I used it for the rest of the year but noticed more and more that something was wrong.

Yesterday I turned the mower on and wanted to mow and noticed that the symptoms had worsened. When I turn the blade on, it quickly starts to smoke slightly bluish and it seems as if there is no full power.
The blade engages normally, but when there is resistance when mowing, you notice how the engine is struggling. Do you have good compression, spark, air and fuel flow? There is also a "wroom" noise every few seconds that feels like the engine is shaking. Are the engine to deck bolts tight and present?
The motor also makes a rattling noise, Does it have oil in it? although I've seen in videos that this is probably not unusual. I then removed the spark plug and noticed that it had a black crust. Need to de-carbon the cylinder per yours and every other engine manual out there.
After I cleaned it, I turned the carburetor mixture screw while running the engine, but didn't notice much of a change. Could be an air screw. No change means that carb circuit if plugged. Leads to low power like you described. After a minute of running, the spark plug was crusted black again. Too rich (plugged air filter) and or sucking down too much oil. Sounds like she was wore out when you got it. People don't toss perfectly good mowers.
The oil level is exactly in the middle of the measuring scale so it is not overfilled. Needs to be AT THE FULL MARK all day every day. Unfortunately, I just don't know where to start. I don't have a compression gauge, but I was wondering whether it could be the cylinder head gasket. Go to your local auto parts store. They loan tools for free.
But does that also explain the lack of performance? Yes it does. Drinking oil, fouling plugs and a partially plugged carb, sounds about right. Maybe you can help me determine the next steps. Need to figure out where all the oil is going and why. Clean the carb.

Thanks in advance and greetings

 

[billroy1]

Yes, I have, I sprayed engine cleaner around the head and block What seems to be happening is that it blows smoke only on startup around the head gasket on the exhaust valve side and only when the engine is cold (It is not from oil residue) after that it runs fine I just don't know what is is but I would like to know?