Too much Oil - But I survived

[lefty]

Scotts Mower: 21595x8B
Briggs: 121682-0122-E1 Code:990513F

This came in from my brother-in-law as running before a big puff of white smoke and then no start. He reported the same problem from last week.

Ignition check was good with good spark.

Compression check: I put my thumb over the spark plug hole and asked by brother-in-law to pull her over for a preliminary compression check... a 4 foot long firey flame of hell came blowing out of the cylinder igniting the machine and my entire right arm. I ran around the garage beating my arm against my leg trying to put out the flames, eventually, pulling my sweatshirt off to save my own life. I learned something today...and got a good laugh at the same time. The machine was obviously flooded and once the fuel burned off me, I was good as new...just a burning on my hand every 15 minutes, which was alleviated by some cold water. I'm thinking 1st degree as I have no blistering or peeling.

So I obviously had fuel delivery.

Checked the oil and it was way overfilled. Maybe 8-10 oz extra. I drained it to its optimal level. The air filter was soaked with oil. Once I pulled the air filter, it started right up. As soon as I installed the air filter, it would stall immediately. Problem solved.

My question is, aside from draining the excess oil out and replacing the air filter, is there anything else I should be concerned about regarding the machine running for a certain amount of time with too much oil?

[KE4AVB]

Glad you're Okay but you know to be more careful next time. This is why I ground the ignition coil kill when clearing the cylinder. I usually clear the cylinder then use a compression gauge for a rough test of cylinder condition.

As just draining off part of the oil is not enough, you should do a complete oil change including the filter on models with filter as the oil is diluted and will cause engine failure. Now it depends how long it has been running with the diluted oil as if the there metal transfer from the rod to crankshaft. This something that can come back to haunt you; just your customer that this is a possibility or you can pull the crankcase cover and check the crankshaft journal for transfer. Even diluted oil is better than no oil so damage can be minimal. I have just drained and replaced the oil then the leak source without problems on most engines.

The root cause is a leaky carburetor needle and seat. Sometimes from just being stuck or trash between them, other times lacking sealing otherwise. Now on the Nikki carburetor it can also be the fuel bowl gasket set. The Nikki requires a good gasket with no nicks.

BTW even with first degree burns there can be peeling later and sweating doesn't help for the salt will burn if there is an open area.

[lefty]

Thanks KE. I definitely learned my lesson. So you're thinking that the excess fluid in the crankcase may be due to faulty carb leaking fuel into the crankcase? Should I be able to smell fuel in the oil? Just from a diagnostic standpoint. I will definitely change the oil. Do you think I should pull the carb and give it a looK?

[KE4AVB]

Thanks KE. I definitely learned my lesson. So you're thinking that the excess fluid in the crankcase may be due to faulty carb leaking fuel into the crankcase? Should I be able to smell fuel in the oil? Just from a diagnostic standpoint. I will definitely change the oil. Do you think I should pull the carb and give it a looK?

Yes to the first question.

It may just be me but I can't tell by smell; but it will thinner than normal.

You can just loosen the carburetor from the intake if the design will allow and see if fuel is flowing out. Now for me since I have Mityvac pressure tester I pull the carburetor, invert it, and do a pop test test to see if carburetor will hold 5-9 psi. Most will pop off at around 10 psi; otherwords, the needle will release at this pressure and allow air to flow. When you don't have the tester you can rig a tank and bench test the carburetor in normal position awhile checking for leaks. Most carburetor won't right away as it takes time to overflow the fuel bowl. This what I did for several years until I could afford the Mityvac. There was just a greater need for other more used tools at the time.

[lefty]

I think I get it. So if I remove the carburetor, connect it to my fuel cell at my bench and see if it holds. If fuel starts to pour out then I know my needle is not seating correctly. If nothing unusual happens, then it's probably just a case of the last knucklehead putting in too much oil?

[KE4AVB]

Pretty well covers it. Now I have seen that some carburetors would only leak overnight on the bench so if you can give it a few hours test under the simulated conditions.

And yes I have seen these engines overfilled too by the operator. This can throw your off thinking that you got a fuel leak but it is better to play it safe and test, if nothing else for your own peace of mind. Usually overfilled by following misprint owners manuals or when the operator changes the oil and don't get that manual said up to a particular amount. Don't see it very much though as most comes in with very little oil and with it more like black strap molasses.

[Fulltilt]

I think I get it. So if I remove the carburetor, connect it to my fuel cell at my bench and see if it holds. If fuel starts to pour out then I know my needle is not seating correctly. If nothing unusual happens, then it's probably just a case of the last knucklehead putting in too much oil?

Look, you don't need to do all that, what for? The flooding, the oil...
Just get a needle /seat and install it, problem solved! Remember, groove down , lube up the edge of the seat will help it slide down, and be sure its fully seated.
Probably will need a bowl gasket. I usually grease the rim of the body and bowl to aid assembly and to make for easier removal. Don't forget to clean the main jet/bowl nut.
Another tip: don't go crazy with the blow gun on the carb exterior or you will destroy the foam seals. If your going to get a rebuild kit, then all them parts are in it, but I just stock the seats, bowl gaskets and a needle or two. Be careful with the bowl nut gasket, them suckers are expensive.

[Arkie]

I also add a fuel cutoff valve whenever equipment (fuel feed layout) allows use of such.

Subject: Safety: Grounding the spark plug wire to prevent spark/fire.

I always ground the spark plug wire. I had a flooded chainsaw catch fire when cranked while I was holding it between my legs with the spark plug removed and the plug wire not grounded. Lucky that my pants did not get on fire in that area.

Every time I remove a spark plug to check anything I'm automatically reminded of that close call and the spark plug wire gets grounded or the kill switch is checked as being in the off position..

[KE4AVB]

Yes Fulltilt these carburetors on the 121682-0122-E1 has replacement rubber seats. The Op is learning the troubleshooting process and this will teach how to verify if it was leak or not. This should give peace of mind knowing if there was an actual leakage problem instead just guessing and have the engine to come back again for the same problem. It can be simple case of just overfilling which in case then the operator needs to show the correct level to check for.

Especially important to learn this as there are carburetors with metal seats that if are leaky with even a new rubber tip needle valve is installed will need a good cleaning with a 6 point 61 degree finishing countersink. And no not just any countersink will work as there are different styles and pitches. I know some recommend just using toothpaste or fine valve grinding compound on a cotton swap but this will not remove material evenly and can actually make things worse. Now if the metal seat is just dirty it will work but will not correct scratched seats. Even the countersinking can be over done and the float will sit too high. Also the inverted pressure test will test those replaceable needle seats for leakage around the outside mating areas in which the seat will need replacing.

[KE4AVB]

I also add a fuel cutoff valve whenever equipment (fuel feed layout) allows use of such.

Subject: Safety: Grounding the spark plug wire to prevent spark/fire.

I always ground the spark plug wire. I had a flooded chainsaw catch fire when cranked while I was holding it between my legs with the spark plug removed and the plug wire not grounded. Lucky that my pants did not get on fire in that area.

Every time I remove a spark plug to check anything I'm automatically reminded of that close call and the spark plug wire gets grounded or the kill switch is checked as being in the off position..

Yes lessons like this seems to one that all us must learn the hard way sometimes. Better safe then sorry later.

I my worse case of fire was when I was working a Victor calculator and spraying pressurize lube on the gear train. Just a flash fire but enough to wake you up. The motor governor had ignited it, ignited the towel under the unit, and I lost most the hair on my hands. Of course the towel was thrown away after I put the fire out and the hair grew back. Ever since I have been extra careful around flammables.