Small engine question

I was mowing the grass over the weekend and the engine on the riding mower quit on me. I am looking for some assistance in determining a cause.

1. I did my usual spring tune-up and cleaning, could re-seating the spark plug cause a problem?

2. I changed the oil, could the wrong type cause it to mow a while and then clunk, shutdown and not restart?

3. I didn't see anything stuck in the blades, could moist grass cause it to suddenly die and not restart?

4. I used StaBil in the gas and added fresh, could the mixture have something to do with it?

5. I noticed something odd about the engine. (photo below)

Can you see the hole in the engine block in the center of the photo? That was punched out when the connecting rod snapped. Do you think that might be a contributing factor? (DOH!)

after reading your post thoroughly i have come to the conclusion that its probably the oil, change that and see if it runs. if that doesnt work maybe address the snapped rod...

but definitely change oil first

pinchvalve wrote: Can you see the hole in the engine block in the center of the photo? That was punched out when the connecting rod snapped.

Is that bad?

That will buff out. Just make sure to set the spark plug gap correctly.

Before you buff......

Did you forget to turn down the boost?

By George, I think you have hit on the problem.

Service advisory: While nitrous oxide may be helpful for getting through crabgrass, it is inadvisable due to reduced life expectancy of the unit.

I had a similar issue this year. See picture below. I wimped out and didn't even try JB Weld on this one.

Seeing how long a conrod that's been jb'd back together will last in a mower is exactly the sort of endeavor I expect from you, Pinchy. Carry on.

Also, autocorrect changed your name to "Punchy" at first. I almost left it under the circumstances.

I have had this happen to an alarming number of Briggs engines in my rider. Oil changed, running perfect, and BAM! BIG berkeleyING HOLE!

no warning. Just gone.

Next dead Briggs, im stuffing a honda motor in there. Im thinking d16z6.

Oh, and when the oil dipstick says 8oz of oil, that means from add to full. Not total. That engine was not briggs fault.

The briggs 12.5s from the 90s really liked to snap rods, but generally the others wouldn't unless you didn't keep oil in them. But I always run heavy oil in them, especially the splash lubed models, HD30, 15w40, 20w50 if its loose, topping off with STP if its really loose or has a knock. I also never thread in dipsticks to check unless the stick says so.

Kohler has a stronger block. But then you never know what the cause of all that thrashing around is unless you tear it down. With the powdered metal Briggs, it is sort of self explanatory so really that weak block is engineered efficiency in action. Mow-bang- engine quits-pop the hood- run down to home depot with the credit card and pick up truck. No screwing around with diagnostics.

LS1 swap time!

Timely thread. Today I changed the oil in the Briggs v twin on the mower.

I have no desire to replace that engine again. Although the first time was 50/50 my mistake and poor design of the quick drain valve.

After some disassembly, I did notice a minor issue with a connecting rod and the rod cap. It didn't look too bad, really, so I think that I will repair it. I had to laugh at the suggestion of JB Weld...as if!!!!

I don't have anything as sophisticated as JB Weld, but I have Superglue and Duct Tape...which is plenty for a lawn tractor! I will wait for it to cure properly and I should be good to go.

Don't forget to safety wire the bolts before you reinstall that piston/conrod.

I change the oil on my Craftsman mower. Mowed my grass without a problem

But then the automatic shut off and brake failed to work. shorted spark plug to shut down

Tried to pull the flywheel. One of the puller bolt holes stripped out bending the other two bolts.

Doesn't look like there is enough to drill for a bigger bolt.

Put everything back together. No start. Cut the wire to the switch. Now it runs.

Maybe after 20 years it is trying to retire.

pinchvalve wrote: I don't have anything as sophisticated as JB Weld, but I have Superglue and Duct Tape...which is plenty for a lawn tractor! I will wait for it to cure properly and I should be good to go.

Just to play it safe, I'd make sure to get a couple zip ties around the duct tape....you know to hold it all together.

Thanks for the suggestions. The motor is from 1982, and things were stronger back then, so I am going to use Nitromethane instead of gas to make sure it starts easily.

trucke wrote: Did you forget to turn down the boost?

Its not a rotary!

Well, I tried to start it up today. I thought that the Nitro and half a can of starting fluid would do the trick, but it might have been too much.

Mower Startup

In reply to pinchvalve:

After watching that video, "MegaDork" seems a fitting title for you.

I still chuckled.

Aw man, you have most of the office laughing at that one!

Thanks