HELP Please...it caught fire

inline300

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I have a murray with a 12.5hp briggs and stratton I/C gold


I was given a mower for free, Id seen it sit in my neighbors yard for about two years now. Visually, the mower looks new. They even covered the engine.

They moved out and told me I could have it.

What I do know and have done.

Checked battery voltage. Zero.
Put air in the tires.

I jumped the mower with my other mower, it fired right up. Awesome.
Few minutes later I notice the engine begin to smoke a little.
So I pop the filter cover off and notice oil in the filter housing.
I left the cover off and fired the mower up again, and oil spewed out of the breather hose like water through a hose. Turn it off.
I check the oil, to me, it seemed the oil was over filled, excessively. so I drain it, and put in the required amount.
Fire the mower back up, it smokes but I figure this is just oil that has accumulated from an overfilled of oil. It eventually burns off and runs fine for about twenty minutes, I go to mow with it a little and all of a sudden the mower just stops moving forward, engine still ran at this point, I check into it, a pulley has destroyed itself, so I replace the pulley, fire the mower back up and proceed to mow.
All is well for ten minutes or so, then the engine begins to over rev, and a massive, thick, white cloud of smoke rolls out of the exhaust, engine boggs down.

I attribute the problem to the over rev condition, causing the oil to puke from the breather tube. So I adjust the governor down, until the throttle blade is about 1/8" open when the throttle is fully engaged. This seems to take care of the overrevving. I go mow with it, left the hood up, filter off so I could keep an eye on the carb to see if any oil began to spew out excessively.

I mow for about ten minutes once again, all is well, then I see gas shoot out of the carb and well, a little fire happened. The choke lever melted and who knows what else.

When it first give me issue, I did a compression test and got right at 50 psi cold, I know in a big 4 stroke, thats way on the low side but I have no idea what a small engine compressin psi should read, I tried to find the info online but was unable too.

I know something about big 4 stroke engines but this is the first time Ive tried to even tackle a small 4 stroke, seems they a slightly different animal.

Guess Im looking for direction. Why would oil gush out the breather hole? Why would gas have squirt out of the carb inlet?

Despite the bad, the mower cut good when it cut, everything else looks good, minimal almost nonexistant rust on the sheetmetal, paint is still shiny and new looking, seat is damaged, as the mower sat out in the weather for a couple years but it seems like it has potential.

I have no idea what a used good, or new briggs 12.5hp gold motor would run to replace or what it might cost to rebuild this one?

Any input appreciated, alot to read I know but I tried to put it all out there.

Thanks
 
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KennyV

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Hello and welcome to the group...
It sounds like you don't have too much invested in this mower so it is definitely worth fixing ...:wink:

The over full oil leads me to think you are getting raw fuel into the crank case, and then the crank is splashing it around and out the vent tube into the intake path.

Since the engine will run good for a while I'm going to figure that the rings are not badly damaged (yet)...
You have a carburetor problem allowing a lot of fuel (not just running too rich) ... You may also have an intake leak, air plus too much fuel = run away RPM...
You are definitely going to need some carb parts and might need a complete carburetor (fire is sometimes unforgiving)...


inline300 ... Ford? ... :smile:KennyV
 

inline300

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I just would not have thought of that, makes alot of sense.

I did check the oil level after this happened to see just how much oil was shot out the breather tube and did think the oil level was again unusually high.

I wasnt sure if there might be some oil passage blocked, causing a false reading at the dipstick, as I just have no idea about the internals of this engine but gas in the oil makes sense.

Is there a reputable online source for parts? Local guy is nice and all but he comes with a 30% mark up, as compared to online prices. :laughing:

Yep, my username does refer to the old ford inline engine. :biggrin:

Thanks man, much appreciated.
 

KennyV

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This is a good site to find tear down rebuild info on small engine carbs.. scroll down till you see your carb ..
Small Engine Equipment Troubleshooting, Repairs and Safety

This is one source for parts and parts breakdown identification there are several others...
Lawn Mower Parts

Can't beat free mowers... If nothing else they are a great source for parts, and often something rather simple will put it back into service...
Ford 300's were VERY good engines... :smile:KennyV
 

inline300

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Ah, I still think it was good luck. This old mower cuts and looks suprisingly good, I wouldnt hesitate to just drop a new motor in it.

They give me a push mower, said they couldnt get it to run, I messed around with it, mowed part of my yard with it earlier, so I cannot complain.

Appreciate the links Robert and Kenny, Ill check those links out.

Inline 300's are still good engines, if you can get past the fact new engines make over 400hp in trucks, gobbs of torque and just as reliable with better fuel economy...:D
 
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Bethieboo

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Wow, I would probably panic and freak out if my mower caught fire! If you can drop a new engine in to it then why not. It sounds like you can get many more years out of it once you have it fixed. Keep us posted and be careful... just in case!
 

dria

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Bethie, might I suggest that you get yourself a few fire extinguishers and practice using them. Once you have done this you might not feel so freaked out about fire.
 

DakotaMM

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Dria you make a good point. I have a lot of fire extinguishers around here but I have never practiced using one. If an emergency broke out I would have to stop and read the instructions! Thanks for the idea.
 

JDgreen

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Dria you make a good point. I have a lot of fire extinguishers around here but I have never practiced using one. If an emergency broke out I would have to stop and read the instructions! Thanks for the idea.

Why do you even have fire extinguishers if you don't know how to use them !!!!!???? :confused2:

Just pull the pin, point it at the base of the fire from about ten feet away, and squeeze the handles together. This assumes they are still charged and if they are the dry chemical type, the powder has not caked in the bottom and they do not work. Twice a year I check all my extinguishers for pressure using the gage, then turn them upside down and whack the base with a big plastic mallet a few times. And when I buy a new one, I write the date on the bottom with a big black marker and when they are ten years old, I replace the unit itself. Have the extinguishers in every building here on every floor, multiple units in the house, in every vehicle, even on my tractor, have never needed one BUT:

BETTER TO HAVE ONE AND NOT NEED IT, THAN NEED ONE AND NOT HAVE IT. :thumbsup:
 
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