# John Deere LA125



## rcsroper (Nov 22, 2013)

I sincerely hope someone is still reading this thread ...

My LA125 is operational, but it runs for about 20 minutes and then stops suddenly. I notice oil puddling below the fuel pump. Because the compression is within in specs on the low side, I have the following suspicion: Additional crankcase pressure blows oil up the dipstick tube into the fuel pump...it leaks throught the diaphragm into the carb ... I have this feeling that an electric fuel pump would be better...

Any experience with an electric fuel pump on a mower like this rather than the OEM one operated by crankcase pressure?


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## Basementgeek (Feb 7, 2005)

To my knowledge all small engine the crankcase is supposed to run a vacuum, not pressure. I would be looking a bad/dirty breather.

Look at the vent hole for gas tank, generally found on the gas cap. If it is clogged up, it acts like you describe.

BG


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## rcsroper (Nov 22, 2013)

BG...thanks for your reply. The fuel pump for this engine operates from a line connected to the top of the dip stick tube. I am guessing the crankcase pressure/vacuum must pulsate for the pump to operate.

Since the engine quits suddenly after 20 mins of operation, I am now thinking it is the solenoid at the base of the carburetor that is cutting out.

I think my oil leak is coming from the dipstick tube which fits loosely, with an o-ring seal, in the top of the engine base.

Since the dealer tells me the compression is just within spec I do not want to spend money on an overhaul ... including new rings and head gasket.

I note others have had this problem with the LA125, but there doesn't seem to be a single solution.


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## rcsroper (Nov 22, 2013)

BG...
Another thing puzzling me ... My gas cap, under the seat, is not vented. I do not see where the tank is vented at all ... what am I missing?
RCS


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## Basementgeek (Feb 7, 2005)

Will restart right back up, when dies ? 

Can't tell you on the vent, but my old rider cap has a vent hole, 3 year snow
blower does not. The vent must be how the cap cap is made, not sealing tight.

Simply check though, run with the cap off or loose.

Get that O ring replaced on the filer tube. Generally very simple fix. Remove a bolt or two pull it out, replace the ring.

BG


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## rcsroper (Nov 22, 2013)

BG
Thanks for your help. I think you are right, the cap itself is vented. I have been reading some other threads and fear now that I have a blown head gasket. I only have 164 hrs. on the machine but this model JD apparently blows head gaskets routinely.
RCS


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## Basementgeek (Feb 7, 2005)

I would not think so if it runs pretty good for a short period of time. 

If you take the head off, you got replace the head gasket any way.
They can't generally be reused.

BG


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