# John Deere LA125 Smoking, Fuel in Oil, Fuel Pump Leaking Oil



## Luv2Fish

Hi...my name is Eileen & I'm new to this site but use it often to search for info. I hope someone can assist with my JD engine troubles because I'm at a loss. 

My JD mower engine info: Briggs & Stratton 33, 21 HP OHV Engine; Model/Type/Code: 331877-0113 B1-080305ZD.

The mower started smoking (whitish/blue) like crazy; fuel pump was leaking oil & I could smell gas on the oil dipstick. Despite these issues the engine continued to run without ever stalling or sounding "off". 

I thought it was either a carb problem or blown head gasket, but, my brother-in-law, who was a mechanic, told my Dad it was a bad fuel pump so my Dad replaced it 2 days ago along with changing the oil, oil filter & air filter w/pre-cleaner. 

Smoke still blows out the muffler & this time after running the engine the mower deck & section of frame under the hood were full of "black soot". On the oil filter side of the engine it looked like oil was leaking (on fuel filter & hoses, the frame) but couldn't tell from where.

I've no idea if the following would affect the engine but thought I should provide all info. First, my Dad added Sea Foam to the oil via the crankcase & due to odor of Sea Foam I can't tell if gas is still in the oil. Second, when I started engine after work was done it sounded terrible & after a minute or so it stalled. I tried to start it again with no luck...my Dad kept trying to start it until I finally asked him to stop. I noticed that when he installed the new fuel pump he reversed the fuel inlet & pulse lines. After correctly connecting the hoses the engine finally started. I didn't want to run it due to the smoking but Dad said the engine was "cleaning itself out" so he drove it around the yard. It was after this that I saw the black soot & oil leak on one side of the engine - neither of which existed originally.

I called the JD Dealer (where I bought my riding mower) to ask about the black soot but was told he had no idea what it could be & never heard of it before. As far as the oil leak, he said it's probably the gasket where (between) the top & bottom sections of the engine are bolted together.

I'd greatly appreciate any assistance and/or feedback regarding the engine issues. I apologize for the lengthy thread!

Thanks,
Eileen


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## Wrench97

Is the oil level full or over-filled currently?

It very well may be a blown head gasket usually on the piston and valve side of the head, this will increase crankcase pressure and cause it to smoke and blow oil out.


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## Luv2Fish

Thanks for responding, Wrench97. The oil wasn't or hasn't been over-filled. It's always between Add & Fill marks or at/just below the Fill mark. 

After ruling out problems that call for engine stall, head gasket sounded right to me, too. When I had the mower picked up for repair the guy said it was the carburetor. Given the circumstances, is the carb even plausible? 

Any idea as to what caused the "black soot"? The mower deck is 42" & was covered in soot on the top & side surfaces.

Thanks again for your help...it's very much appreciated!!


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## Wrench97

Soot could be from running too rich, as in too much gas not enough air.
The reason I asked about the oil is often if the carb is flooding or the fuel pump diaphragm is leaking gas into the crankcase the oil will be over filled.
Hopefully they check it out fully before slapping on a carb


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## Luv2Fish

Okay...running too rich makes sense - thanks. 

Originally, I had fuel in the oil with lots of smoking so the fuel pump was replaced. After that I couldn't smell fuel on the dipstick - just the smell of Sea Foam because my Dad added it to the oil (crankcase) and gas tank. The guy who picked up the mower said he could smell fuel on the dipstick & when I told him it might be the Sea Foam he was smelling he made a face like, "Why the heck would your Dad put that in the oil?".

With either scenario (carb flooding or fuel pump leaking gas into crankcase), is it possible for the engine to continuously run without stalling once, even with the blades engaged & cutting the lawn? 

I was afraid dealer might replace carb without thorough check, too, so I called & put in writing that no repair work can be done without my prior authorization, as well as a phone call providing diagnostic results, necessary repair(s) & cost.


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## Basementgeek

I know Seafoam can says can be added to oil, but I would not do it. Use in the gas to help keep the fuel system clean. Does wonders for a dirty carb.

Sounds like part of the problem is with the crank case breather. Trying cleaning it first or replace it.

BG


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## Luv2Fish

Thanks for the feedback BG.......I wasn't thrilled with the idea of adding Seafoam to the crankcase - bought it to help with problems arising from ethanol fuel. I also got the spray for carb. 

Just out of curiosity, is there a specific reason you wouldn't use Sea Foam in the oil? 

Thanks, again..


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## Basementgeek

First it thins the oil. Modern day oils have more than enough additives to keep the engine clean.

Save it for the gas tank.

BG


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## Luv2Fish

I definitely wasn't aware of that....glad to know because it defeats the purpose of using SAE30 oil.

Thanks!!


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## wolfen1086

As an Shade tree mechanic once told me, modern oils have plenty of cleaners in them and Seafoam is only good for removing years of sledge left by a previous owner who didn't bother changing the oil.
As a back Yard mechanic myself I have used seafoam in the gas tank to clean varnish out of a carb or clean fuel injectors but NEVER in a crankcase.
Check the head gasket , if you have a compression tester around plug it into the spark plug hole and manually turn the engine over two times and sit back for a while and watch the needle, it SHOULD NOT drop more than one lb in 30 minutes, if it doesn't the head gasket is good. Also check the engine breather line for obstruction of breakage, replace the breather element ( if equipped), and make sure the repair facility use a new carb base gasket


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## Basementgeek

I seriously don't think you are going to find small engine that will do that.

BG


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## Wrench97

Nor a big engine compression will leak past the rings in less then a minute.


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## wolfen1086

Really? has it been that long since I used a gas powered mower that the engines have gone down hill that much? when I was a kid my grandad used to check his lawnmower with a compression tester, so it seems to my like they should still work on today's motors too shouldn't they?


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## Basementgeek

Small engine are like a lot of things, some ways better, some ways worse.

I think your grandfather was pulling your leg when it came to compression.

BG


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## Wrench97

Compression testers work like they always have, but the tester itself has a release button to let you read the highest number.


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## Luv2Fish

Thanks for all of the advice...greatly appreciate the feedback!! Turned out to be the head gasket.......the gasket, spark plug, oil & filter were changed & the mower stopped smoking. The only problem remaining, after cutting lawn, was the "soot"; however, not nearly as much as before.


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## Wrench97

Thanks for letting us the know the end result. the soot may clear after running a bit or it may need a card adjustment.


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## Luv2Fish

Sure...

Did you see my new thread, "Post Head Gasket Question"? I asked about the tech using some type of sealant in lieu of a gasket between the valve cover & the cylinder head? 

A few minutes ago I called the dealer to find out why the tech used this sealant instead of the gasket. The service manger told me, "They now use what's called a "Gasket Making Sealant" which goes on soft & then hardens into a "gasket-type seal" because they found it works better than the "old paper gaskets".

Have you ever heard of this? It doesn't make sense to me because the dealer still sells the valve cover gaskets???


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## wolfen1086

Basementgeek said:


> Small engine are like a lot of things, some ways better, some ways worse.
> 
> I think your grandfather was pulling your leg when it came to compression.
> 
> BG


Nope I watched him do it once, I've never tried it myself because to me a lawn mower engine isn't worth it, Rideing mowers maybe, but teh ones I get are the old $99 wal mart ones


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## SABL

Hi Luv2Fish......:wave:

Yes, it is normal to use a sealant in this case.....and in most cases today. Where they used gaskets years ago has been replaced by RTV sealant. I'm still trying to adjust to the stuff......I keep gasket material on hand.....:laugh:.


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## Wrench97

RTV Silicone is commonly used as gasket replacement.


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## wolfen1086

My push mower has sealant sealing the head gasket, a lot of companies are starting to use rtv type sealants more and more because they are easier to apply than holding a gasket....or so they say...I know it is cheaper sometimes, and I'd assume there's less leakage from a gasket sealer than a paper or cork gasket.
I personally prefer a solid gasket, but I'm also 50 years old and VERY untrusting of new stuff until its proved itself for more than a few years


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## Luv2Fish

Thanks for all of the feedback regarding the RTV sealant....as always, it's much appreciated. 

Unfortunately, this past weekend (2nd time using riding mower since head gasket repair) oil started leaking from the valve cover. Dealer picked up the mower earlier today so they can reseal the cover. 

I'm hoping it's only a "reseal" issue & nothing went wrong during the head gasket replacement.......it'd be just my luck?!?!

Thanks again for all of the info!!! I'll keep you posted as to the outcome of the latest oil leak


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## Basementgeek

Just a note, sealant is not used on a head gasket. 

BG


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## Luv2Fish

> Originally Posted by:* Basementgeek*
> 
> _Just a note, sealant is not used on a head gasket. _
> 
> _BG _​


Hi BG......Sealant wasn't used in place of an actual head gasket. In lieu of a valve cover gasket, the tech used "gasket-making sealant / RTV" between cylinder head & valve cover. I asked for feedback to find out if using sealant instead of a gasket was the "norm" (that it wasn't being used to cover up/hide a "screw up" or something damaged during the head gasket repair).

2nd time using my mower after head gasket repair, oil started leaking from the valve cover. Dealer picked mower up Tuesday & called today saying tech resealed valve cover w/sealant, tested (ran) it & found no oil leaking. I'll keep my fingers crossed hoping this is the last problem related to or as a result of the head gasket repair.


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## Basementgeek

Good to hear. Sealant is very good, but the thinner the metal the harder to get the seal you need.

BG


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## rcsroper

I have the identical problem with my LA125 and would like some details on your "fix" which sounds like a new head gasket.

Originally engine ran fine, but just died. It would restart, run, and die. I noticed the fuel pump leaking. I replaced fuel pump, fuel filter, checked all connections, changed the oil, checked the level, engine ran but then smokes terribly...keeps running...then smokes again. Seems like the fuel pump might be sucking oil, but connection lines are right. Maybe excessive crankcase pressure from a blown head gasket forces oil into the fuel pump.

Anyway, would like to know how the new head gasket solution worked out.

Thanks.


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## rcsroper

Took LA125 to dealer last Friday. He seemed to think it was a valve adjustment problem. We'll see ...


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## rcsroper

If anyone is still reading this thread...took my LA125 to the dealer. After replacing fuel pump, fuel filter, oil & filter, still smoked...spark plug was fouled. Seems I ran it low on oil, damaged the rings, & although the compression is still within spec it is on low side. Dealer said to just run it and keep a spare plug on hand. That's what I plan on doing until it gives up the ghost...


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## SABL

Thanks for following up on this, rcsroper........:thumb:. 

Yep, in your case, head gasket won't fix the issue of damaged rings. 

Small engines do use _some_ oil when in opertation......that's why the OEM suggests checking the oil before each use.

I check the oil first and the gas 2nd......lack of oil is damaging. Running out of gas is a pita........:laugh:. Never completely empty your gas can.....always leave enough to get the machine back to the house/shed.


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## wolfen1086

rcsroper like SABL said thanks for keeping us updated.
if you ran it low on oil then that means either you didn't check it or didn't read the stick right, so with that said, to avoid the same problem because of the same cause in the future, I don't care WHAT the owners manual says about it check the oil level BEFORE each use, I don't care how reliable an engine is, or what the manufacture says they are engineers not users, all they know is whats on paper
I've had Briggs engines go bad because of everything except oil my entire life, especially since the alcohol was introduced into gasoline.
I own three Stihl's, two chain saws and one weed eater, every two years all three need new carbs because of the gas, but luckily for me all three take the oil in the gas so I don't forget to check it cause trust me I ain;t exactly teh best at remembering to do a pre op check on stuff.LOL


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## rcsroper

Thanks guys ... you are right, checking the oil is a good idea ... duh ... I have gotten so used to mowers never burning oil having had a very old Simplicity that just chugged along forever that I never bothered with the Deere ... my bad ... Right now it seems the compression is within spec but on the low end. Accordingly, I am just keeping a spare plug on hand and letting it "rip" ... I will be watching the oil level.

One problem I have had with oil levels. You definitely do not want to overfill. For whatever reason, I had a difficult time checking the LA125. I think the cap is supposed to be all the way down when you insert the dip stick. Although this sounds elementary, it makes a big difference on the level indicator. Anyway, I seem to be off and running again ... well, after the snow clears anyway ...


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## wolfen1086

Yes on ANY engine the cap MUST be screwed all the way on to get the correct oil level reading


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## Basementgeek

Use straight weight 30 oil in it, that may help it.

BG


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