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John Deere LA105 Smoking

#1

fladjb

fladjb

I have a John Deere LA105. I used it on Saturday and for the past two weeks with no problem. Yesterday when I went to start it, it seemed like I had left the lights on a drained the battery. I had to jump it from my truck to get it running. I blow a large amount of white smoke which I figured no big deal. It then shut down again. Started it again and more white smoke and shut down after only a few seconds. Did it a few more time in low idle and fast idle with same results. It was not on it's side or turned over. The gas cap is new and seems fine and although the oil may be a little high it's been running fine. I just changed the oil and put in a new air filter along with new fuel filter and pump and spark plug a few weeks ago. Everything's been running fine it just happen all of a sudden. Blow head gasket? Stuck carb needle? what do you think.
Thanks


#2

BlazNT

BlazNT

Blown head gasket or stuck values. Both are in the same place.


#3

7394

7394

A blown head gasket, you should be able to hear the leak when cranking it..

What does the spark plug(s) read like ?

You say you just changed the oil & it's now overfull. No problem prior.. How much overfull ?


#4

fladjb

fladjb

7394 said:
A blown head gasket, you should be able to hear the leak when cranking it..

What does the spark plug(s) read like ?

You say you just changed the oil & it's now overfull. No problem prior.. How much overfull ?

Emptied the oil last night, smelled a little gassy. Started it for a second without oil and did not smoke to bad. Put oil back in it and started smoking bad again. Also saw oil spitting out the muffler but heard no leak sounds. Probably blown in between piston and rod housing in the middle were there is no bolt. Have not pulled plug yet and it was overfilled by about 1/8 above full on stick. Going to order the gaskets and pull it apart this weekend. Figure all I need is valve, head and manifold gaskets correct? What do you think the possibility of rings being a problem. Seems to still have great compression but not tested.

Thanks for the replies by the way.
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#5

7394

7394

Strange it just happened after your oil change.. Are you running a straight weight oil like 30wt ? 1/8" over full is not recommended, but I don't think that was the cause.

As to doing a compression test, that can be tricky.. As most bigger mower engines have compression releases designed into the cam profile. & just spinning it by the starter will give a false (low) reading. So the engine will start easy & not tear up starters..

This is important to know also to set your valves, you don't set valve lash @ TDC, but in most cases after finding TDC, rotate engine clock-wise 1/4" past TDC to get off the comp releases..


#6

fladjb

fladjb

7394 said:
Strange it just happened after your oil change.. Are you running a straight weight oil like 30wt ? 1/8" over full is not recommended, but I don't think that was the cause.

As to doing a compression test, that can be tricky.. As most bigger mower engines have compression releases designed into the cam profile. & just spinning it by the starter will give a false (low) reading. So the engine will start easy & not tear up starters..

This is important to know also to set your valves, you don't set valve lash @ TDC, but in most cases after finding TDC, rotate engine clock-wise 1/4" past TDC to get off the comp releases..
Click to expand...

I pulled it all apart last night. Could not really tell if the gasket had blown because it all came apart when I pulled the head off. In reply to above I'm a little confused now. When I put this all back together, after my parts come in, I thought all I would need to do is put the new gasket on and put the rods back in place and tighten down. Do I need to take the rockers off and alien the piston a certain way first? I know the steel rod is for exhaust and the aluminum rod is for intake but other than that I though it was straight forwarded. By the way it did not look bad inside the cylinder, a little carbon but it cleaned right off. No scoring on walls and rods look fine and straight.


#7

7394

7394

Sorry for the confusion, if you haven't touched the rocker settings (sounds like you have not) & your NEW head gasket is gonna be same thickness, you should be ok there, with out adjustment, just re-assembly as you planned..

However, I would suggest once complete head is back on & torqued down, (with spark plug removed) rotate engine by hand (clock-wise looking at it) & make sure it spins freely, while rotating it grab a rocker & see if you feel a little free play at a certain position, as it spins.. Then try the other ..

Hopefully the head gasket is the issue.. You didn't mention seeing any oil on piston top..





If you keep this mower long enough, you will likely have to set the valve lash to the required specs..


#8

M

motoman

The "read" the plug may refer to color and residue on the plugs. Consult any auto repair manual for a starting point. Can help you consider oil burning, over rich or lean. Read after fully warm, no choke.


#9

7394

7394

motoman said:
The "read" the plug may refer to color and residue on the plugs. Consult any auto repair manual for a starting point. Can help you consider oil burning, over rich or lean. Read after fully warm, no choke.
Click to expand...

Precisely, Thank You Motoman !!!


#10

fladjb

fladjb

Well thank you to all for your replies. It was the head gasket. Repaired it and started right6 up no smoke. It did start hard after a couple of time using it and at one point it was running then almost stalling and puffing a little black smoke all about every 20 seconds but then the next day it was fine. A little confusing but I may have a build up or something in my carburetor float area. I have yet to open it up. Kind of thought that's what the gentlemen meant about the plug read. The new one was really black after I was done so I put the old one back in. Ill get another new one soon. Top of the piston was just a little brown from carbon.
Thanks again to everyone who replied. Very helpful


#11

7394

7394

Black on the spark plug is carbon, would suggest trying adding some Seafoam* to the Gas.. That can help clean out the carb..........


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