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Discussion Starter #1
Hi all. For the past couple years, my JD GX345 would occasionally belch some white smoke out the exhaust. This was more noticeable in the colder months, esp when using the snowblower.
It smelled kinda like burnt rubber, so at first I thought it had something to do with the SB belt slipping, but the color wasn't black. Well, it's gotten progressively worse,
Today I pulled the plugs and found the LEFT one had "moisture" on it. Kinda hard to see from this pic, but both plugs were not in the best condition.
There's not been very much loss of coolant tho', so it still makes me wonder.

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I have the service manual and it looks pretty straight forward. Is there any thing to be aware of when replacing the head gasket(s) on this engine ? And, where's the best place to get a gasket kit...JD dealer?

2443456


Thanks, gatz
 

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What I see looking at those plugs is a very rich mixture. Lean out the carb.

Replace the plugs and adjust the carb.

When you adjust the high speed jet close it all the way, then back it out to 1 and 1/2 turns. Start the engine and adjust for smoothest running performance. If the engine surges the mixture is too lean, so open the jet until the engine runs smoothly.

You can check the ratio by covering the exhaust with your hand and then smelling you hand. Smell gas?? Too rich. All old school, but it always works.
 

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Discussion Starter #3
OK, I'll do that first.
But, as I said, the left plug was "wet" with moisture, not gas.
Hard to see that in the pic
 

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What I see looking at those plugs is a very rich mixture. Lean out the carb.

Replace the plugs and adjust the carb.

When you adjust the high speed jet close it all the way, then back it out to 1 and 1/2 turns. Start the engine and adjust for smoothest running performance. If the engine surges the mixture is too lean, so open the jet until the engine runs smoothly.
The high-speed jet is fixed on this engine.

Hard to tell with 100% certainty from Denver, but those plugs look oil-fouled to me. How is your oil consumption?
 

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Discussion Starter #5
The high-speed jet is fixed on this engine.

Hard to tell from Denver, but those plugs look oil-fouled to me. How is your oil consumption?
I agree, they do have a burnt oily look to them, but the engine doesn't use oil.
When I pulled the Left side plug, it was "wet". When I rubbed it off, it had no smell to it.
Since my last post, I made an adapter with a regulator to pressurize the cylinders @ 60 psi.
When it was applied to the Right cylinder, nothing of note.
When it was applied to the Left cylinder, there was definitely air-flow back to the intake.
I placed a paper towel over the intake and checked it....no smell, but it did look like a light mist.
I also cranked the engine with cylinder pressurized & the paper towel over the intake; same thing.

I'm hoping I don't have a cracked head.
Tomorrow when it warms up a little, I'll dig into it more.
Thanks for the comments and advice.
 

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I agree, they do have a burnt oily look to them, but the engine doesn't use oil.
When I pulled the Left side plug, it was "wet". When I rubbed it off, it had no smell to it.
Since my last post, I made an adapter with a regulator to pressurize the cylinders @ 60 psi.
When it was applied to the Right cylinder, nothing of note.
When it was applied to the Left cylinder, there was definitely air-flow back to the intake.
I placed a paper towel over the intake and checked it....no smell, but it did look like a light mist.
I also cranked the engine with cylinder pressurized & the paper towel over the intake; same thing.

I'm hoping I don't have a cracked head.
Tomorrow when it warms up a little, I'll dig into it more.
Thanks for the comments and advice.
That is the cylinder head (left side from setting on the seat) with the thermostat in it, and is noted to cause (leak) coolant into the combustion chamber.
 

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Discussion Starter #7
That is the cylinder head (left side from setting on the seat) with the thermostat in it, and is noted to cause (leak) coolant into the combustion chamber.
Been,
Thanks for the response.

The thermostat housing gasket is leaking? Is this how the pressurized air is getting into the intake ?
Replace Item 21 ?

2444327
 

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If that’s the case, might as well toss a new thermostat in there while you’ve got it apart.
 

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Discussion Starter #9
Popped the Left head off yesterday. Can't see anything wrong. Head gasket was OK; no missing/damaged parts of the metal sealing ring.
No obvious fracture lines in the casting. I've yet to take off the valves for a look inside the IN & EX ports.... might have to make a valve-spring compressor.
Still cannot figure out how pressurizing the cylinder resulted in air being leaked back into the intake and forming a slight mist.
 

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Popped the Left head off yesterday. Can't see anything wrong. Head gasket was OK; no missing/damaged parts of the metal sealing ring.
No obvious fracture lines in the casting. I've yet to take off the valves for a look inside the IN & EX ports.... might have to make a valve-spring compressor.
Still cannot figure out how pressurizing the cylinder resulted in air being leaked back into the intake and forming a slight mist.
We know for sure the way those spark plugs look, you have some bad valve guide seals. But, that not what causes the coolant leakage.
 

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Discussion Starter #11
Update on the GX345. (Man, I feel dumb. )

Took the heads off and had them Magnafluxed. No issues. Dressed up the valve surfaces and lapped them to their respective holes.
The intake valve on the Left head was letting air escape back into the intake manifold; which answered that question.
So, actually, it was a good thing to pull them off.

Got all new gaskets and assembled the heads & intake manifold to the engine. When I put the carb back on, I noticed that the limit cap was missing.
I have no idea who did that, but it was that way when I bought it.

BTW, what is that small stem sticking out to the right....looks a little bent. Maybe it got that way when whoever broke off the limit cap.

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@oldgibsonguy had it nailed. The engine was running too rich.
My sense of smell must be deteriorating.

Now, the question is "can I just turn the adj screw in all the way, and then back off 1 1/2 turns ?" Will that get it?
It's really a bear to get at that screw with the air ducting on.. I might have to make an extension to clear, but still be able to turn it.
I see a few places that sell a carb for the FD611V engine, so I could go that route as well

Thanks for all the help and advice. I really appreciate it.

gatz
 

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Update on the GX345. (Man, I feel dumb. )

Took the heads off and had them Magnafluxed. No issues. Dressed up the valve surfaces and lapped them to their respective holes.
The intake valve on the Left head was letting air escape back into the intake manifold; which answered that question.
So, actually, it was a good thing to pull them off.

Got all new gaskets and assembled the heads & intake manifold to the engine. When I put the carb back on, I noticed that the limit cap was missing.
I have no idea who did that, but it was that way when I bought it.

BTW, what is that small stem sticking out to the right....looks a little bent. Maybe it got that way when whoever broke off the limit cap.

View attachment 2447231

@oldgibsonguy had it nailed. The engine was running too rich.
My sense of smell must be deteriorating.

Now, the question is "can I just turn the adj screw in all the way, and then back off 1 1/2 turns ?" Will that get it?
It's really a bear to get at that screw with the air ducting on.. I might have to make an extension to clear, but still be able to turn it.
I see a few places that sell a carb for the FD611V engine, so I could go that route as well

Thanks for all the help and advice. I really appreciate it.

gatz
That "screw" you are referring to, is the "rich and lean" mixture needle, and someone has removed the black limiter cap on it. I would do as you have said...turn it out 1-1/2" turns.
I made a minor change to my '99 345 with the FD611V engine, that I drill a 1/2" hole in the air duct housing so I could make the adjustment with a foot or more long screw driver.
That "black limiter cap thing is there due to the California Smog law that was passed many years ago and has been a troublesome thing since.
 

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Now, the question is "can I just turn the adj screw in all the way, and then back off 1 1/2 turns ?" Will that get it?
It's really a bear to get at that screw with the air ducting on.. I might have to make an extension to clear, but still be able to turn it.
I use a 1" length of 3/16" vacuum hose on the end of a long Phillips screwdriver to adjust the mixture screw on my GX345. It should fit snugly over the knurled portion of the mixture screw.

The Deere procedure for adjusting the mixture is to:
  1. Turn slow idle speed screw until slow idle speed is 1500 - 1800 rpm.
  2. Adjust idle mixture screw for the highest engine speed.
  3. Turn slow idle speed to get and idle speed of 2050 +/- 150 rpm.
If not obvious, the engine should be fully warmed up.

Note that is the low-speed adjustment, the highspeed jet is fixed. It does impact the overall high-speed mixture.

If you buy a new carb, you'll need to adjust that one too so you might as well try adjusting this one.
 

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Discussion Starter #14
Messed around making an access in the air ducting (like Been There had done) and an adapter so that I could turn that screw in/out. But when I turned the screw all the way in, it just kept on turning.
Found out that the threads in the carb body were stripped. So that's how so much gas was getting in.
Bought an OEM Kawasaki carb, set the high-idle screw to the max allowed by the limiting cap & installed the carb.
After getting it running, adjusted the low idle.
It runs great !
Thanks to all who helped.
gatz
 

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It has been mentioned on here many times that when a Kawa runs poorly and the obvious things have been tried, buy a new carb. I've bought about four or five for that engine and it saves a lot of time. BTW, I have never had to tune one after I replaced it with a new one. Right out of the box they run great.
 
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