Poorly John Deere 7700
Discussion
Silent1 said:
The Excession said:
What's up with the 7700? I might be able to help.
Feels like a fuel starvation issue.It's got a bit rattley of late, it's hunting at idle and it's not making the power, at a guess it's only making 120hp whereas this time last year it was nearer 180hp, it's not able to do much more than 4kmh with a 5 furrow plough with mouldboard splitters.
The only thing that's changed is some tool managed to overheat it 6 months ago moving from one farm to another, i suspected the head gasket, but the oil/coolant and hydraulic levels are fine, but the hydralic pressure is low (shuttle gears are jumpy and the auto clutch control is bloody sharp)
What's the status with the fuel filters? Has it been run on dirty diesel (any water in the sight bowls)? When were all the filters last replaced?
Is there much black smoke out of the exhaust (idle and under load)? Any indications of over heating now? Any sludge in the coolant?
You're on the same line as me.
I'm ditching the fuel filters off it tomorrow, then i'll get in there with the airline.
I'm suspecting water/crap in the fuel tank as when i parked it up last october, i left it perfect and it's only done 50 hours since, but it was driven by a guy who'd never been in a tractor before and has no mechanical sympathy, so it's going to be something simple i hope.
It's had no water in the filters though, coolant is fine. Exhaust isn't smoking more than usual, but it is smelling more diesely, it's usually pretty clean.
It's running warm for the temperature, whereas it should have been in the lower 1/3rd it's sitting around 2/3rds.
As for the rattle, i'm suspecting either the turbo or something serious like a big end bearing as until i can find out what the bloke broke and has been replaced i can't even seriously start pulling it apart.
I'm ditching the fuel filters off it tomorrow, then i'll get in there with the airline.
I'm suspecting water/crap in the fuel tank as when i parked it up last october, i left it perfect and it's only done 50 hours since, but it was driven by a guy who'd never been in a tractor before and has no mechanical sympathy, so it's going to be something simple i hope.
It's had no water in the filters though, coolant is fine. Exhaust isn't smoking more than usual, but it is smelling more diesely, it's usually pretty clean.
It's running warm for the temperature, whereas it should have been in the lower 1/3rd it's sitting around 2/3rds.
As for the rattle, i'm suspecting either the turbo or something serious like a big end bearing as until i can find out what the bloke broke and has been replaced i can't even seriously start pulling it apart.
Not teaching you to suck eggs, as it's evident you know what you're at. 
Still, some more thoughts...
50 hours since last October is very light use, old fuel having stood for so long?
I'd start as you say, replace the air & fuel filters and also get fresh fuel in there. Even drain the tank if it's nearly empty.
After that, I guess it's get the injector pump checked (and hope it doesn't need a new one
). It's not been run on biodisel or anything daft like that has it?
I know what you mean with monkeys driving these things, just because it is big doesn't mean it's a go anywhere do anything tank. I'm amazed at the lack of driving skills and mechanical sympathy of some of the lds out there. You know the type, no ear for what the machinery is doing so that when something starts to go wrong they carry on regardless and turn what could have been a simple fix into a full on strip and refit.
Aside, I'd have hoped to be out with the silage contractors by now, but the weather has been so s
te there's no growth here, I think it's going to be another two weeks yet even if we get a good spell of warmth... depressing stuff.
Still, some more thoughts...
50 hours since last October is very light use, old fuel having stood for so long?
I'd start as you say, replace the air & fuel filters and also get fresh fuel in there. Even drain the tank if it's nearly empty.
After that, I guess it's get the injector pump checked (and hope it doesn't need a new one
). It's not been run on biodisel or anything daft like that has it?I know what you mean with monkeys driving these things, just because it is big doesn't mean it's a go anywhere do anything tank. I'm amazed at the lack of driving skills and mechanical sympathy of some of the lds out there. You know the type, no ear for what the machinery is doing so that when something starts to go wrong they carry on regardless and turn what could have been a simple fix into a full on strip and refit.
Aside, I'd have hoped to be out with the silage contractors by now, but the weather has been so s
te there's no growth here, I think it's going to be another two weeks yet even if we get a good spell of warmth... depressing stuff.
Hi guys, just followed your thread from the lounge. Hope the JD gets fixed, S1. Just like to say it's great the way PH works..
You both find something mutual to discuss and move off to your own area to chat further. Just shows in an age of overpowering hi-techery a computer can be quite useful!
Adrian, just read your profile, spent the last 7 years with a girl from your neck of the woods, shame it's ended. Ah, such is life. Her brother is a sound man, with a dairy herd in the 'mines. I miss it all. Anyway, UP TIPP! A great county ye have.
You both find something mutual to discuss and move off to your own area to chat further. Just shows in an age of overpowering hi-techery a computer can be quite useful!
Adrian, just read your profile, spent the last 7 years with a girl from your neck of the woods, shame it's ended. Ah, such is life. Her brother is a sound man, with a dairy herd in the 'mines. I miss it all. Anyway, UP TIPP! A great county ye have.
John Deere I know heavy equipment whose heavy duty performance is relatively good. Perhaps it needs flushing oil although it has less than 50 hours of use, it is not recommended to use lubricant more than 6 month of use. Although it is still within drain interval, oxidation during that period might decrease its function lubricating the engine. Make sure the clutch and tires are in good condition.
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