2350 hard start after running

[Tx Jim]

TDIdog
1st thing that needs to be clarified is if your tractor has poppet or spool scv's. Which type control valve does your tractor have(top or bottom)?

PS: I'm not convinced the scv's on your tractor are causing it's hyd problems. I'll suggest to get a 5000 psi gauge with a short hose & male coupler & check pressure on each breakaway coupler & note if pressure falls when control lever is returned to neutral & how quickly it falls.

 

[Tx Jim]

You are correct Jim. Most 50 series we sold had the more deluxe poppet valves, so it slips my mind sometimes that the spool valve is a possibility. At that ime period, most spool valves were on government bid situations. The spool valves were cheaper, so they were spec that way to compete with other brands that didn't have the "deluxe" poppet valves. Today, the spool valves are the norm. Deluxe valves are electronic controlled spool valves. Makes you wonder what "improvements" we will see next. Scary at times.

I agree most utility models I've seen have the poppet valves. Have you ever set or witnessed adjusting poppet valves utilizing air pressure instead of dial indicator?

 

[TDIdog]

TDIdog
1st thing that needs to be clarified is if your tractor has poppet or spool scv's. Which type control valve does your tractor have(top or bottom)?

PS: I'm not convinced the scv's on your tractor are causing it's hyd problems. I'll suggest to get a 5000 psi gauge with a short hose & male coupler & check pressure on each breakaway coupler & note if pressure falls when control lever is returned to neutral & how quickly it falls.

It definitely has poppet valves. That is the square block just below the leaky shift levers. 100% sure on this. I looked through the parts manual once you guys started discussing poppet valves, and it is poppet valves.

I also bought a tech manual PDF and have had a quick look at the poppet valve rebuild procedure and I am wondering if the poppets can be resealed without messing with the adjustments. According to the tech manual, the poppets come out, then the rocker plate, so it would seem like this could be done. Or does removing the valves require an adjustment afterwards? Also, is the plate required to adjust them?

 

[Tx Jim]

I also bought a tech manual PDF and have had a quick look at the poppet valve rebuild procedure and I am wondering if the poppets can be resealed without messing with the adjustments. According to the tech manual, the poppets come out, then the rocker plate, so it would seem like this could be done. Or does removing the valves require an adjustment afterwards? Also, is the plate required to adjust them?

SCV rocker requires adjustment if poppet valves are replaced. I'm going to explain 1 more time "YOU NEED TO PERFORM GOOD HYD DIAGNOSTICS BEFORE REPLACING ANY PARTS. I served as a JD dealer service manager from '74-'87 so please listen to my hyd experience.

 

[pmsmechanic]

To TDIdog: You've got TX Jim helping you out with this. If you use his experience you will save money. Don't throw his help away.

 

[Zebrafive]

SCV rocker requires adjustment if poppet valves are replaced. I'm going to explain 1 more time "YOU NEED TO PERFORM GOOD HYD DIAGNOSTICS BEFORE REPLACING ANY PARTS. I served as a JD dealer service manager from '74-'87 so please listen to my hyd experience.

I would isolate the SCVs from the hydraulics (disconnect the feed line and cap or plug) before taking the SCVs apart. See if that makes any change.

 

[TDIdog]

SCV rocker requires adjustment if poppet valves are replaced. I'm going to explain 1 more time "YOU NEED TO PERFORM GOOD HYD DIAGNOSTICS BEFORE REPLACING ANY PARTS. I served as a JD dealer service manager from '74-'87 so please listen to my hyd experience.

Yes Jim, I understand the need to do comprehensive troubleshooting. But, I'm still trying to get a feel of what MAY be wrong so that I can do THAT troubleshooting, as well as understanding what I MAY have to do before I decide if I will dig into this or pass on it. I understand that you are highly experienced in these systems and I appreciate your help, but please, also understand that I'm not inexperienced in heavy mechanics myself. I spent 15 years at a John Deere construction dealer from 1993 to 2008 and have been working as an independent since then. Do I know specifics about everything? Absolutely not, but I don't have an ego that prevents me from asking for help or even passing on a job if I feel it's in the best interest of all. I am a pretty good hand with a wrench with a high capacity to learn, even though I'm not a young buck anymore.

I have been tied up with other projects right now, so when I can break free, I will plug into the coupler and, after re-reading you post, will check standby and watch pressures as I move the levers to neutral as you suggested.
There is also a recommendation that I isolate out the Poppet valve and see how it starts then. I don't see any problem with this since it is a closed-center system. Do you agree that this would be a valid and safe test?

I don't have the correct quick coupler to get into the work ports on the back of the tractor. I'm sure because I don't work on Ag stuff very often. Do you know the specific name for that style coupler so I can get that before I make a trip out there? I have piles of adapters that have acquired and relocated over the years, so once I get the coupler, I'm sure I can fabri-cobble something to my hoses and guages.

 

[Tx Jim]

Please don't take offence as I didn't understand you had previous mechanical experience.

I agree with Zebrafive to disconnect & plug the pressure line that supplies oil to scv. Isolating a suspected ailing hyd function when possible to do so from hyd system is a good diagnostic tool. It will surprise me if a faulty scv poppet is causing engine to be difficult to start. JD 50 series should require what's refereed as ISO male coupler tip. Photo of coupler tip is from Surplus Center. What type valve controls frt end loader? I'll advise to isolate FEL control valve from hyd system.

 

[TDIdog]

I would isolate the SCVs from the hydraulics (disconnect the feed line and cap or plug) before taking the SCVs apart. See if that makes any change.

Thank you for the suggestion. I know the line to the loader comes off the back side of the poppet valve block and I seem to recall a hard line just above it. I have the manual, so I can always check that to be sure.

One thing I have in my favor is that this problem is consistent rather than intermittent. That's always a good thing.

 

[TDIdog]

Please don't take offence as I didn't understand you had previous mechanical experience.

I agree with Zebrafive to disconnect & plug the pressure line that supplies oil to scv. Isolating a suspected ailing hyd function when possible to do so from hyd system is a good diagnostic tool. It will surprise me if a faulty scv poppet is causing engine to be difficult to start. JD 50 series should require what's refereed as ISO male coupler tip. Photo of coupler tip is from Surplus Center. What type valve controls frt end loader? I'll advise to isolate FEL control valve from hyd system.

So decided to run the Beetle out to the tractor. 40MPG > 11 MPG AND I don't have to climb in the passenger door.

Anyway, if I have this right, it looks like the pressure hose into the poppet valve goes in between the valve and the trans. That hose goes into a block on the side of the trans just above the filter and that block has a hard line going forward. It'll be easier to isolate the FEL valve, so I'll do that first, but where is the best place to isolate the poppet? Going into that block or coming out of it? I feel it's coming out of it, but would rather not somehow bust a window in something.

The FEL is a JD 540. Looking through the holes in the box housing the loader control valve, it looks like a spool valve.

For some reason I can't open attachments on my phone, but I got a look at it and I have a good gauge on the size so I can go from there.

On my way out here, I was thinking about the hard to start as well. By turning the steering wheel we are flowing relatively low pressure oil, making it easier for the engine to turn over. So, it seems like the only way that a poppet could cause this is if a pressure poppet was open ... No, that would deadhead and destroke the pump. Hmmm. I'm sure I'm missing something here.

So if it's not a downstream hydraulic problem, what about the pump?

Or, as was mentioned early bad grounds? When I was here before, it started fine first thing but now it's slow cranking. Both batteries ground to the battery box. I think I need to go this direction first now that I see it cranking slow. Block heater is warm and charger is on it. Next time I come out, I'll start there even though the owner has said it starts fine the first time.

To be continued...