430 Running Rough

Richard · May 13, 2023

Other day, I was mowing. Machine starts on a click.... runs fine. I was done mowing, suddenly it started to run VERY rough. Much like maybe an auto would run rough if you choked the carburetor down some (I know this is fuel injected diesel).

Still... if the car is running and you start to choke it, it might start to run VERY rough until you open the throttle (turn choke off). This hobbled home, engine died. Started up, ran again, VERY rough....hobbled....died. Restarted, ran VERY rough....so I sat there. It had a terrible idle and I thought I might be able to make some progress closer to home, closer to the tools.

Suddenly it cleared up and roared like the engine should.

I'm intrigued. Going over in my head what it might be, get it to outside garage and stop engine. Yesterday, jump on to cut yard and again ROUGH ROUGH idle. Blackish (a light tint) coming out of exhaust, it will NOT start. I'm tinkering on this for about an hour (hook battery to charger to keep battery going).... every now & then it DOES start to idle but again, a VERY ROUGH idle, then dies.

I'm working 12/14 hours a day and today, had a wedding to attend so I've not had time to get dirty.

I did wonder, is the air filter clogged (no) then realized if it was clogged, it woudln't have perked up again the other day.

I'm guessing fuel. This has a water seperator (if I recall) bolted to the firewall. I'm guessing this is also the fuel filter. Has two screws that remove. I'm guessing one for bleeding and the other for draining.

Red diesel came out of both of them.

That's about as far as I got. Sunday and Monday I'm going to be off. If it doesn't rain, I can dig into this a bit. Thought I'd ask for ideas given this highly meticulous and detailed description of what's going on!

I'm debating on just starting from scratch. Drain all fuel, wash/rinse fuel tank (I bought this used so have no idea what it looked like in there prior to me buying it). Then work forward, put new filter/seperator on firewall.

Oh, and I cracked two of the three injectors to make sure that fuel was coming out (it was) AND that it was red (diesel) verses clear (water). It was red. Implication being it's getting fuel (and putting out tinted exhaust, not 'black' but dark.....not white/steam (then again, engine isn't really hot enough to create steam yet.

Engine oil is at normal level.

BravoXray · May 13, 2023

Were you low on fuel? If so, you might have gotten a slug of air in the line and caused the rough running. I have had mine pick up some air when I mowed the banks around my house on less than a half tank of fuel.
If not, it might be a good idea to change the fuel filter.
Also, make sure the lift pump is clicking and pumping fuel to the filter.

Richard · May 14, 2023

Full tank of fuel. I'm pretty OCD on keeping all my machinery full so that the 45-50 gallons I have in cans will fill it back up.

There is a quiet sound with key on (electric pump?) When I initially went to remove fuel filter (held on by two "snap on/off' levers.... fuel sprayed out a bit letting me know it was under pressure which I didn't expect.

Owned mower for maybe three years now and though I can't rule out the filter (I intend on replacing it now) I put all new filters on it when I got it so the filter WOULD be around three years old.

Also, testing to see if it was air, I removed the air filter and it did same thing. I suppose it's slightly possible that something is obstructing the air passage.... but the hose from filter to intake is intact and I can wiggle the filter off. That refocused my thoughts on fuel first.

The tinted exhaust suggests it is getting SOMETHING (dribble) in there. This doesn't spray fuel at injectors like my big tractor or backhoe spray when you loosen them so I don't know if the spray that is there is correct for this small engine or if that's my clarification that it's fuel restricted (though I'm leaning on that being the issue)

I don't want to drain it all but this is why I got to thinking it might just make sense to start at the back (tank) and empty/clean my way forward.

BravoXray · May 14, 2023

Sounds like a plan.

Let us know what you find.

Richard · May 15, 2023

Update: Went to Deere dealer this morning. Got a new filter/water separator. he showed me there was also a prefilter inside the tank.

Came home and:

1. Removed chassis to access fuel bung
2. Removed fuel supply from tank
3. Pulled supply line out of fuel tank.... It's MISSING filter on the end so no obstruction there! (tube was also free flowing)
4. put back together, took inlet (to new filter) got catch can ready, turned key on.....fuel came at steady pace.
5. Removed filter/water separator, installed new one
6. Cracked injectors at cylinders, cracked other end coming from fuel pump.

Tried to start it.... just whirled over.... sputtered once, whirled over.

Suddenly, SPRANG to life for .93 seconds, then died.

Tried again, whirled over, sputtered....whirled, whirled. Tried again whirled over, SPRANG to life for .93 seconds and died.

So... here's my logic, am I thinking it through reasonably?

Tank, check
Filter, check
Fuel flow, check

All TO the pump

Engine springs to live every now & then.... so now I know:

1. Getting compression
2. Internals are implicitly working correctly (pistons attached, crank turning, air getting in)

So now I'm narrowing down on actual fuel delivery.

Eyeballing the pump. I don't know yet, which screw to loosen to bleed it. I want to find the service manual before I start loosening potentially high pressure ports so I know which ones they are.

Ultimately, would the pump be a reasonable next item to look at given what's been done thus far?

I would think if I had a bad injector it might run rough, but it would run. Besides, I'd presume it would not spring to life for .93 seconds running/sounding 100% fine for that short duration.

2manyrocks · May 15, 2023

Getting a diesel reprimed can be a repetitive process before you get 100% of the air out.

Richard · May 15, 2023

Went back out, saw the 'starter solenoid' sitting on side of engine. Thinking, Gee, I thought starter was on OTHER side of engine (it is)

Ahhhh, this is the fuel shutoff solenoid!

Would not work with key on/off. Put rope around it, pulled back, mower ROARED to life.

SMOKED like a bandit because of the oil/fuel that was sitting on outside of engine (from me taking things apart) so that smoked off.

So, now I'm getting somewhere!

Decide to move from right in middle of driveway, to out of way. Won't budge.

Some oaf had left High/Low selector in neutral....oops. Got that moved. Then on a lark, clicked the (electronic switch) to start the blades.

I figured I might just put the rope around my waist so I can get out there to cut the high grass before it rains.

NOW, the blades won't work (WHAT?) I wonder if it's the safety switch under seat. It's connected. It's getting power (but now, I still need to check for continuity from the leads to the seat switch)

I turn attention back to fuel solenoid..... put DVM on it. It's also not getting any power. So now I'm thinking it might be an electrical issue. I'll need to trace down the wiring or try to bypass it to confirm suspicions.

Oh, and the engine now, won't even as much as "click". Won't start, won't click yet minutes ago, it was roaring.

Bout time for me to call it a day (clouds rolling in) so this will be on hold until I can trace some issues. All fuses are good AND test for continuity. Lead on fuel solenoid was loose in the crimped on lead so I'll crimp that better.