I think my 1572 is jealous of the new 1772
 

So, I got my new 1772 about 3 weeks ago. It is running well and I am just getting to the point of getting ready to mow with it. I think my 1572 is getting jealous and starting to throw fits. My wife said after I was done mowing that it behaved the same way for her the week before but she forgot to tell me about it and with this episode she said she sees a pattern developing.
I have a decent sized yard to mow, a little over 2 acres. Well the 1572 runs fine for the first hour and a half or so, then I swear the engine slows down a bit, first unnoticeable then more drastically. After it starts behaving this way, the fits happen more often in frequency. Basically, the engine slows right down as if it has no fuel, if I stop the forward motion with the tractor, sometimes it gradually recovers engine speed, sometimes is does not and the engine stalls. Sometimes after stopping going forward, and trying to recover I will disengage the deck. Sometimes this is enough, on several occasions the engine starts belching heavy black smoke while recovering and I can smell raw diesel with the exhaust.

The strainer in the tank, and all the filters were replaced within the last 2 months. Since I had the problem with the algae with one of my diesels, they all drink form the same tank that has been treated with biocide. What does this sound like to you. I am looking for any and all suggestions. Could it be the injection pump on the way out? If so, what are typical symptoms of a bad injector pump?

Generally black smoke from a diesel is caused by, lack of air, too much fuel or lugging.

On the 2- 3 times when it was sitting there, running at 1/4 to 1/2 speed, the hydro was set to neutral so there was no forward or backward and the deck was off. I remember 1 time in particular as it was happenning , being puzzled wondering where do yuo start to diagnose this. The engine when being restarted, spins over normally and does not turn over slow as if something is binding. It's either too much fuel or like you said Sam, not enough air.

When was the last time you checked the air cleaner and the screen?

Every spring before I start for the season, it get a new air cleaner whether it needs one or not and everything is all cleaned out. My wife said it start out running fine but after an hour to an hour and a half, the trouble starts. If I wasn't getting fuel, I could explain the loss of power and slower engine speeds, but when it starts belching out black smoke, there's too much fuel to burn. I'm going to have to see if I can find a Kubota D600 Engine workshop manual for reference. If I remember correctly there was a troubleshooting section in it. However it was like using the shotgun approach in that you will eventually find the problem byt replacing lots of parts.

Link for the Bota service manual.

http://www.onlycubcadets.net/forum/s...ead.php?t=4660

Thanks Sam. I'm going to double check the filters out just to rule them out as well as for a malfunctioning low pressure fuel pump.

Black smoke as a general rule is just as Sam said. HOWEVER, it can also be caused by timing, and low injection pressure.

Since you seem to have all your bases covered, the filters are relatively new and you have cleaned the fuel system, there are a couple places to start.

Here's where I'd start:
*Check to make sure you don't have a fuel line collapsing internally.
*Make sure the charge pump is working.
If those are fine;
*Check the return line. Make sure it's good.

If you still can't find any problems, start taking the fittings out of the injection pump. Take the inlet out first (see pic). Make sure the small hole in the "bolt" isn't plugged. While it's off, turn the key on and let some fuel bleed out of the line to flush it.

Attachment 55817


After that, pull the return fitting. (See pic) As you can see, it has a very small hole in it. With the inlet line all reassembled, and hooked up, return fitting out, again cycle the key and flush fuel through the pump. This will flush out the inside of the pump. With the problems you have had with bio-fuel, you may have junk in the pump itself.

Attachment 55818


Report back if all that doesn't fix it and we'll go from there. You should never "shot-gun" any repair. I have never seen a book that said to replace parts without telling you how to test them first. There is a test and a procedure for everything. Diesel motors are too expensive to just start replacing parts. I highly doubt you have a failing injection pump. The pump is a mechanical pump, and if it was broke, it would be broke. It wouldn't work for an hour and then suddenly quilt. It just wouldn't work at all. Keep us updated. :beerchug:

Thanks Jonathan. I'll start digging into it and see what I can find. All of those fittings you show were last touched when assembled at the factory. What really puzzles me is that if only happens after it gets hot or after about 1 1/2 hours of running......

I've seen stranger things. I'm betting either the electric pump is getting hot and not working, or a return line is plugging. Might check the fuel cap too. May not be venting......

For the record, and better explanation:
The reason why fuel starvation (like a weak electric pump) causes it to smoke is because the plungers in the injection pump can't "suck" fuel. If they aren't being filled with charge pressure, they can't or won't fill all the way. When this happens, they don't inject fuel at the correct time, or the proper amount. That's what makes it smoke. I'm not 100% sure this is what's going on with your machine, but it fit's the bill.

If I place a "t" in the fuel line after the electric pump, what should I expect to see for pressure if I connect a gauge when it is running correctly vs. when it seems to be starving for fuel a couple of pounds if good??

Jonathan, you may be onto something. Whenn it was misbehaving last, I put my hand on the pump to feel if it was running, since I could not hear if it was running with the engine stumbling. The pump was very hot to the touch, almost enough to burn you. It was hotter than a cup of coffee.

The tank cap is brand new and was replaced right after I changed all the filters.

If that pusher pump is getting that hot, I'd say it's bad. They get warm, but not HOT. Most of those pumps make between 5-10 PSI.

You can get those little electric pusher pumps at O'Reilly's. There is one just for diesel fuel. Part number 12D, line code MRG.

How'd this turn out? Did you get it fixed? :bigthink:

Jonathan, I did not finish digging into this yet. This past weekend I was busy putting together all the painted parts the PO had for the 60" deck and mount for my new to me 1772. After I got it all together it was either get some seat time on the new 1772 and mow the lawn or trouble shoot the 1572. The 1772 won the coin toss. It had a little trouble getting the deck started the first time as I think everything was stiff.

I will get some pictures in another post of the 1772 re-united with the deck and get additional info in for the 1572. I did pick up some fuel line and a "T" to splice in with a gauge to see if the fuel pressure is dropping when it starts acting up.

I finally had a chance today to work on the 1572. I started my mowing with it until the engine started to die. I left it running without the deck engaged and went in the garage to get the parts I needed to put a "T" in the fuel line after the pump to get a gauge in it. I went back out to the 1572 with all my stuff, shut off the engine, and disconnected the fuel line after the electric fuel pump. The line was, for the most part, dry. So rather than put a gauge in with the "T" I just got an old coffee can, held it up to the pump output and turn the key on. There was no flow, only an occasional drip in the can. AHA! I thought to myself, a bad fuel pump. So I ran to my part stash and grabbed one I had and installed it. I turned the key back on and still nothing came out until I realized the pump wasn't primed, so I put mu finger lightly over the output so the air in the pump couldl be purged and viola, I had a stream of fuel coming out of the pump. I buttoned it all back together and prepared to do the other 1/2 of the mowing. I got about 1/2 way through the remainder, and it started surging again. I shut it down and pulled the hose off of the pump output. It was dry in the manner than no fuel dribbled out when I disconnected it. I got my coffee can out, turned the key on and nothing. I help my finger over the pump output slightly, then there was fuel. I put it back together and finished the lawn.

OK I am at a loss. I am pretty sure the problem is no fuel, BUT with the fuel pump, ALL filters, fuel lines and the fuel shut-off valve replaced ... what is left ? I need some ideas on what to try next. I cleaned the tank out with "Super Clean" when I replaced the fuel lines along with the fuel filters and replaced the fuel cap on the tank. I also loosened the cap to make sure there was no vacuum building up in the tank. There can't be much left.....

was the pump in your parts stash new

I had some brown hairy crap in the fuel tank of my 1512. Would run for some time and then die. If I let it set would start back up. I had to remove the gas tank and clean it completely out. I filtered the fuel as I removed it from the tank and was surprised how much junk was floating around.

That's what I want to know..... :bigthink:

When you test with used parts, you can't assume that they too are not the problem. But being that they are both doing the same thing...... that is interesting. Now you know it isn't getting fuel. Why not check to see if the pump is losing power? Maybe it's only getting 6V instead of 12....... :bigeyes:

The pump was a new pump and on the tank, this past spring I had drained the tank, pulled it, washed it out and put in a fresh tank of fuel.

Check the voltage running to the pump when it quits.

Also, you may try pulling the line feeding the pump and see if fuel comes out. Just to be sure..... It's a quick test, and you should only need to do it once.

Oh..... was the pump from CC? Or some kind of aftermarket? How old was it. Hadn't been on your shelf for years or something had it? They are just a rubber diaphragm pump. They can go bad sitting.

Jonathan, the pump was an actual CC pump, new in the box but was on the shelf about 2 years. Still had the rubber caps on the input and output.

This still has me puzzled as how this could be running perfectly fine for over an hour with the new pump, starts acting up, I check the pump output and it appears to be dry, then once pumping runs for another hour and finishes the job.

:bigthink:

Frank, what happens if you pull the inlet to the pump off and hold it below the tank? I'm thinking the screen or something else in the tank is causing your problem.:bigthink:

I agree with Todd. Check the flow from the tank. I've seen fuel filters from the larger diesels, 1466, etc., plumb full of junk or algae. The gas/fuel today just isn't what it used to be.

Todd and Josh, I think that is an excellent next step. Unfortunately during the week, it's usually dark by the time I get home from work. I plan on looking at this more on Saturday. I want to disconnect the fuel line below the tank and see if fuel runs out at an acceptable rate. That will tell me what the next step is. If I get a good rate, then it may be another bad fuel pump. I really hate working on the 1572 trying to get to the fuel shut-off, having both the 3-pt hitch and read PTO. The fuel shut-off is buried behind all the covers and shields.

I'd plan on pulling the tank, cleaning it out, replacing the grommet for the fuel shut off and cleaning or replacing the shutoff valve. My bet is your going to find something in the tank that is blocking the flow.

Sam, you're probably right. Fortunately I have some grommets and valves on hand from when I did the same thing to my 782D while replacing the old dried out fuel lines. It may be the time to replace the fuel lines on the 1572 as well.

I did what I mentioned on my 1782 shortly after I bought it. I was surprised at how much crap was in the tank. The Cyclops have 2 fuel shutoff's and one was packed full of dirt the other just barely flowed any fuel. You having only 1 shut off may be even more challenged.

I'd tee in a vacuum gauge to the inlet of the lift pump. That will tell you if you have a restriction or it is just sucking air (leak before the pump). The pump is cooled by the fuel, that is why it is getting hot.

Thanks to all, I finally had time this past weekend to look at the 1572. I ended up pulling the 3PT cover off , then disconnecting the fuel line at the shut off. As I took the line off, I had more fuel dribbling out of the free end of the hose than I got out of the shut off valve. It was barely even allowing anything out. I pulled the tank, washed it out, then rather than clean the screen on the shutoff valve, I just put a now one in. I ran it as before and no dying or surging with the motor for lack of fuel. Thank you everyone!!!

Glad you got it back and running. I had to change both filters on my 1782 today. It would run ok but then just shut off. Did that a couple times, decided it was time for new filters. Local Bota dealer had them in stock along with the O-Rings for the secondary filter. So far all good but I need to run it under load to be sure all is good. I'll let you guys know if it has a problem.