TZ25DA Losing RPM's ~Help!

[newholland4me]

Ok, first let me say that I am a girl so go easy on me. This tractor was purchased new April '07 (has 90 hrs.) and has been just great right along. It has a Woods finishing mower on it. I took it out to mow the front field which is very low and dry right now so no real load on engine. I mow for approximately 45min. and then RPM's start dropping off rapidly for no apparent reason. I immediately disengage the mower and drop the throttle and engine is shuttering still. I have to turn off engine and wait a few minutes then restart. I will still have mild shuttering but as long as I keep it at around 1000 RPM's and let it just sit it will usually clear up after a while. Takes a few tries at times. The longer I wait to restart, the better my chances are of getting less shuttering and 'clearing'. I may be able to move throttle forward VERY slowly then and I *may* be able to actually get throttle to 3K RPM and mow for a short bit before the RPM's start dropping off again. Engine oil light NEVER comes on and engine remains perfectly cool. I have checked the air filter and oil and they are fine. Hubby did change the oil at 50hrs. and did all of the recommended maintenance. Is this problem due to dirty fuel??? I also tried taking the fuel cap off immediately upon losing RPM's to see if air was needed....no difference. There is no water in the bowl and no obvious debris. If it is dirty fuel, after bleeding the system, it is necessary to replace both primary and secondary filters, right??
This stuff ALWAYS happens when hubby is out of town.
I am chilling the wine. Any and all help is MOST appreciated. I would much rather be riding my horse.

 

[mahlers]

It certainly sounds like a fuel problem. A similar thing happened to me a while back, and it turned out to be a bunch of debris in the fuel tank that was clogging up the fuel inlet. I'm not sure how it got in there because I'm very careful with fuel, and when it happened I only had around 70 hours on the tractor. I drained the tank, blew out all the lines, and everything has been fine since.

 

[newholland4me]

Thank you for your post. Hopefully, we will find out tomorrow if the problem is fuel related. Going to drain all of the fuel, install new filters (have primary & secondary) and replace with new fuel. I sure hope this resolves the problem. I would love to get my front field finished. Do you happen to know of a good additive that will clean and lubricate injectors as well as supplement the low sulphur diesel? Thanks again.

 

[newholland4me]

Mechanic came this morning, bled fuel, replaced both filters, replaced fuel with red diesel. Weather is crumby so no mowing today. Hopefully, I will be able to try tomorrow and HOPEFULLY the problem has been resolved. The mechanic did not see anything significant in the fuel that he drained nor anything in either filter of any significance. So.......???? Guess I will know soon enough.

 

[Soundguy]

Goo dluck with it.

In general.. diesels that starve out and laock power have a fuel issue like you have bene told. Air starvation can do it as well.. but you usually get black smoke when that happens..

I'm not familiar with TZ series.. but ont he larger units, the fuel petcock can become plugged with biologicals and other gunk.. etc..

Soundguy

 

[JC-jetro]

Ok,
This stuff ALWAYS happens when hubby is out of town.
I am chilling the wine. Any and all help is MOST appreciated. I would much rather be riding my horse.

I once had the same issue and it was fuel related. I was scooping up some cow manure and actually got stuck in it I kept going back and forward trying to get out of the muck to no avail.. ended up putting some broken branches below tires just to get some traction. I finally got myself out of sticky situation. I had enough and was heading to the barn and the tractor started shuttering , could not raise the rpm, and ran pretty rough but never died. At the the barn I took the fuel hose off and tried to open the fuel valve and it only trickled . I then pushed a bit of compressed air in to the open valve and actually helped the situation but still not a steady stream. I ended up taking the tank off, dumped the fuel in the container and cleaned the valve port and the tank. Although I had no rust and just a bit of sand in the bottom of the tank what caused the blockage was very small thin shaving of the rubber seal from my tank fuel cap. When I looked the bottom of the cap I notice a bit of loose rubber hanging.. I guess the shaving went in the tank when I tightened the cap and all the back and forth I was doing sloshed the fuel around and caused the rubber shaving block the valve. I made sure my tank was completely clean before I put the old fuel back in the tank using a big funnel and a through couple of clean coffee filters.

Jc,

 

[newholland4me]

Well, I just mowed for a short while (in the snow!)...just big light flakes falling here in Fort Worth. I mowed for about 30 min. and the SAME thing happened again!!! I was making a hard right turn (if that is significant??) and RPM's started dropping off, engine shuttering and I had to shut it off. I wait maybe 3 min., started engine and had to keep it at around 1K RPM for a few min and then slowly increase RPM's to around 2K and took her back under carport and parked. I am so frustrated. This 'stuff' always happens when I am flying solo. Any more suggestions out there??
Oh thought I would add: never any black smoke, but mechanic did say that he read on the NH tech. support something about gas cap not allowing air. So when this has happened, I have loosened the gas cap immediately, but to no avail.

 

[dqdave1]

It is a fuel problem. Remove fuel line before filter and check fuel flow; this will determine if you have a fuel plug in tank. If good flow; remove fuel line at where it enters the injector pump, you should have good flow there. I am assuming it is gravity feed. If you have flow there; I would bleed the injector pump while engine is off, to remove all air. Try it again. You may need to bleed each injector ( high pressure; be very careful) to rid of air but if it runs fine for the indicated time I do not think that is your problem. You may be sucking air into fuel lines at fuel filters; make sure they are tight.

 

[WTA]

I was going to suggest maybe you got some gasoline in the fuel but you already solved that problem. I've had to fix a bunch of them like that that ran exactly as you described. You already had the fuel changed out though.

My gas cap is vented, Yours may be too. Try loosening the cap next time it does it and see what happens. I also have a vent between the two sides of the gas tank and another one going from the top of the tank up into the top of the fender. Mud dobbers are notorious for getting into things like that if the cap falls off the line.

I would recommend pulling the fuel lines like was already suggested too and see if you have a strong flow through all of them. It almost has to be one of the lines or a vent plugged somewhere.

 

[wny770]

Take this for what it's worth.... My little TZ25 was starting to run rough, loose RPM's at times. A friend of mine told me to use power service. Yeah, OK... So I tried it and WOW. All the rough running went away. Now, I make sure and put a very little amount in every new tank. Maybe I had some dirt? water? I don't know, but it made a beliver out of me.