4500Z engine RPM at fast idle is lower than spec,

prs · May 28, 2015

According to the on dash tachometer the Kubota gas engine is about 250 RPMs below spec. Engine manual says to get that corrected, but the machine seems to be running fine. Then again, some of my work should be done at wide open throttle due to weight of implement and slope and thickness of turf. Just wondering if maybe the specification has changed? Don't want to limit the flow to the hy motors.

prs

BKBrown · May 30, 2015

I know that my neighbor has the 4500 with the Kawasaki gas engine - Ventrac replaced his electronics controller at no cost. Is there a recall on your electronics ?
The neighbor got his 4500 after he turned over his New Holland SCUT and his wife insisted that he get one like my Ventrac that is stable and won't turn over. The neighbor was not injured, but it scared him and his wife.

murphy1244 · May 30, 2015

BKBrown said:
I know that my neighbor has the 4500 with the Kawasaki gas engine - Ventrac replaced his electronics controller at no cost. Is there a recall on your electronics ?
The neighbor got his 4500 after he turned over his New Holland SCUT and his wife insisted that he get one like my Ventrac that is stable and won't turn over. The neighbor was not injured, but it scared him and his wife.

I had my controller replaced this year on a 4500y. Don't know why it was replaced...

prs · May 30, 2015

I am unaware of any recall campaign. The Z is the Kubota spark motor.

I have had a roll over too, maybe 18 years ago. No ROPS and no seat belt. I had the presence of mind to pull the throttle closed and as soon as I hit the ground the steering wheel was in my chest then the belly mower across my right leg. The compact UT rolled clear over and landed on its tires, engine off. Three cracked ribs and a greenstick fracture of lower leg. I am reminded of my close call whenever the weather changes. But, like fallen off a horse when you are a kid, dust off your britches and climb back on. I've been over that same ground on that same tractor several times each year ever year since, except this year. Now the Ventrac treks it and the other steep areas.

prs

Ventrac4500Z · May 31, 2015

If your engine seems to be running at a slightly lower top in speed the first thing you should do is check the engine speed with a photo tachometer.
If you do not have one I'm sure somebody near you or a garage will have one. Place a tape mark on the flywheel and turn the engine up to full throttle. You can also make a mark on the fan belt and do the same if the photo tach reads 3650 you may have an issue with the instrument cluster. Also, sometimes the cable for the throttle may slip slightly in the mount at the engine. To rectify this, simply loosen it up with a screwdriver and a 9 millimeter wrench, slide the cable back in and tighten. You may have to reposition the throttle arm but it is not that complicated of a process. My tractor runs better around 3400 RPM's than it does at 3650, but it's all in how they're tuned. I have set my timing with a calibrated degree timing light. Even though it was close, being with my background I am very picky about how I set my timing.

That being said somebody else in this thread addressed the fact as to why the computer or properly known as the TCC was changed. There were some issues with in the computer regarding cold starts and a few safety items that we wanted to update so we did this and we updated it across the board. It is a revision H but remember the computer does nothing but control safeties in the tractor and not anything to do with the engine

The Kawasaki 4500 P has the engine control unit but it is strictly a pre-programmed digital output to control injection rates based on engine speed and load. The 4500 Z is a direct carbureted engine 3 cylinders in line.

It is going to pull much better than any v-engine that there is.

if you have any further questions please address them to me accordingly thank you have a great day

prs · May 31, 2015

Ventrac4500Z;

Great information. Somewhere I have (or had) a hand held test tachometer for spark engines that has a 3 cylinder setting for the old Mercury 3 cylinder outboard motors. That might work here to, although it may read 2x if this is a lost spark engine design. BUT, the engine runs so well (one exception) that I am not going to fret over it. That one exception? This little puppy LOVES gasoline! I guess a big part of that is that I am spoiled by the efficiency of my other tractor with its Yanmar diesel of 1982 pre-EPA meddling design.

I will check the throttle assembly for any sign of slippage and report back, but I probably will not change it. It ain't broke and I don't want to fix it so that nobody can fix it. ;-)

prs

prs · May 31, 2015

My old induction tach is not to be found, have not seen it for many years and I think it may have been borrowed back then. I did a little online shopping and have a non contact photo tach on the way. Maybe it tell me how fast my head is spinning.

prs

Raw Dodge · May 31, 2015

If your happy with your performance and ground speed,I would leave it alone...you'll save a lot of fuel running at 3400 vs 3650...I have the older briggs 3LC,and I turned it down to 3400, it's much happier there,and it's a torque monster,so lots of rpms arent really needed.id think the kubota inline 3 would be the same.

prs · May 31, 2015

Raw Dodge said:
If your happy with your performance and ground speed,I would leave it alone...you'll save a lot of fuel running at 3400 vs 3650...I have the older briggs 3LC,and I turned it down to 3400, it's much happier there,and it's a torque monster,so lots of rpms arent really needed.id think the kubota inline 3 would be the same.

Great minds think alike. But, the tachometer tool will be a neat addition to my collection and will verify or refute that there really is or is not a short fall. I was also thinking that the torque band of the engine has probably peaked well before its present top end.

prs

prs · Jun 3, 2015

Drum roll please................................

The actual RPM as read by a digital laser photo tachometer is...................... 3,690. So, I am not a little slow, I am a little fast. Big deal. The dash mounted tack is a little off. How do I know the digital smidgital thingy is right? I checked it against an electric motor whose RPM at no load is set by the public power line of 60 cps, it was right on. Neat little tool, wonder if I will ever "need" it again ;-)

prs