Mowing Ideal RPM to operate YM2000, Yanmar while mowing?

[grbillingsley]

Are there any Yanmar YM2000 owners that can tell me what the ideal RPM to operate the tractor at while pulling a finish mower? I mow in high-range 2nd gear, in the 540 RPM PTO, gear 1. Have replace two broken crankshafts. I usually run the little two-cyliner at about 2000 or 2100 RPM while working it with the mower.

 

[284 International]

Run it in 1st gear on the PTO a little under the (red, probably) tick mark on the tachometer (around 2200rpm). That is around 540 PTO rpm. The information I have seen is 588 PTO rpm in first, 730 PTO rpm in second, and 1260 PTO rpm in third all at 2200 engine RPM.

I have no idea how you have broken two crankshafts. It sounds like you're doing what you're supposed to be. If it has happened it has happened, but there's something else really wrong here.

 

[grbillingsley]

Thank you for your reply, and information. With the tractor, I received no information or advice and I don't have any kind of manual for my tractor. I Think it is a late 70s or early 80s model, not even sure about that, rated at 24 HP. I have been mowing at about 2000 RPM. The mower is a 60" Caroni, finish mower. I have never used the tractor for anything but to mow my 3 acres. It always seems to make a quite lot of noise from the motor, I have been told that is because it is a two-cylinder. I mowed today at about 2200 RPM. I am going to try your suggestion and hopefully not break another crankshaft. They are expensive. If you have any other suggestions, I am all ears. Again, thanks. I was hoping someone could tell me the ideal RPM to work the tractor under a load. Greg B.

 

[284 International]

The 2 cylinder Yanmars are notoriously "clanky," in fact, there's currently a conversation going on in the Yanmar forum on that very subject. They are also notoriously durable and long-lived engines.

The ground speed you have described seems about right, too, and a 5 foot finish mower should be handled acceptably by your tractor as long as you aren't trying to cut thick bushes and so forth.

Have you been the one who has done the crankshaft swap both times? Did you get the crank welded, or was it replaced with a new one? (I know you said they're expensive, just wanted to clarify.) If it was a repair place, what did they say about it, or do to check for other things being out of specification?

I'm suspicious that something else is amiss in your motor. These will overheat when not taken care of and abused, or may break rings/pistons when dosed with ether, but to break two crankshafts in that type of application is really unreasonable, and indicates other problems.

 

[larhan31031]

I always run mine in 1st pto@1200-1500rpms in 2H using my 5' Tecma FM150 finish mower(Caroni clone),and it does a great job even through thick grass/weeds.I have never ran my ym2000 any higher than that even with a 5'-16 disc weighted harrow,or 5 1/2' heavy box blade.Mine has about 2000 hrs on it and has never had a problem other than a burnt out headlight.Even at 1500rpms it takes a lot to stall it,usually it breaks traction or burns the mowers belt first...