149 update

[BIGBEAR]

I have a 149 that I picked up very cheap in the north Ga. I,as well have been putting money in it..$20 here and there..it is still solid and stronger than anything Ive owned..Mine does slow down when warm and going up hills..but I recently cleaned the round cooler in front of the trans..and changed fluid and filter..it does not bog down anymore...I agree it is something I will pass down to the youngins..keep at her..she's worth it..If I can assist in any way let me know!

[papaglide]

Originally Posted by rfrank

As it was explained to me and Ill do my best to explain it so bear with me. Cub hydro should be driven at recommended rpm to keep pump pressure constant there is some so to speak slip or slowing down of the hydro under a load. The engine is spinning a pump which in turn is turning a fluid motor. In our cars the fluid coupling is usually a torque converter. When incurring a load it gets to a point the pressure change causes a downshift to a lower gear driven by fluid in our cars. The cub hydro doesnt have gears to kick down too. The cub has a swash plate that tilts 15 degrees one way and 7 the other way. So for us to get constant speed there comes a point that you have to give it more angle to allow more fluid to be delivered to the hydro motor increasing torque. The springs and cam plate do a good job, but are limited to laws of physics. Other hydros use other means to try and offset the load. The sun hydro is a simple design, effective, maybe not terribly efficient but anytime you transfer energy thru another medium you loose energy. The tractor shouldnt come to a complete stop on most grades, Thats either out of adjustment or the pump is sufficiently worn that it cant apply enough force to turn the hydro motor.

Heres a good example. Spray a stream of water at a fan blade, it turns fairly easy, now spray that same water stream at the same fan with a head wind slowing the fan down(load), what do you do, either you spray the water towards the outside of the fan which applies more torque, or you increase the stream of water. Thats what we have to do with our hydros. Now if the wind picks up you get to a point where no matter how much water you spray it cant overcome the load of the wind. so something has to give, slippage. I hope this helps.

THANKS!! You explained that so well that even a simple dude like myself could understand it!! I do appreciate your explanation!!

[aagitch]

Nice observation. I've always felt that these pumps perform better at max rpm. What's your guys opinion on plowing. I plow at full rpm because I feel the pump will perform better. I also feel it is better for the pump. I also feel it is better for the engine since it is air cooled. But, out of about 10 of us at a plowday this spring, I think I was the only one plowing at full throttle. Once guy was plowing almost at idle, you could hear the pump whining really bad.

[mirt54]

Originally Posted by aagitch

Nice observation. I've always felt that these pumps perform better at max rpm. What's your guys opinion on plowing. I plow at full rpm because I feel the pump will perform better. I also feel it is better for the pump. I also feel it is better for the engine since it is air cooled. But, out of about 10 of us at a plowday this spring, I think I was the only one plowing at full throttle. Once guy was plowing almost at idle, you could hear the pump whining really bad.

FULL throttle, for EVERYTHING!! LOL Marty

[Matt G.]

Originally Posted by aagitch

Nice observation. I've always felt that these pumps perform better at max rpm. What's your guys opinion on plowing. I plow at full rpm because I feel the pump will perform better. I also feel it is better for the pump. I also feel it is better for the engine since it is air cooled. But, out of about 10 of us at a plowday this spring, I think I was the only one plowing at full throttle. Once guy was plowing almost at idle, you could hear the pump whining really bad.

It really amazes me how many people don't realize how much hotter an air-cooled engine runs under load at less than full throttle. It's not good for the hydro either, as much less air will be moving over it at less than full throttle. Since you can infinitely vary the speed of the hydro, it's just stupid plowing at anything less than WOT.

[rfrank]

I learned along time ago how much heat an air cooled engine can generate with my motorcycle. I ride a 600cc air cooled dirt bike and when it gets really hot and Im chugging her hard running 93 octane she will preignite and I can hear the pinging through the cooling fins. No cooling fans there.

[Mike1450]

WOT is the only way a Hydro should be used under load, plowing pulling etc...

Just for the fun of it attached is the principles on how the hydro work.

[rfrank]

axial piston fixed displacement motor, yeah about that. . . . simple, and simple I like:biggrin2.gif:. I always had a hard time with hydraulic theory and my brother has a bachelor in hydraulics, go figure.

[FFGino]

Point #1, wide open throttle is governed to 1750 rpms by design (according to the Kohler engine manual). If you are driving a hydro, you have infinitely variable ground speed available unlike the manual trannys. For proper operation of the tractor, read optimum cooling and power transfer from engine to equipment, always run the engine at full throttle when under load. That is when turning the pto, pushing snow/dirt, or anything that requires the engine to work harder. That is verbatim from the mechanic at my local Cub dealership. Also, the mowers cut better when you control the ground speed with the gearshift/hydro lever instead of the throttle!

Point#2 the above mentioned mechanic told me that the reason a lot of older cubs seem to 'slip' when navigating a hill is because the spring in the damper control has become weak. The cheap fix (as opposed to buying new springs) is to remove the springs and to install either 5/16" or 3/8" lock washers over the t shaped plungers on either end. Upon doing this, my 129 no longer feared the hills and continued to pull without any further need of attention while I was mowing. I tried all the other fixes, clean fluid and filter, clean fins, adjusting the linkage, all to no avail until I installed the lock washers.

[Matt G.]

Originally Posted by FFGino

wide open throttle is governed to 1750 rpms by design (according to the Kohler engine manual).

You might want to double check that...WOT is 3600 rpm on nearly every air-cooled engine I have ever worked on, including Kohler K-series...