Viking hydro response

Discussion in 'eXmark' started by Roger, Jul 26, 2004.

  1. Roger

    Roger LawnSite Fanatic
    Messages: 5,940

    I have an Exmark Viking, 36" with 15hp Kohler, pistol grips. It is in the eighth season, probably mowed well over 5,000 lawns, maybe close to 6,000. I repowered with a new Kohler at about 3,500 hours, and this engine has at least 2,000 hours. Most lawns are 25K sq ft to mow, some are as big as 2 acres. So, the machine has been used heavily. Other than the engine and deck spindles, everything else is original gear.

    This season, I've noticed that the left ground drive handle does not return to a "drive" position as quickly as it used to, nor as quickly as the right handle. This happens when making a zero-turn, typically a Y-turn (I often use a Bull Rider in trailer mode). After making the turn (reversing the left wheel) and wanting to resume the next pass, I notice the speed doesn't ramp up as quickly as it formerly did. It may take 2-3 seconds to reach full speed, rather than instantly restarting. I think it happens when the hydro system is at operating temperature, but that is hard to tell. I often don't start making these kinds of turns until the machine has been running for a couple of minutes.

    When the machine is at rest, the response is fine. Moving the speed control lever back and forth, the pump control moves freely. I grease the one fitting on the side of the machine every other day, and nothing seems to be binding.

    My major concern is not the small inconvience of right and left working a bit differently, but IF this is an indicator of a hydro pump going bad. I've never done any work on the pump or wheel motors. The fluid is always topped off to the baffle in the supply resevrior. I change it at the end of every season, along with the filter. I have only used 15W-50 Mobil 1 synthetic oil.

    I know my machine has given me great service, and I know that some of the linkages on the ground controls are pretty loose. They can be replaced. The major components that are vulnerable to failure because of extended use are the pumps and wheel motors. Each are about $300 to replace, and I don't want to make a change. But, the response changes I've noticed since the beginning of the season (now covered about 600 lawns - I work solo) are an indicator of an iminent problem, I would like to know.

    Any thoughts?

  2. eXmark

    eXmark Manufacturer / Sponsor
    Messages: 4,258


    The first thing I would do is just what you've done, grease the outer pivot bearings. When you do this make sure you see clean grease coming from the bearing. If not that may be your problem. The next thing I would do is look at the linkages to make sure nothing is binding up there. It's also a good idea to make sure the pump is lined up squarely with the pivot just in case the mounting hardware has worked loose over time. I would then take the unit to the dealer.

    It really sounds like there is a realatively minor problem in the pump but we would want the dealer to look at the linkages and the pivot bearing as well. Typically when we see older high hour units with these same symptoms (works fine when parked but acts up when under load or moving) the problem is worn cradle bearings in the pump itself. They not expensive but the pump will need to be disassembled and having the dealer do it makes a lot of sense. With replacement pumps costing $300 I wouldn't want to risk improper installation by trying to repair it myself.



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