MK-17 Hydraulic issues

[bigmellon]

Gents,

I finally have the LVS coupled to the MK-17 RBU. It runs and drives just fine. When parked, sitting at idle, and I pull the hydraulics lever out to provide power to the RBU and the engine strains and stalls. I did this twice with the same result. I even tried giving the engine more throttle to maintain power... But it would seem I have an issue with the hydraulics. Could a line be crossed? The fittings are all a very special size to prevent this. Dead headed? Not that I know all of what I am looking at, but the RBU looks to be in very good shape. New paint, undercoating. Heck, the thing looks to have been overhauled or rarely used.

I am reading through the manuals and have not found anything pertaining to this. Has anyone experienced this issue and have any insight into the next step of trouble shooting? I would sure like to unfold that crane and see how it works!

 

[bigmellon]

I couldn't resist sharing the panoramic shot of the BEAST!!!

 

[73m819]

When the aux. hyds. are engaged, there is supposed to be a auto throttle that engages to prevent this, this little tit- bit of info was culled from the MK48 -10

ALSO the -10 says "MAKE SURE THE AUX. HYDS CONTROL LEVER IS FULLY ENGAGED" if not you will get you this condition, I have been told that due to not being used for a long time, the change over valve may have rust that prevents full engagement.

 

[bigmellon]

So, the change over valve seems to move freely. How much movement should I have on this? I am guessing it moves out about half an inch to change over. Is that adequate?

Also, is there a way to test the auto throttle?

Thanks!!

 

[bigmellon]

Here is the OUT position on my valve... Is that enough throw? Stalls the motor every time I pull it. Also, a light goes on for manual disengage of hydraulics in the cab.

 

[turnerman]

check to make sure there is not a cut off valve on the pressure side from the pump. Mine did the same thing ended up being a cut off with a square nob that i turned with a adjustable wrench and then got flow and everything worked fine. Mine was behind the manual valve handles in towards the middle of the crane structure. trace the line from the pump under the crane and up and you will find it if yours is like mine. Good luck
alex

 

[bigmellon]

I have a Wajax crane on my 17. I was just looking at all of the lines and can not see a shut off valve that you speak of.

 

[BradBMI]

Also check all the quick disconnects. If one in not all the way in the fluid will have no where to go and stall you out