Splitter got slow?!?

[HadleyPA]

I know this has been discussed in the past but most are really old threads so I figured I would bring it up again. Last I used splitter was around Thanksgiving and everything was fine. Fired it up Tuesday night and it was so slow it was unbelievable. Homemade splitter with 6 horse HF motor, 4” cylinder and two stage pump. I don’t know off hand what the pump is, but I believe the tag says Northern if I remember correctly. It was acting like it was stuck in the slow stage even with no load. I thought maybe it was just cold and sluggish from sitting for so long so I ran it for about 20 minutes then the wife walked down and even she said why is it going so slow? After that I quit and yesterday after work got a new hydraulic filter and changed it. That seemed to help and now it is a bit faster and is running both stages meaning that when it makes contact with the wood it is slowing down while splitting, however, when I say slowing down I mean unbelievably slow! I then did a time and it was 48 second cycle time when unloaded! Did a couple more pieces and tried again and this time it was 47 seconds. The motor is not working hard at all, in fact it will idle the cylinder in and out and is not much slower than when I timed it at about half throttle. ( I never run it past half throttle, no need!) It does not even begin to work the motor when it contacts the wood and goes to second stage. I don’t have any pictures of the setup but can take some if anyone would like to see it. Anybody have any suggestions as to where I should start? Thanks in advance!

 

[Shagbark]

Sounds like lack of fluid flow or part of the fluid returning to the tank. Check the hydraulic fluid level first. Is there a screen in the suction line, is the line restricted in any way? Check those next. Is the pump making any unusual noise? The valve may need rebuilt due to internal corrosion or the cylinder has blowby and needs seals.

 

[jags]

Couple of things to check...
As said above - fluid level.
Flow - is the pump staying in the low volume/high pressure side?
Restriction - is the line feeding the pump collapsing?
Bypass - is the pressure relief or cylinder seals bypassing fluid (this should be very noticeable with lack of pressure).
Lovejoy connector - is engine rotation being fully transmitted to the pump? A loose lovejoy can happen.

 

[HadleyPA]

Thanks for all the recommendations. I was thinking about taking off the feed line tonight and making sure it was good. But I also thought of something else that may help with the diagnosis. Ever since I've owned it I always had to make sure it would stay in the return mode (basically if you just flipped the lever back it would not auto retract so you had to be real gentle and then it would stay there) I did when I was using it Tuesday night and last night that I had no problem keeping it in the return mode. In fact I could almost just flip it to the return side and it would stay there unlike before. What do ya think?

 

[jags]

That would fall under the "bypass" suggestion above. The valve not only directs the fluid in one direction or the other (or pass through), but in most all splitters it is the location of the relief valve, as well. Funky valves can cause weird results.

 

[Wood Doctor]

OP said, "It was acting like it was stuck in the slow stage even with no load."
-----------------------------
That's entirely possible. Check that by trying to split some good tough crotch wood, spiral grain wood, or green elm and see if it goes right through it at the same speed. If it hardly slows down I would believe that the pump is not shifting out of the second stage and is locked in at full power. If operating correctly, you should also notice a speed up on the return stroke as it shifts back to no-load speed.

My experience with the Lovejoy connectors has been that if they fail, you lose all power because either the key strips out or the teeth (prongs) give up or no longer mesh. You will usually hear a heckuva noise in either case. It is worth checking, however.

 

[triptester]

Although this may not be the cause of your problem pump gpm is directly related to engine rpms. Your pump is most likely rated at 11 gpm at 3600 rpms. At half throttle, 1800 rpms,the pump will only produce 5.5 gpm in high flow. When into high pressure mode at half throttle the pumps is produce only about 1.75 gpm.
In the retail trade use the term gallons per minute while in the commercial trades and hydraulic industry the term is cubic inches per revolution to indicate flow.

 

[aokpops]

pump ! Check other stuff first kink in the line . About always been the pump

 

[ppkgmsy]

If it's not staying in auto-return, the problem could also be the pin, or whatever hardware is supposed to hole the level back.

 

[HadleyPA]

Got it fixed. Was pump. When I took off feed line I found inside it a chewed Half moon key-way and what looks to be part of a tooth from the pump. Sure am glad I took the line all the way off instead of just putting it on the new pump! All is good again. Went from 48 seconds cycle time to 16! Thanks for all the help.

 

[Wood Doctor]

By "feed line", I assume you mean the low-pressure side. I may have a similar problem with mine. Any foreign object that blocks the intake flow can slow it to a crawl. Glad to see that your back in action. Two thumbs up!