# Hi-Ranger question regarding idle.



## Watchit (Aug 16, 2013)

Just purchased first boom truck 55' Hi-ranger. Lift works great but have my first question. When I engage the pto for the unit the idle bumps up, as I would expect, but then the idle kicks up and down every 15 secs or so. Even if boom is not being moved. Is this normal? It does throttle up when the boom is in use. But why does it throttle up and down when the boom is not being moved? I thought I heard some cavitation when this happens so I'm going to check hydraulic fluid level tomorrow. Thanks for any help. Watchit out there...!


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## old_soul (Aug 19, 2013)

Does it run off the truck engine or a small pony motor?

My hi ranger runs off the diesel truck engine, there is a switch that kicks up the idle when you are ready to use the boom and when you cradle it you idle it back down.

i've never seen one idle up and down, as you descibe


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## treeman911 (Aug 21, 2013)

*hi ranger*

everything is fine


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## Mechanix365 (Aug 21, 2013)

Watchit said:


> Just purchased first boom truck 55' Hi-ranger. Lift works great but have my first question. When I engage the pto for the unit the idle bumps up, as I would expect, but then the idle kicks up and down every 15 secs or so. Even if boom is not being moved. Is this normal? It does throttle up when the boom is in use. But why does it throttle up and down when the boom is not being moved? I thought I heard some cavitation when this happens so I'm going to check hydraulic fluid level tomorrow. Thanks for any help. Watchit out there...!



I worked for international truck and engine for 15 year, specialized in body integration with altec and terex and versalift booms etc. sounds like you have automatic idle with hydraulic flow (a flow switch in the main pto output line). If you're hearing cavitation, perhaps the fluid level is low and not producing enough flow to idle it up? Really could be a lot of things. Older internationals would kick the revs out if you had the 4-ways on. Either way, I'd take it to a shop because it doesn't sound normal to be idling up and down every 15 seconds. Kinda hard to feather the controls like that too....


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## Watchit (Mar 13, 2014)

Mechanix365 said:


> I worked for international truck and engine for 15 year, specialized in body integration with altec and terex and versalift booms etc. sounds like you have automatic idle with hydraulic flow (a flow switch in the main pto output line). If you're hearing cavitation, perhaps the fluid level is low and not producing enough flow to idle it up? Really could be a lot of things. Older internationals would kick the revs out if you had the 4-ways on. Either way, I'd take it to a shop because it doesn't sound normal to be idling up and down every 15 seconds. Kinda hard to feather the controls like that too....


Hey Mechanix365..thanks for your time and info.


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## sgreanbeans (Mar 15, 2014)

Mechanix365 said:


> I worked for international truck and engine for 15 year, specialized in body integration with altec and terex and versalift booms etc. sounds like you have automatic idle with hydraulic flow (a flow switch in the main pto output line). If you're hearing cavitation, perhaps the fluid level is low and not producing enough flow to idle it up? Really could be a lot of things. Older internationals would kick the revs out if you had the 4-ways on. Either way, I'd take it to a shop because it doesn't sound normal to be idling up and down every 15 seconds. Kinda hard to feather the controls like that too....


You need to stick around! Would be great to have a guru on here!


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