Helping out a friend who has a LISTER SR2 in his boat. The AHEAD function of the gearbox works well,but reverse will not engage until a lot of throttle is applied.

Magix Photos Sur Cd . Have down loaded adjustment instructions,looks like the brakeband may need adjusting? Nipping up the brakeband is simple enough so will try it and see if the problem disappears.

May 11, 2017. Lister Lh 150 Gearbox Manual Transmission. Benford Terex Parts. WHITEBenford Terex 1. 5 SINGLE GROOVEBenford Terex 1. DUST COVERBenford Terex 1. C BELT GUARDBenford Terex 1. WASHERBenford Terex 1. CENTRE BODYBenford Terex 1. Lister Lh 150 Gearbox Manual Transmission. OEM Equipment Parts - Ahern Equipment Rentals, Inc. Automotive, Commercial and Marine Instrument and Control System Specialists since 1971. Home; Links; Ordering; Events. Site Map; Terms and Conditions; 1 ton. 2 wheeled trailer.User handbook.

Question is,is the hydraulic system on these gearboxes bullet-proof,is it best to check that side of it out as well? I have rebuilt dozens of marine reversing gear units,but never a lister version. Have you checked the dipstick in the reversing box. Being short of oil would produce the symptoms you describe Spent some time on this gearbox today.

Brake band adjustment is correct,nipped down and 3 full turns back. Ahead adjustment correct. Drained the oil and refilled with EP 80/90. The reverse function engages sweetly sometimes,on some occassions it fails to engage without lots of revs and a few seconds delay. A kind and knowledgable chap who repairs and restores listers suggested altering the hydraulic pressure by shim adjustment.

Looks like the problem may be more complex than it first appeared to be. Any one have any more tips? Spent some time on this gearbox today. Brake band adjustment is correct,nipped down and 3 full turns back. Ahead adjustment correct. Drained the oil and refilled with EP 80/90.

The reverse function engages sweetly sometimes,on some occassions it fails to engage without lots of revs and a few seconds delay. A kind and knowledgable chap who repairs and restores listers suggested altering the hydraulic pressure by shim adjustment. Looks like the problem may be more complex than it first appeared to be. Any one have any more tips? The hydraulic pressure is adjusted by adding or deducting shims from behind the relief valve spring which is situated behind the forward and reverse lever unit on the port side of the box. Adjustments to this should be done with a pressure gauge screwed into the plug port on the boxes top plate,but for the small increase in pressure that you need just a calculated guess would surfice.Probably a weak relief valve spring,but add shims to increase pressure.There are O ring seals on the F&R lever unit behind which the relief valve,spring and shims are so go gently. The hydraulic pressure is adjusted by adding or deducting shims from behind the relief valve spring which is situated behind the forward and reverse lever unit on the port side of the box.

Adjustments to this should be done with a pressure gauge screwed into the plug port on the boxes top plate,but for the small increase in pressure that you need just a calculated guess would surfice.Probably a weak relief valve spring,but add shims to increase pressure.There are O ring seals on the F&R lever unit behind which the relief valve,spring and shims are so go gently. Many thanks bizzard the suggestion i got was that the shims had possibly been increased already to increase the pressure for the ahead gear to release. The astern function is actuated by the 'blow-by' from the pressure control valve,if there is insufficient flow as a result of the release valve being set to high,astern wont engage? If the pressure is set too low,the ahead will be unable to disengage? So,could it be that the pressure is too high? Many thanks bizzard the suggestion i got was that the shims had possibly been increased already to increase the pressure for the ahead gear to release. The astern function is actuated by the 'blow-by' from the pressure control valve,if there is insufficient flow as a result of the release valve being set to high,astern wont engage?

If the pressure is set too low,the ahead will be unable to disengage? So,could it be that the pressure is too high? I doubt that unless the pressure is seriously too high. Hydraulic pressure is only used to obtain neutral and reverse.

There is no pressure required to obtain forward gear. 'The get yer home feature if the hydraulic pressure fails'.The hydraulic servo cylinder which disengages the forward clutch cone is located on the back of the box,near the prop drive flange or reduction box and is held in the gearbox body by i think 3 bolts.Once the piston in this has pushed out and disengaged forward gear when neutral is selected it remains under pressure holding the forward clutch cone out of contact with its mate while in neutral and also while reverse is selected and used.The pressure is only released when forward gear is selected. I have the pressure settings in PSI somewhere if you need them.

They are pretty high in the region of 250PSI for neutral to 300 odd PSI region for reverse. PS You probably knoe all this but.--- The extra reverse pressure is for engaging the reverse brake band. All this hydraulic control is obtained at the selector relief valve barrel which has holes that correspond with oil pressure holes in the boxes body which it covers and uncovers as the operating lever rotates to select the three positions. Edited April 13, 2012 by bizzard.