Model Part No. Old Part No. Description
LMAC-1 R431007550 P-090196-00000 Standard Unit
LMAC-2 R431007552 P-090197-00000 Standard unit with shaft brake control signal
LMAC-3 R431009156 P-090198-00000 Unit with proportional reversing interlock timing
LMAC-3C R4310091167 P-090393-00000 Unit with proportional reversing interlock timing for 3600 Series Caterpillar® engine

Weight: 87 lbs. (40kg.)
Maintenance kit for the above units is Part Number R431006453 (P -064517-00000).
Caterpillar® engine is a registered trademark of Caterpillar, Inc., Mossville, IL



LMAC Control Units incorporate the following interlocks and operational features…

GOVERNOR POWER BOOST– applied at the time of clutch engagement to prevent engine stalling and possible engine reversal­ boost is adjustable for magnitude and duration.

CROSS-ENGAGEMENT INTERLOCKS– monitor clutch pressure to insure that one clutch fully vents before the opposite clutch can be inflated, i.e. “ahead” clutch must fully disengage before “astern” clutch can engage.

TIMED REVERSING INTERLOCK CONTROL– provides an adjustable “neutral” hold time during fast reversals to allow engine and propeller speed to decrease to an acceptable level before opposite clutch can be engaged.

CLUTCH PRESSURE/ENGINE SPEED INTERLOCK– insures that selected clutch inflates to lock-up pressure before engine speed can be increased.

SOFT CLUTCH ENGAGEMENT– provides smooth engagement to reduce gear shock and engine loading by two-stage rate of clutch fill. Initial fill is at a controlled rate for soft engagement then opens to maximum flow rate for rapid fill.

SHAFT BRAKE CONTROL (optional)- activates shaft brake in synchronization with clutches. Brake releases when clutch engagement starts and applies when clutches release. With brake control the “timed reversing interlock” provides neutral hold time to permit the propeller to be stopped.

PROPORTIONAL TIMED REVERSING INTERLOCK (optional)- provides an ahead to astern reversing time which is in proportion to vessel speed (adjustable). Since timing is proportional to speed, low speed maneuvers for docking and shifting are performed with minimum interlock timing for faster handling.

Port Numbers
1A – Ahead Clutch Out
1C – Ahead Signal In
3A – Astern Clutch Out 3C – Astern Signal In
SA – Speed Signal Out BC – Speed Signal In
AHD CL – Ahead Interlock
AST CL – Astern Interlock
SH BR – Shaft Brake Signal