Tech Tips: Installing the Z-Lock Manual Jack Plate

October 16, 2014

Welcome to another edition of T-H Marine Tech Tips! This section will feature many of our products and offer advice on installation and maintenance. Today we are going to cover installation of the T-H Marine Z-Lock Manual Jack Plate.

We recommend a full service marine dealer install this product to insure proper fit and trouble free operation. We cannot assume any liability for improper drilling of transoms or damage due to improper installation.

The T-H Marine Z-Lock Manual Jack Plate is designed to fit all V-4 and V-6 outboard engines. Do not use this product with a V-8 engine. These jacking plates will accommodate those motors equipped with dual steering and up to 90 degrees of tilt angle. The plates are pre-drilled to accept the mounting bolt pattern of most outboards. Mercury models manufactured from 1976 to 1979 will require special installation steps. Please see a marine dealer to help in the case of these older engines.

The jacking plates are pre-drilled to fit the existing mounting hole pattern in the transom. The short side of the jack plate mounts against the transom. Mount with ½” diameter stainless steel hardware and lock nuts with over-sized washers inside the transom. Apply protective sealant around bolts and holes on both sides of the transom to prevent leaks. Mount engine to long side of jack plate also using ½” diameter stainless steel hardware with lock nuts and washers.

IMPORTANT: After engine is in place, tighten all hardware securely.

To adjust the height of the jacking plate, loosen the three side locking bolts on each side (6 total). Turn the adjustment bolt in the top center of the jack plate clockwise to raise the jack plate to the desired height. We recommend the use of a box end wrench, open end wrench or a socket. DO NOT USE AIR TOOLS! After adjustment tighten all side locking bolts securely. (We recommend 80 ft/lbs).

CAUTION: DO NOT loosen or adjust the four locked bolts on the center adjustment screw. These move together and only serve to adjust the height and do not require adjustment.


Does the wider side of the jack plate mount to the boat or motor? 


The taller side will be mounted to the outboard with the shorter side mounted to the transom.

WARNING: It is the Owner’s responsibility to maintain tightness of all bolts and nuts to a minimum of 80 ft/lbs of torque.

Maintenance: Insure all side bolts are tightened to a minimum of 80 ft/lbs or torque. This should be done after 3 hours of initial use and after every 10 hours of engine use after that. This check should also be done after each 300 miles of trailering. A visual and manual inspection of all side bolts should be done before each engine use to assure that all side bolts are in place and are not loose. Do not use engine if any bolts are loose or missing.

Limited Warranty: T-H Marine warrants to the first retail purchaser of this product for a period of one (1) year, from the date of original purchase, that this product will be free from defects in material and workmanship. This applies only to the original purchaser and must be returned to the manufacturer prepaid and with the original invoice. This warranty shall not apply to any product that has been repaired, altered, abused or installed in an improper manner. In no event shall T-H Marine be liable for any incidental or consequential damages. This warranty applies only to the replacement or repair of this product and not to any replacement labor charges. Warranty is void if used for (1) Commercial boats, (2) Competition boats, (3) Improper installation, (4) Engine horsepower exceeding USCG maximum rating for the boat.