A To-Do list before removing a MR-1 engine

[WREKS]

"Under edit"


Before removing an engine, there are dozens of things to do. The preparation involved, should not be under rated.

This post traces a procedure I use to prepare to remove the MR-1 engines. I have used it six times between March 2019 and April 2020 (The port engine had water in the oil. The starboard engine was overheating).

There may be some omissions and lack of clarity here, but I hope it will be helpful for anyone seeking information on the preparation work involved. Please, give comments and suggestions!

I depend heavily on the service manual but change some of the procedures when I am convinced that the same results can be achieved. One such procedure is the ECM. I leave the ECM in place and disconnect the cables attached to it. I find that to be easier than removing it.

Here it is:

Before starting:
· run engine for 60-80 seconds without cooling water;
· disconnect battery;
· pump as much oil as possible out of oil tank.

Before pulling engine:

Check Coupler clearance: this will help determine whether additional shims are necessary when reinstalling the engine.
A coupler out of clearance can lead to damage in reduction gearbox as well as intermediate bearings.

Remove the Airbox and Throttle Bodies as one unit:

On port side disconnect or remove:​

Cable Tie attached to oil cooler holding bundled cables that plug in at bottom of airbox;​

Wire Plug at bottom of airbox;​

Cam Position Sensor cable from connector and bracket;​

Exhaust Thermoswitch cable from connector and bracket;​

Throttle Cable (requires removing Airbox Cover and Ribbon Sub Assemblies);​

At front disconnect or remove:

engine temperature sensor from connector and bracket;​

engine thermoswitch from connector and bracket;

pickup coil from connector and bracket;​

lighting coil from connector;​

fuel hose connector;​

​

​

At rear disconnect or remove:
· coupling cover.**Check coupler clearance** Very important to prepare for shimming, if necessary;
· red +battery cable at ECM and slide it from cable tie (it will go with the engine);
· engine bonding cable;
· ventilation hoses, if they are in the way;
· it is not necessary to remove more oil at rear drain plug.

On starboard side disconnect or remove:
· spark plug wires at coils;
· negative ground at starter and slide out of cable tie;
· thermostat housing;
· cooling feeder hoses at source downstream of Y connector;

On port side disconnect or remove:
· cable tie holding bundled cables that plug into airbox;
· wire plug at bottom of airbox, if airbox is not removed;
· cam position sensor connector;
· 2 ground leads on oil cooler;
· oil pressure connector;
· throttle cable;
· cooling water hose clamp;
· 2 hose clamps on rubber connector between pipe outlet and water lock.

At front disconnect or remove:
· engine temperature sensor coupler;
· engine thermoswitch coupler;
· pickup coil coupler;
· lighting coil coupler;
· pilot water hose connector;
· fuel pump switch connector;
· fuel hose connector;

Optional: disconnect and remove airbox:
· vent tube into airbox;
· airbox;
· disconnect plug for injectors, etc. at bottom of airbox

Underneath disconnect or remove:
· 4 engine mounting bolts;
· shims (keep shims organized for re-installation).

Engine is now ready to be removed.

 

[Scottintexas]

Check coupler clearance** Very important to prepare for shimming, if necessary;

are we measuring the coupler clearance for fitment or measuring to place a shim underneath it for support when disconnected ?

 

[WREKS]

This is for fitment. The best time to do it is when removing the engine. The clearance can be measured and whether to add or reduce shims can be determined for when the engine is reinstalled.