3.0 litre merc coupler bumpers

[ancient mariner2]

Hello Members, Can ANYONE in this forum tell me if the coupler bumpers(3), are critical to the operation of my 3.0 Mercruiser ? Reason for asking is that brand new engine installed by boat mechanic, left out bumpers that sit on the underside of the coupler to help dampen the vibrational forces on the coupler, thereby offering a cushion to help avoid stress cracks in coupler plate. These bumpers are not seen on bigger engines, but 4 cylinder engine torque was obviously a concern for engineers developing this power plant and its stressors. Just trying to get someone with knowlege of couplers to tell me if I “absolutely” have to remove just installed new engine and mount the three little rubber bumpers. Thanks in advance for answers and helpful info.

 

[kenny nunez]

They were put there for that very reason. I would not be surprised if caused a “rattle” sound without them.

 

[harringtondav]

These bumpers are not seen on bigger engines, but 4 cylinder engine torque was obviously a concern for engineers developing this power plant and its stressors..

These inserts are installed on larger Merc engines. I helped my pal replace his '94 350 mag's coupler. The instructions were clear on requiring they be installed. I'd pull the engine now vs later. Later will likely mean replacing more parts.