Mercruiser 4.3L Rear Engine Bushings

I recently had the engine coupler fail on my 1989 Mercruiser 4.3L with engine serial number OC665952 and drive serial number OC717595 so the engine has to come out. I plan to replace all items on the rear of the engine since the engine is out I have purchased all part. The question I have is, I have purchased new bushing for the rear fly wheel cover engine mounts they are the old style without the serrations and require the double wound lock washer. Can someone tell me if there is a up or down for these bushings one side has white paint them but other than that they look the same from one side to the other.

Its been a while since I've done the old style rear mounts...going off memory, there's a spacer that has a chamfered - that mates with the edge on the mount...so that drives orientation...and the spacer goes in first...

Is there an up or a down position of the bushing?

But this is bull

The knurl will preventmount windup when tightening the rear mount bolt to the nut in the inner transom plate.
There is no top or bottom using the old mount

I have new old style bushing and double wound lock washers. Is there any reason I should not use those and purchase new style with the serrated bottoms?

Nope, they will work just fine.You have to wonder that after all the years of the doublewounds some engineer decides to save $.03 cents. Old school stuff works very well all these years. See no need to change

Well I finally had a chance to pull the 4.3L engine from my 1989 Sylvan and replace the rear bellhousing isolator mounts it looked like one of them was sagging about .125" lower than the other, the mounts were NOS older mounts without the serrated bottoms and I installed new double wound washers. I also replaced the coupler as the old one had stripped the splines late last summer and figured while was that far and the engine was staring me in the face it would be a good time to replace the starter as well. As I was aligning the engine I was required to raise the front of the engine to the point I am running out of threads on the mounts previously it was at about mid-point on the threads. Do I just add a shim plate under the mounts and keep going higher? Am I having to go so high on the front mounts because the of the new rear mounts? Any help would be appreciated.

Providing the gimbal bearing was installed correctly and the rear mounts were installed correctly you should not have to move the engine that much to get correct alignment. I would have tapped the alignment bar around its axis to align the gimbal to the coupler. Simply installing a bearing dies NOT align it

Hello Fellow Boaters I recently had to do some repairs on our boat and while doing so I found that the exhaust shutters in the "Y" pipe had worn and fell out. I had no issues getting the old ones out of the "Y" pipe and replaced with new style with the plastic oval retaining ring frame. My issue is that at around 2000 rpm's I am getting a shuttering sound/vibration on the right side exhaust it kind of sounds like a helicopter I believe that at a certain RPM the shutters hit a harmonic zone that makes the noise. Has anyone else had this issue and how can it be solved.