2006 Sea Ray 185 Motor Mount Repair Question

[AMMO DAWG]

I have a 2006 Sea Ray 185 Sport that I am repowering with a 4.3, previously had a 3.0. I had in the past removed and reinstalled the 3.0 and noticed one of the front motor mount lag bolts wouldn't tighten. I had asked in several places and contacted Sea Ray and never got a straight answer on the construction of these mounts. Lots of speculation related to no wood, but couldn't find anywhere for this year boat where someone had done a repair.

I decided best to tear into it to be sure there is something solid to bolt into before installing the new engine. Sure enough when I cut of the top there is a piece of wood inside, 1.5" lumber. There was rot when the bolt holes had gone in, guess water seeped in over the years. The starboard side wasn't so bad, the port side was shot. Odd part is the wood is not glassed to any other structure, It has foam below it and on all four sides, I assume the glass tower it self is the structure, the wood is an anchor for the bolts. I replaced the wood and looking for advice on how may layers of glass to use. I'm using 1708 with poly. The piece I cut out was about 3/16" to 1/4" thick. I attached some pictures. I was thinking four to six layers with several inches overlap.

Question for the experts, how much load goes into those front mounts with the rear of the engine firmly bolted into the transom plate? I know it's probably rotational, just never seen any posts where engine mounts had failed to a point of letting the engine shift or rotate. BTW, when I rebuilt the back end, gimbal housing the transom was solid with no rot. Looking forward to you advice.

 

[tpenfield]

You have got about 1/2 the weight of the engine and then the effect of torque, which will probably go 2-3 X the weight. Take 4 layers of 1708 cloth pressed together and see what your thickness is . . . you might need 6 layers to get up to the 1/4" that you spoke of . . .

You mentioned going to a 4.3 . . . are the front mounts for the 3.0 also going to work for the 4.3?

 

[AMMO DAWG]

Thanks, the donor engine had the proper 4.3 mounts, so I will be using them. Hindsight is a great thing, should just have bought a new boat with a 4.3, been a large project with a can of worms every turn of the corner. I think I'm on the home stretch!

 

[todhunter]

I feel like there was a thread on here in the last month where the poster took their new (to them) boat out on the first trip and blew the gimbal bearing because one of the forward engine mounts sunk.

 

[Baylinerchuck]

I feel like there was a thread on here in the last month where the poster took their new (to them) boat out on the first trip and blew the gimbal bearing because one of the forward engine mounts sunk.

Usually when the mount caves in and the motor sinks, the coupler gets destroyed. Most find that out when they try to align the drive shaft through the gimbal bearing into the coupler. It ain’t gonna go. An alignment bar would definitely point this misalignment out.
A buddy of mine poured SeaCast into his Rinker motor mount boxes for a permanent repair. Was a little pricey, but extremely solid, and no wood.