Engine Mount Holes: Anything to be done before putting the engine back in?

[San_Diego_SeaRay]

I?ve spent the past few months taking apart, grinding off rust, painting, then putting back together a 1993 Bravo 7.4 engine. The boat is a 1993 27? Chaparral Signature. It?s getting near the time to put the engine back in, and I?ve been wondering about the engine mount holes. There must have been some add?l looseness created by removing the lag bolts. And I?d like to ensure that the engine is as secure or even more so than before I removed the engine.

The lag bolts are about 3? long, and I would say they?re about 3/8?; maybe 7/16?. I was thinking about mixing up some thinned ?peanut butter? resin (thinned w. styrene) w. ?? chop strand and Cabosil. Then pouring it into the old holes, then drilling a pilot hole about ?? and driving the lag bolts back in. My fear would be that the mixture would cure to a ?cold joint? and the whole plug might come out with enough stress. What do you think? How would you approach this? Is lag bolt looseness even a concern?

 

[alldodge]

I would drill the holes out to 1/2, then fill with M-Tek or 5200. Drill 15/64 for 3/8 or 9/32 for 7/16

 

[Scott Danforth]

I would drill larger in preparation for epoxying in some plugs, and check the shavings. wont be the first boat with wet/rotting motor mounts.

if the shavings are light colored, dry and smell like wood, then drill out large enough to epoxy in some plugs

if the shavings are dark colored, wet, and smell like rotten leaves.....then you have some fiberglass work replacing the mounts prior to putting the motor back in your boat

 

[jbcurt00]

Just make sure the motor mount stringers are in good shape before drilling, tapping or lagging the newly redone motor into them...

Some 'loose' lag screws arent loose so much as mounted to soft stringers......

It is a nearly 25yr old hull.

 

[tpenfield]

+1 on checking the engine mount stringers for dampness in the wood or even rot. It would be a bummer to have the engine mount 'cave in' after having done all that work on the engine.

 

[San_Diego_SeaRay]

I would drill larger in preparation for epoxying in some plugs, and check the shavings. wont be the first boat with wet/rotting motor mounts.

if the shavings are light colored, dry and smell like wood, then drill out large enough to epoxy in some plugs

if the shavings are dark colored, wet, and smell like rotten leaves.....then you have some fiberglass work replacing the mounts prior to putting the motor back in your boat

Good point. I've spent the past 3 days in that bilge trying to clean it up. No evidence yet of rot but I'm going to be getting lots of samples. That's because I'm also going to be fixing about 30 - 40 screw holes used for wires, trim pumps, etc. I'll have to drill out each one to make it wide enough to receive whatever I decided to fill it with. Fingers crossed for nothing but light colored shavings...