Engine mount help!

[Newbiechris]

Hi guys bought my boat at the beginning of summer it is a 98 Four Winns horizon rs Anyway I noticed my engine mount lags where crooked I checked if they where tight all except one snug up one just won't grab I took it out and looked for any rot from what I could see it looked fine and it looks like the lags have always been crooked. How do I go about fixing this I'm worried to use the boat the last thing I was to do is cause more damage I'd like to redo all 4 lag bolts and want to know how to go about it

 

[Ned L]

Even though they may not look great, as long as they tighten ok I wouldn't be too concerned. For the lag that just spins I would pull the lag and epoxy in a dowel then re-drill and reset the lag screw. Engine mounts on inboard-outboards do not carry nearly as much load as engine mounts on an inboard.

 

[Rickmerrill]

#3 Mine are the same. I just assume they installed the engine and then drilled. With the engine in the way that's as close to vertical as they could get it - don't know why they don't use a 90 degree drill. Guess it doesn't really matter, heck it may be harder for it to pull out at an angle. If one lag won't tighten that would make me want to make darn sure I know the engine support wood is all good. If so then the glued dowel is a good fix.

 

[Condor1970]

In my case, I got lucky. The front lag bolts that hold the front motor mount to the hull, were bolted to a thick cross member that just happened to have a small space under it for the bilge water to drain aft.

I decided to simply toss the lags in favor of long stainless 7/16 x 4" machine bolts. Then, drill all the way through the cross member, and use the long stainless bolts with lock nuts and big washers to bolt the engine mount in place. It will never move or come free again.

 

[tpenfield]

The biggest issue is to make sure the wood core of the mounting stringer is really dry. Otherwise the remedies mentioned won't work, and you may be looking at further deterioration that impacts the other bolts .

 

[Woodonglass]

This ^^^ is Correctamundo!!! If the motor moves and comes out of alignment with the outdrive...THAT's AN ISSUE!!! I'm sorry NEDL but I/O's can move quite a bit with the tossing and turning from hard turns and bouncing in waves and wakes on rough water especially if the mounts are loose. You want everything to be tight, secure and aligned well. That's this Old Dumb Okies opinion. Do with it as you will

 

[Ned L]

Ahhh, .. I didn't say they don't have to be secure. I said "Engine mounts on inboard-outboards do not carry nearly as much load as engine mounts on an inboard." Engines in both types of drives (I/O's & inboards) are equally subject to the same "tossing, turning and bouncing" from the motion of the boat. In an I/O the thrust of the prop that actually moves the boat forward is transferred through the lower unit to the transom (not to the engine). In an inboard EVERY bit of thrust required to move the boat forward is transferred through the prop shaft to the thrust bearing in the reverse gear, through the engine, through the engine mounts and to the engine beds. (It is the engine mounts that "pull" the boat through the water.) Failure of the engine mounts in an inboard can (and has) allowed the engine to push itself forward until something stops the movement (often times the prop jamming itself into the deadwood under the boat). This can't happen on an I/O. .... So which would require more 'strength' (?) keeping an engine from bouncing around, or that plus holding hundreds + of horsepower of thrust stationary?

 

[Scott Danforth]

the reason the lag bolts are in at an angle, is the factory method of installation is set motor in place, rough align, quickly drill 4 holes (sometimes) and hit the lags with an impact gun, then align.

with that method, you can not get the lag bolts vertical.

 

[Woodonglass]

Ahhh, .. I didn't say they don't have to be secure. I said "Engine mounts on inboard-outboards do not carry nearly as much load as engine mounts on an inboard." Engines in both types of drives (I/O's & inboards) are equally subject to the same "tossing, turning and bouncing" from the motion of the boat. In an I/O the thrust of the prop that actually moves the boat forward is transferred through the lower unit to the transom (not to the engine). In an inboard EVERY bit of thrust required to move the boat forward is transferred through the prop shaft to the thrust bearing in the reverse gear, through the engine, through the engine mounts and to the engine beds. (It is the engine mounts that "pull" the boat through the water.) Failure of the engine mounts in an inboard can (and has) allowed the engine to push itself forward until something stops the movement (often times the prop jamming itself into the deadwood under the boat). This can't happen on an I/O. .... So which would require more 'strength' (?) keeping an engine from bouncing around, or that plus holding hundreds + of horsepower of thrust stationary?

Nope and I did not intend to offend. This is and Excellent description of how both I/O's and OB's work. Thanks for taking the time to educate us all!!! Sorry for the misunderstanding. After re-reading everything I did a poor job in my previous post!!!:facepalm:

 

[Ned L]

No problem WOG! There is also another force in play that the same for I/O's and inboards. This is the force of the engine torque on the motor mounts, this is the same force as in a rear wheel drive car or truck, where the torque tries to pick up one side of the engine. As I said , this is the same for I/O's and inboards so I didn't mention it before. One one boat I have (Jersey speed skiff - 16 ft skiff with a Chevy 350 inboard) I can actually make the boat rock back @ forth standing still with the engine torque by hitting the throttle.

 

[Newbiechris]

Even though they may not look great, as long as they tighten ok I wouldn't be too concerned. For the lag that just spins I would pull the lag and epoxy in a dowel then re-drill and reset the lag screw. Engine mounts on inboard-outboards do not carry nearly as much load as engine mounts on an inboard.

Can I try a slightly larger bolt or is it better to fill and re-drill? Also any idea how tight the lags should be I don't want to over tighten and cause more problems Thanks for all the help guys!

 

[Ned L]

First off, sorry about the typos & grammar in my reply above, it is still tough to post from a phone since the forum "upgrades". You could go with a larger lag screw, however that does move you in a direction of less options in the future (you can always make the hole larger, but it is more work to make it smaller). If it was me I would try to keep the same size. How much to tighten it is a good question, it is quite easy to over tighten and strip lag screws. I tighten them until they bottom out (pretty easy to see and feel) and then go maybe another 1/8 turn, maybe 1/4 turn max.

 

[bigdirty]

What I have seen done in this situation (assuming your mounts aren't wet/rotten) is this; take an angle drill with a bit roughly the size and length of the bolt and run it into the stripped hole, and around in a circle as best and as much as you can. Vacuum out as much as you can with a shop vac. This will leave you with basically tear-drop shaped 'hollow' inside the glass of the engine mount. Fill with thickened epoxy. Once epoxy is set, pilot/pre drill accordingly with your angle drill so you can get as straight as you can, and run the mount bolt back in tight. I've seen this kind of repair last for years.

If the boat is on the hard, i would pull the drive, and check motor alignment with the tool after its all epoxied up and mount bolts are tight. The coupler on the back of the motor will take a bit of misalignment for a short time, but if it fails out on the water, you're gona have a bad day. Better to check it while you can IMO