I installed my new motor mounts, have a question

[kito]

I bit the bullet and bought 4 new yanmar motor mounts for my ysm12. I found out on 2 of the old ones, the studs were broke off and were just bouncing on top of each other. No wonder it was like a paint shaker. Anyway, the new mounts matched the old bolt pattern perfectly. Problem is Hunter used lag bolts. 6 of my new ss 3/8" lag bolts went in fine and got them torqued down good. 2 of them are within 1/8" of being tightened before they spin. Next size is 1/2" and would mean drilling out the mounting feet and worse....pulling the motor out to get access for my drill. Any tips/tricks to get my 3/8" lag bolts torqued down and allow easy removal later? I thought about dipping a few toothpicks in epoxy and putting in the holes and let dry.
Btw, I fired up the engine and dang what a difference these mounts made.

 

[justsomeguy]

Couldn't you use threaded inserts and bolts?

But seeing as how you're most of the way there with the lag bolts, you may be able to jam some stainless steel wool into the offending holes?

 

[kito]

Couldn't you use threaded inserts and bolts?

But seeing as how you're most of the way there with the lag bolts, you may be able to jam some stainless steel wool into the offending holes?

SS wool......does that work well? Never tried that. I do like your threaded insert idea too. Something Hunter should have done in the first place. Not a fan of lag bolts on a boat. Thanks for the info.

 

[justsomeguy]

It works in smaller screws that have stripped out. I'd try to distribute it as evenly as possible along the length of the screw.

Good luck with the torquing.

And, you're welcome!

 

[svchickadee]

Prep the holes properly, fill with epoxy w/silica filler and drill to correct size.

 

[rardiH36]

Prep the holes properly, fill with epoxy w/silica filler and drill to correct size.

This is a good approach ... unless one can't drill straight down into the hole without removing the engine first ... which was my dilemma.

I posted my experience with your situation way back in 2008. Totally DIY doable. Seven years on from the repair, my lag bolts are still holding firm. Here is the link to my full description of the steps I did. It's post #5 in the thread:

http://forums.hunter.sailboatowners.com/showthread.php?p=550895&highlight=motor mounts

 

[svchickadee]

Good approach. Epoxy will not adhere to grease. Greasing any mount, etc outside the hole will prevent any overflow epoxy from sticking.

 

[kito]

This is a good approach ... unless one can't drill straight down into the hole without removing the engine first ... which was my dilemma.

I posted my experience with your situation way back in 2008. Totally DIY doable. Seven years on from the repair, my lag bolts are still holding firm. Here is the link to my full description of the steps I did. It's post #5 in the thread:

http://forums.hunter.sailboatowners.com/showthread.php?p=550895&highlight=motor mounts

Thanks for the link Rardi36. Epoxy with Teflon tape around the lag screw sounds like a great idea too. Gotta love this place for tips.

 

[Ron20324]

Might the bolt be too long, and is bottoming out before being tight, and thus stripping the hole threads?

 

[kito]

Might the bolt be too long, and is bottoming out before being tight, and thus stripping the hole threads?

Good point. I used the same length on my new lag bolts. The old mount had a 1/2" thick bottom flange. The new one is only about an 1/8" thick. I figured the new lag bolt would cut some new threads on the bottom. Apparently Hunter didn't drill the tap hole any deeper than needed. I am thinking about adding some stiff isolating material under each foot anyway. Not sure why Yanmar changed to such a thin flange.

 

[Claude L.-Auger]

Good point. I used the same length on my new lag bolts. The old mount had a 1/2" thick bottom flange. The new one is only about an 1/8" thick. I figured the new lag bolt would cut some new threads on the bottom. Apparently Hunter didn't drill the tap hole any deeper than needed. I am thinking about adding some stiff isolating material under each foot anyway. Not sure why Yanmar changed to such a thin flange.

Not sure I understand Kito: if old mount had 1/2" thick bottom flange and new one only 1/8" what does that do to your alignment ? On a friend's boat we solved that problem by using a 3/8" starboard piece drilled to match the holes in the mounts. That raised engine back to where it was, thus ensuring proper alignment and also prevented screws bottoming out. Good luck. Claude

 

[kito]

This is a good approach ... unless one can't drill straight down into the hole without removing the engine first ... which was my dilemma.

I posted my experience with your situation way back in 2008. Totally DIY doable. Seven years on from the repair, my lag bolts are still holding firm. Here is the link to my full description of the steps I did. It's post #5 in the thread:

http://forums.hunter.sailboatowners.com/showthread.php?p=550895&highlight=motor mounts

I wonder if the 2 part epoxy that comes in a syringe at Home Depot would work. My old lag screws came out dry as a bone so no moisture to worry about.

 

[kito]

Not sure I understand Kito: if old mount had 1/2" thick bottom flange and new one only 1/8" what does that do to your alignment ? On a friend's boat we solved that problem by using a 3/8" starboard piece drilled to match the holes in the mounts. That raised engine back to where it was, thus ensuring proper alignment and also prevented screws bottoming out. Good luck. Claude

The new mounts are taller as far as where the adjustment stud comes out of the rubber. I just eyeballed the old with the new and adjusted the nut to an approximate location. Good thing about the new ones is the bottom nut is only about a 1/2" up the stud compared to about an inch on the old one. I like being lower on the stud than higher. I haven't installed my new prop shaft yet but plan on next weekend. With help from my good Buddy, dial indicator and feeler gauge we should get it align pretty good.

 

[Chris Patterson]

I wonder if the 2 part epoxy that comes in a syringe at Home Depot would work. My old lag screws came out dry as a bone so no moisture to worry about.

That two part epoxy will work fine. Stick with Permatex or a quality brand though.

And it is common to see these engines held down with lag bolts. The one that got us though was the Nanni diesel we hauled last year with machine threads on it, screwed down into the beds. How in the world that motor stayed in there was a shock to us..

 

[Alan Gomes]

SS wool......does that work well? Never tried that. I do like your threaded insert idea too. Something Hunter should have done in the first place. Not a fan of lag bolts on a boat. Thanks for the info.

Not sure if this would work, but as a variation of the SS wool idea, how about cutting some strips of stainless steel shim material: http://www.mcmaster.com/#catalog/120/3789/=tpz9ea

You can get it in a variety of thicknesses. I've never thought of it for this application but perhaps it would work.

 

[Rick Webb]

Stainless Steel Wire

Similar to the toothpick idea. I think I would do that in addition to the epoxy.

 

[woodster]

Re: Stainless Steel Wire

get some lead shields from the hardware store and put them in the hole ...then put the screws in a tighten them up

 

[RAD88]

Where did you buy the mounts, how much did they cost and are they identical to the old mounts? I am looking to do the same job this winter.

 

[RAD88]

Oh - by the way I like the epoxy syringe or the lead shield approach.

 

[kito]

Where did you buy the mounts, how much did they cost and are they identical to the old mounts? I am looking to do the same job this winter.

I got mine at Toad Marine. One of the few places that carry them. Yanmar is very proud of these mounts at $107 each. Glad I did though. These mounts are designed for my ysm12. Here's a link of what I got https://shop.toadmarinesupply.com/s...esults&pn=124070-08341&storetype=mdd&x=9&y=13