Solid Motor Mounts

[Bruce2]

I have a 1995 Merc 135 carbureted outboard and would like to know the pro's and con's of solid mounts....thinking about making a set out of Delrin(plastic type material)... Thanks

[phillnjack]

I have asked this same question all over the net and it seems everyone likes them.
The one and only con is a slight bit of vibration in the boat, but other than that they are better. y
ou can even buy solids from mercury so they are definitely ok to use.
steering obviously better, and handling better when you come off the throttle at high speeds.
I have a omc and have made a solid mount for the top and a couple for the bottom, just have to fit them now. (winter is here so will fit ).

Mine are from a bit of billet alloy but I see no reason not to use a real good strong plastic like delrin.
I am pretty sure there are a good few out there that have delrin mounts.
hope to see some definitive answers on this, its a good subject.

.

[Glasstream15]

I've had solids in my InLine for 20 years. I don't think i'd ever had another boat without them. Even though my boat is mostly 55 MPH and occasionally I have seen 59 on my GPS, it made such a difference that it's fun to run WFO now. Really wasn't before.

[phillnjack]

20 years is good going, that alone is proof that they last

[Bruce2]

I'm concerned i guess about the vibration aspect...... i have to back out of it at 63 mph gps because of it being hard to control....Motor is on a 1989 Champion 17'6" bassboat and i'm turning a 25m prop 5600 @ 63 and still have some left in it...the vibration factor was another reason thinking about going to Delrin thought maybe it would have a little absorption to it than metal.

[outasite]

In thirty five years I've never run anything other than solid mounts on Merc V6s.Ive never had a problem with vibration,what little there is,just seems normal to me! Do it! You won't be sorry.

[Glasstream15]

If you notice any extra vibration, it'll just let you know the motor is running. I've just never noticed it at all but maybe an InLine is smoother than a V.

[phillnjack]

I think the Delrin will give the same amount of vibration as billet aluminium to be honest.
Both will need to be tightened up so no slop at all ( thats the whole point of solid mounts) and both will give similar vibration.
If the Delrin was to be of a noticeable amount better as in anti-vibration then it wouldn't be doing its job .
Many parts in automobile bushing are now being made from Delrin, so its obviously a very tough plastic/polymer, and would be better for ant-corrosion properties.
you can get Delrin with ptfe impregnated too nowdays, so it would also have good anti seize properties.
COST would be the limiting factor of either material, what is cheaper ? Delrin or Billet 6061 5075 etc.

whatever you choose its going to be a better controllable ride at full throttle than soft rubber mounts.
ive watched so many engines on you tube showing their jack plates etc, I watch the actual motor to bracket and cannot believe how much movement some of these engines have.
this puts a lot of strain on the transom on the jackplate and on the brackets of the engines, its like a constant smash with a big hammer all the time when water is a touch choppy.
even with just 2 lower mounts pinned my engine behave much better.

[vnemous]

I find I can lessen the vibration of my 300x solid mounts by trimming all the way down and give it on up bump to to get it off the saddle. This is only at idle of course

[Bruce2]

Bob's machine sells the steel mounts for 95 bucks a set of 4, the delrin i can get a 2 foot stick for around 35 bucks and my Brother is a machinist. After doing much googling i have found that Yamaha has solid mounts made out of Delrin available. Thanks everyone for your input...

[David - WI]

I've had both.

Solid mounts seem to accelerate the wear and deterioration of the steering, tilt and trim ram bushings; there's nothing worse than vibration for a shaft & bushing when they aren't turning. Rubber mounts help damp out the engine vibrations before they get to the bushings in the mid.

Solid mounts made a huge difference on my chine-walking Checkmate, I just wouldn't spend the money on them unless I actually needed them. I have two mids here with oblong bushings and unevenly worn shafts that will cost $ hundreds to ream out and repair with over-sized bushings and new shafts. I'm probably going to try rubber mounts in my HST when I get one of these mids fixed up; since a napping monkey could drive that thing WOT anyway.

I would definitely check for play in all the bushings in the mid before changing motor mounts; if the bushings are getting bad then solid mounts will just make them get worse, faster.

[vnemous]

For you mercury guys the "stop slop" that chaz makes really tightens things up on the swivel tube. I got one and wow did it tighten things up and that was after I rebuilt my clamp bracket with all new bushings. Highly recommended.

[Bruce2]

Chine walking i can handle it is the prop whip lashing effect i get where is whips ass end of boat from side to side and if you try to drive thru it it only gets worst...you can see some of whats happening in this video...im turning a 23p old style trophy with double cup added in this video, i have since went to a 25m 3 blade and i think if i get this problems solved i should be in the mid 60's as i run 63 mph gps now.


https://youtu.be/8F0uGOEfqx0

[phillnjack]

I bet if you get on the floor and tug at the skeg when its on the trailer that engine will show up loads of movement left right and backwards forwards too.
I would check the thru tube bushings and if they are bad gets some nice shims made up from nylon or the Delrin to take out the slop. or slivers of titanium.
none of use check all the bushings often enough, I dont have the power most of you guys on here have, but even I have found a bit of slop causes terrible problems.

mine is not a fast boat like that, but I had that happening to me at just over 40mph with one particular prop, turned out it needed sharpening up a bit, then the left right jiggle went away.
might be worth a try if its not a very sharp prop.
since I sharpened that I sharpened all my props like razors and found all of them perform much better ?? might be imagination and wishfull thinking with the rest, but the bad prop
definitely got better and no wiggle from back end any more.
BUT thinking about it I did pin the lowers at the same time, maybe it was tightening up the lowers that helped ?

nice boat by the way.
.

[Bruce2]

I bet if you get on the floor and tug at the skeg when its on the trailer that engine will show up loads of movement left right and backwards forwards too.
I would check the thru tube bushings and if they are bad gets some nice shims made up from nylon or the Delrin to take out the slop. or slivers of titanium.
none of use check all the bushings often enough, I dont have the power most of you guys on here have, but even I have found a bit of slop causes terrible problems.

mine is not a fast boat like that, but I had that happening to me at just over 40mph with one particular prop, turned out it needed sharpening up a bit, then the left right jiggle went away.
might be worth a try if its not a very sharp prop.
since I sharpened that I sharpened all my props like razors and found all of them perform much better ?? might be imagination and wishfull thinking with the rest, but the bad prop
definitely got better and no wiggle from back end any more.
BUT thinking about it I did pin the lowers at the same time, maybe it was tightening up the lowers that helped ?

nice boat by the way.
.

Thanks i been working on boat, looked like crap when i got it, since that video i have installed new carpet.....I have run 3 different props on it and they all do it, it's been getting worst, it even starts that ass end whipping in the turns now..Bushing all seem tight, but bottom mount support has play on pivot tube and i think the upper mounts being sloppy and bottom mounts seem better it's wearing that bottom mount. Thanks to all that replied..