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Replacing engine mounts

8K views 25 replies 11 participants last post by  johnharch 
#1 ·
The engine on YANKEE is a Yanmar 3JH2e. I want to replace the four engine mounts and will order two #100 and two #150 mounts from the Yanmar dealer. The bolting looks straight forward. I am not so sure about how to lift the engine. I assume I have to hoist the engine about two inches to free the installed mounts and to push the new mounts in. Has anyone done this? Any advice? I do not see any lifting lugs on the engine.
Thank you.
Wolfgang
1994 PSC34 #274
S/V YANKEE
 
#3 ·
I just replaced mine earlier this summer and used a combination of 2x4s and a cheap chain fall that I found at Harbor Freight. However, before I started lifting anything I carefully measured the height of each mount with a caliper so that I could get it back close to alignment afterwards. I had to take the measurement differently for each mount due to the clearance for the caliper, so I made pen marks on the struts and engine beds to get the caliper in the same exact spot later and also took photos with my phone for each one. The pictures helped out immensely because it was hard to remember exactly how I held the caliper or what I was measuring from in the first place. This part worked out better than I had expected and after changing out all the mounts and returning them to the previous measurements my engine was almost perfectly aligned. (In the second attached picture you can see the pen marks on the mount and engine bed in an effort to return the caliper to the exact same spot later.)

As for raising the engine I slowly raised the engine to within half an inch of the top of each mount bolt by turning the bottom nut on each mount. Don't forget to disconnect the driveshaft! Then with the help of one other person, I had them leverage the front of the engine up with a 4 foot 2x4. Because the engine was raised first with the mounts, you only need to raise the engine an inch to swap mounts. I left the rear top nuts loosely on the mounts so that the engine would pivot off the rear mounts and not lift off of them by mistake. For the rear mounts I used a small chain fall attached to the engine lifting point. I used a 4 foot 4x4 spanning across the cockpit seats to attach the chain fall. The chain fall worked well and had a reverse feature to slowly lower it back down when done. While swapping mounts I put a couple of small 2x4 pieces under the oil pan to keep the engine from falling if the chain fall failed. Afterwards when lowering the engine I couldn't understand why the engine would not go all the way down on the mounts - as it turned out I forgot to remove the 2x4s.

I also learned that a standard length box wrench wrench was a bit long to adjust the rear mounts and was barely able to turn the nut. So I bought another wrench and chopped it in half on the chop saw. This stubby wrench worked much better and allowed for much more room to work.

Hope that helps,
Brian
 

Attachments

#4 ·
Brian,
Thanks for sharing your experience. It will help me tremendously. I was looking for lifting lugs and couldn't identify any. I will look for the lifting point again.
I enjoyed your website which was mentioned in the water heater removing post. In that post I noticed that you modified the control board. I would be very interested how that was done because YANKEE's has started falling apart.
Fair winds.
Wolfgang
 
#5 ·
Wolfgang,
The lifting point is a smallish metal loop, for lack of a better description, on top of the engine.

As for the engine panel, we should have our website updated in the next day or so with more detail. In short, I made a new external panel using starboard, and made a wood box for an internal panel mounted just inside the companionway. The inside panel now houses the start switch and horn and is easy to use out in the cockpit. I had to splice and lengthen those wires but otherwise pretty straight forward.

-B
 
#7 ·
I went to a bone yard, and bought the best looking Honda Civic scissors jack that I could find for $10. The jack folds down to about 1½" and can raise to over 8".

I was able to slip this in between the motor mount, and the hull with a ½" piece of plywood under the jack to spread the load.

I then removed the top nut on the motor mount, and the two bolts that held the bottom of the mount to the FRP stringers that hold the engine mounts in place. On many boats, these are lag screws, but on my boat, the etringers are hollow, and the mounts were through bolted.

After the mount was removed, I set the new mount to the same height as the old, and installed them.

Worked great.
 
#8 ·
We replaced our mounts in much the same way as Brian did. It was much easier than we had imagined (feared). We used a 2 x 4 to lever the engine up to replace the front mounts. Our method for lifting the rear of the engine was not as sophisticated as Brian's. We used a 2 x 4 and a piece of rope! One end of the 2 x 4 was short on one side of the rope fall and long on the other, making a lever and giving me some mechanical advantage. I lifted one end of the 2 x 4 while Rhonda slid in each mount. Only took a few seconds each.

Dave
 
#10 ·
I hired YES Yacht Services in Kemah, Texas to replace one of my mounts. They sent out a tech who decided replacing it was just too hard, so he left without doing anything as far as I could see. They then billed me for the part and two hours of labor. $350 total as I recall.

I recommend doing your own :)

I also recommend not working with YES.
YES = NO
:confused:
 
#11 ·
I just replaced mine this spring. It was far easier than I anticipated and I did them alone. I used a lot of short 2X4 blocks and one long 4X4 for a leaver. By putting the 4X4 leaver under the front end of the engine and blocking appropriately, I was able to sit on it and lift the engine enough to easily replace both front mounts. For the rear mounts, I ran the 4X4 across the seats, tied a rope from the center of it to the the coupling on the rear of the transmission. Then by lifting the ends and putting 2X4 blocks under the ends of the 4X4, the engine was raised and the mounts easily replaced.

Don't forget to uncouple the shaft first.

Tips: ( that I learned too late)
1. before starting, mark the outline of the base of the mount with a sharpie. Positioning the new ones will then be a breeze.

2. Don't move the bottom nut on the mount. Then when you get the old ones out, you can easily set them side by side with the new ones and adjust the height of the new ones before installing them.

3. Make damn sure you have exactly the right mounts before starting. Check the stud diameter and length to make sure they are the same--and of course, the numbers.
 
#12 ·
John,
Thanks for sharing. I am very grateful to all the skippers who have contributed to this thread. Meanwhile I have received the mounts from the Yanmar dealer. They look ok. Next week I am going to install them applying all the good stuff I have learned from you and the gang. :)
Wolfgang

S/V YANKEE
PSC34 #274
 
#13 ·
We did this for Kenlanu two years ago.

Getting the nuts and bolts loosened was a MAJOR headache, involving the biggest Makita impact wrench I've ever seen! To lift the engine we put a strap around the boom, put the main halyard around the boom right next to the strap, and lifted with a come-along. Lifting the engine was blissfully easy as was the rest of the re-installing. Best of all Kenlanu purred like a new boat!

Jay
SV Kenlanu
Buck's Harbor, ME
 
#14 ·
Here is a summary of the engine mounts replacement on SV Yankee:

On Brian’s (SV Indigo) advice, I measured the actual position of all four engine brackets in horizontal and vertical direction and marked the footprint of each engine mount on the stringers. I wrote the required height of the supporting nut on each new mount after I marked them with port/starboard and front/aft. That saved me tons of time for the alignment after the new mounts were installed.
I also identified the two lifting lugs. The forward lug is a bit to port, located adjacent to the motor oil filling cap, the aft lug is more to starboard near the air intake.
First I disconnected the coupling bolts and took off the four nuts on the engine brackets. Since the shaft seal is a PSS type, the rubber bellow acts like a spring pushing the coupling tight against the engine. I moved the PSS rotor on the shaft about ¾” toward the engine to release the tension. Then I separated the coupling halves and put a ½” wooden board between the faces of the coupling. That way the coupling could slide on the wood when the engine was lifted up.
Next I tackled the forward mounts because they are in easy reach from the cabin. All screws came loose without any problem. For lifting, I attached a shackle (biner) to the forward lug and connected it with a web string to a 2x6. The 2x6 was set across the cockpit and was supported on the cockpit seats. (Biner and websling are part of my mast climbing gear and the 2x6 is used as jerry can board). Then I pushed up the 2x6 with a pry bar alternating between port and starboard side. As elevation was gained, I put shims under the 2x6 to secure level. By lifting the engine up this way, I could take the old mounts out and slide the new mounts in aligning them to the marks. The alignment nuts of the new front mounts were preset to the noted elevation. I re-installed the screws and lowered the engine.
The more difficult part was to hoist the aft of the engine. The lifting lug is offset to starboard. Lifting the engine using the described method, left the port side of the engine sagging. I also had to unscrew the raw water filter, the muffler, and part of the raw water hose so that these parts could tolerate the lifting movement. I rigged another websling to the aft port engine bracket and used a 2x4 to bring it up. I could take out the old mounts and put in the new mounts. The new aft mounts were preset to the noted level. A good marking of the old mounts’ food print saved time with horizontal alignment.
After the engine was lowered down on the new mounts, I took control measurements of the engine brackets to calculate what alignment would be needed. I moved the engine vertically by using the adjustment nuts and horizontally with a 2x4 until I was in the range of the previous measurement. Then I removed the board between the coupling halves and got the coupling back in place. I had to tensioning the PSS at the same time to avoid water coming in. The new mounts were preset pretty good. I could center the coupling halves with hub and bore immediately. There was only a vertical alignment necessary.
Since I work faster with the metric system, the alignment calculation is done in metric. I measured a gap of 0.35 mm at top of the coupling. Zero gap at the bottom. The diameter of the coupling is 100 mm. The distance of the engine mount is 412 mm. The thread pitch on the bolt of the engine mount is 1.5 mm. Applied all this, a full turn of the engine mount alignment nut corrects the coupling gap by 0.36 mm. So I did, using the front mounts of the engine. After the alignment I could not get a 0.1 mm feeler gauge in anywhere.
Next I mounted the washers and nuts on the engine brackets. When torque is applied to these nuts the mounts can twist easily. I hold the fixed nut at the top of the u-shaped mount with a 24 mm wrench to offset the twisting force. Finally I checked the coupling gap once more and installed the four coupling bolts.
Manpower: 1 person
Tools: Short 24 mm wrench, 24 mm bit, 14 mm bit, extension, ratchet, feeler gauge, screw drivers, Allen wrenches for PSS and split collar, wrenches for coupling bolts, 15” pry bar.
Auxiliaries: 2x6 spruce, 2x4 spruce, wood shims ½”, 1”, 2”x4”, 2”x6”, 4’ web slings, shackle, split collar for 1” shaft to work PSS rotor.
Purchase: 2 engine mounts #100, 2 engine mounts #150. Genuine Yanmar. Total cost: $550.
Wolfgang
SV YANKEE PSC34 #274
 
#15 ·
Wolfgang,
Nicely done. Glad the measuring trick worked, but doing the job yourself must have still been a good workout - going from scrunched down in the engine room to measure the alignment to climbing out and over and down into the boat to make a small adjustment, and repeat a few dozen times more.

Out of curiosity, did you happen to look at the old mounts. Yanmar specs say #100s on one side and #150s on the other, which is what I replaced mine with. However, I discovered that the old ones were #200s one three legs with a #150 on the last one. I'm not sure if they were original or had been replaced by a previous owner. I tried to think of a rational reason for doing it that way, but it defies logic. I'm guessing that whoever installed them just used what was laying around at the time.
 
#16 ·
Brian,
I believe I removed the originally installed mounts. The engine has run only 600 hours. I could still read the 100 on the starboard and 150 on the port mounts. The front mounts were very rusty. I don't see a good reason to come up with 3 x 200 and 1 x 150 setup other than jerry rigging.
Wolfgang
 
#17 ·
WARNING!: REPLACE THE SET SCREWS ON YOUR PSS SHAFT SEAL ROTOR!! Do not re-use the set screws.

The set screws are meant to be used only once. If you re-use the same screws, the rotor will loosen, and your bilge pump will likely get a workout.
 
#18 ·
A Canadian yacht had to be abandoned and the skipper rescued off the Great Barrier reef last year, when his Yanmar mounts all broke, and his loose engine bashed a hole in his hull. I have heard other stories about Yanmars breaking loose from all their mounts simultaneously, leaving the engine rolling dangerously in the bilge. They have nothing but rubber holding your engine in. You would be wiser to go for Perko mounts, which are not dependent on rubber alone for holding your engine in. If you have new Yanmar mounts, a bit of chain to stop your engine from breaking loose completely would be a good safety factor.
 
#23 ·
I have had one mount fail under my 3HM35F Yanmar (front port). It was not the rubber to metal bond that failed, but rather the engine mounting bolt which cracked through just above the point where it joined the upper metal plate. It made a ticking noise when the engine idled. The surveyor heard it before we bought the boat, but he could not locate the source. We found it 6 months later. I replaced all four. Later when we had the engine rebuilt, I replaced all four mounts again with no indication that anything was wrong with the existing mounts.

Bill Murdoch
1988 PSC 34
Irish Eyes
 
#25 ·
The forward port engine mount was broken when we bought Irish Eyes. At that time the engine drive refrigeration compressor was missing. (The hoses and clutch wire had been cut and hidden.) The compressor had previously been installed on the starboard side of the engine about even with the 3HM35F injection pump on brackets attached to the injection pump bolts. In that location it rubbed on the fuel fill line and blocked access to the dip stick, the small engine fuel filter, and the priming lever on the engine fuel pump. When I reinstalled the compressor a year or so later, I made a new bracket and mounted the compressor above the engine and to port just above the spot where the Yanmar factory alternator mounting bolt goes.

Bill Murdoch
1988 PSC 34
Irish Eyes
 
#26 ·
My compressor is also on the port side. the bracket is really strong, but is mounted to everything. Two of the water pump bolts, one head bolt, the forward port motor mount and two bolts into what appears to be the where the original rear motor mounts were on the engine.
 
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