Installing the New Yanmar
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An Offer I Couldn’t Refuse; or, You Get What You Pay For. Note:
the names in this article have been changed to protect the guilty. As to
choosing the dealer and installer, I found that a local Yanmar
dealer, Morris Marine Service in |
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All of
the fuel and electrical lines to the old Volvo were disconnected and
labeled. The eight 10mm bolts holding
the Volvo to the bed were removed and the shaft coupling disconnected from
the trans. A wooden 6x6” timber was laid
across the open companionway, and a chain fall was hung from it. We sawed a slot into each side of the 6x6
to match the aluminum track for the companionway. This allowed us to slide
the 6x6 as needed without fear of the timber falling through the companionway.
The chain was hooked onto the Volvo’s lifting eyes, and the chain ratcheted
up until the old engine floated over the bed. We then slid the timber forward
and thus moved the engine onto a dolly forward of the bed in the salon. We
put the old Volvo on a dolly so that we could save money ($125/hour) |
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by requesting the yacht yard’s crane only once: the crane would hoist
the old engine out and then drop in the new Yanmar
in one shot. Actually, we had a
“triple play” with the crane: I had placed an ad on an Internet boating site
a few weeks earlier to sell the old Volvo for $500, and was flooded
with callers who were eager to buy it.
Interestingly enough, I was honest about the engine’s condition in the
ad, but that did not deter anyone- all had planned to rebuild the
engine. So the same day the engine was
pulled out by the crane, the buyer of the old engine came with a pickup and
thus shared the cost of the crane, since he needed to hoist the engine out of
the boat and onto his truck. |
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Above you see the old Volvo on its way to diesel heaven. The
3YM30 was dropped onto the dolly in the salon, out of the way while we
prepared the engine bed, new wiring, and fuel lines. We
measured the space on and around the engine bed. The Scanmar 35
bed is 16" on centers and 19-7/8" long. The maximum height
available for engine is 23", and the maximum length is 27-1/2" from
front to propeller shaft coupling. We
confirmed that the engine would fit nicely into the existing space, with just
a few modifications. One would be to cut through the bulkhead between the
engine space and machinery space (ender the cockpit) to allow room for the
tall exhaust rise, as seen at the lower right in this photo. Another issue
was that this engine is so much shorter than the Volvo,
you will probably need a new propeller shaft. We did, but that’s a sad story
which we’ll get into later. |
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The engine bed was unbelievably filthy, mostly with dirty, gummy old oil; it needed to be degreased several times before I could even begin to clean it. This picture was taken after the initial cleaning. The black semi0circular object is the stock Valeo “Paris-Rhone” regulator which is normally bolted to the back of the Volvo alternator. It was removed by the previous owner so a Weems & Plath “Automac” regulator controller could be installed. One of the primary reasons the engine bed was so oily was because there is no real drain in the engine pan. When the oil was changed, some leaked into the pan and stayed there, perhaps for years. One of the “features” of the Scanmars is that the boat has many mini-bilges or sumps which can trap and hold water. This is due to the fact the bilge area is criss-crossed with heavy fiberglass “floors” or “stringers”. It makes the boat very strong, but it does create a drainage problem. Either you need to have a bilge pump in each of these sumps, or they all need to drain into the main bilge area, the deepest sump of all, which lies just above the keelbolts. |
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This is
a closeup of the inner forward edge of the engine
pan. You can see that there is no real
drain, just a ragged hole which was probably made by punching with some sharp
instrument in the face of this fiberglass ”stringer”. There is a second hole
to the right of the first, even smaller than the first. I didn’t like this at all for a few
reasons. 1) Water which gets into the engine bed pan can’t get out until it
covered the engine’s oil pan and finally overflowed the cockpit sole; 2) it
is not known where water which makes its way into the hole can emerge on
either side of the hollow stringer. |
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I
decided to make a real hole in the forward edge of the engine pan through to
the other side of the stringer and seal the edges so that water can drain
into the next sump, but will not be free to slosh around inside the stringer
and wind up who-knows-where. Here you see the enlarged hole looking aft
toward the engine (which has been removed). |
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I
drilled a 7/8" hole in both sides of the stringer in front of the engine
pan to create a real, useful drain, and installed a threaded 3/4" PVC
pipe. As you can see in the closeup below, the hole is irregularly shaped and
off-center; this will need to be covered so water cannot enter the stringer
and slosh around. To the right, you
can see 4 of the tapped holes which held the Volvo mounts to the engine bed. |
Incidentally, in case you are wondering (as I was), the
grid structure on the Scanmar is hollow and has no
wood inside. That’s a good thing, as there is no wood to rot in there. |
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An acetal (plastic) Perko ¾”
through-hull was screwed onto the threaded end of the pipe. I mixed up some West
System thickened to a thick paste with colloidal silica and slobbered it on
the pipe threads, around the through hull, and the after end of the pipe to
eliminate leaks. Here you can also see where the installer has already
drilled & tapped a new hole where the new engine mount will be bolted. |
This is
the after side of the stringer showing the sealed drain. This drain works
beautifully, and ensures that any leaks under the engine will find its way to
the deep bilge. Incidentally, this won’t much since the next stringer forward
is solid; it must have a similar drain built into it so the water can pass
through the stringer into the deep bilge. |
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This is
a view from the engine pan looking forward. You can see that the next
stringer forward is solid and also has a couple of
silly, useless little holes punched through. |
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The
official Yanmar installation jig centered on the
engine bed, showing the position of the mounting feet. This jig is actually for
the 3GM30, but the mounting position of the feet is identical to the 3YM30.
The Scanmar’s engine bed is steel bar stock
embedded in a ¼” thickness of fiberglass.
The plan is to drill new holes and tap for machine bolts. You can see how the new bolt holes for the
stock engine mounting would be about ½” off center. I wasn’t too happy about
that, but Mickey the installer had a plan. He
proposed to lengthen each mounting foot by a half inch or so, since the
mounting profile of the Yanmar was narrower by ½”
on center than the Volvo. Another
possibility was to bolt timbers onto the bed, and then bolt the engine to the
timber using lag bolts. Instead we
decided to lengthen to feet slightly, allowing us to drill & tap new
holes in the steel of the existing bed. The alternative was to
bolt or fiberglass heavy, wide wooden stringers to the existing bed, and then
attach the engine mounts with lag bolts driven into the new wooden
stringers. I’ve been told that this is a common method. |
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I opted
for Mickey’s plan of lengthening the feet slightly. I was also uncomfortable
about this plan as well, but he assured me that he had “checked with Yanmar” and that they gave him their blessing.Here
you can see how a steel extension was welded onto the foot, the original bolt
hole was filled, and a new hole drilled for mounting bolts, offset from the
original one. He also told me that he
had done this many times. Again those bells were ringing in my head… |
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One of
the disadvantages of the 3YM30 is that it was not available with a down-angle
trans. The old Volvo-Penta’s trans had a slight
down-angle (about 5º) so that the engine could sit fairly level on the
bed. I couldn’t understand why Yanmar would sell the 3GM30 with a down-angle trans, but
did not sell its successor, the 3YM30, with such a trans. I asked Mickey to
check, but he swore that Yanmar told him that they
did not sell a down-angled trans with the 3YM engines. That
being the case, we had to raise the front of the engine and lower the rear to
obtain a straight shot for the prop shaft. Here you see teak shims that
Mickey had cut and placed under the forward foot of the engine. Once he
determined the correct location of the engine, Mickey marked the location for
the new bolts, and drilled into the bed. Incidentally,
the trans ratio which Mickey chose was the 2.62:1. In this at least, he was
probably correct since the old Volvo had a trans of 2.73:1 (I will check this, but I believe it is
correct). |
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Unfortunately,
we discovered that the embedded steel bar does not run the full length of the
bed. This hole we made in the bed just caught the forward edge of the steel; it
really would not be strong or reliable enough to hold a shaky engine. Mickey
the installer decided to use huge sheet metal screws or lag bolts screwed
into the non-reinforced fiberglass. This was the first major fight I had with
him. I was completely opposed to this idea it, as anyone knows how easily a
sheet metal screw can be pulled out of fiberglass. Believe it or not, Mickey fought me for days
on this issue, and seemingly would not budge. I was had just decided to fire
him when he relented, and decided instead to through-bolt the engine mounts
to the bed at the front of the stringers where the steel was missing. Below
you see a closeup of one of the engine bed’s
stringers with an access hole we cut out to allow the use of a nut to hold
the bolt. The narrower footprint of
the Yanmar is apparent here, as you can see how much
off-center the bolt is positioned. The
picture on the lower right shows the engine bolted to the bed on its shims. |
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The Yanmar bolted to the bed. Note the rectangular hole which
had to be cut into the bulkhead to accommodate the Yanma’s
tall exhaust riser. This photo shows the easy access to the oil dispstick, oil filler, secondary fuel filter, and raw
water pump at the left front side of the engine. Also, the raw water system
has a petcock which allows you to drain the engine of salt water for winter
storage; this petcock is visible in the “tee” fitting just below the
crankshaft pulley. Another
major disagreement I had with Mickey the installer was my idea of installing
a dual, parallel set of Racor primary fuel filters.
I wanted to build a panel on which two identical Racor
filters would be mounted, with a simple manifold which would allow you to
switch from a clogged filter to a clean, spare filter without stopping and
bleeding the engine. Mickey vehemently opposed this idea, and dismissed it as
a silly gimmick. When I say “opposed”, I don’t just mean that he said “I
don’t think it’s a good idea” and continued with his work; I mean that he
would argue with me over and over again, sometimes for hours at a stretch,
about how dumb my ideas were and how superior his were. More alarm bells went off in my head… |
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I am a business
owner too, just like Mickey the installer. Sometimes I have a client who
would ask me to do something that I
knew might cause him a problem, and I always felt it was my responsibility to
tell him why it might be a problem, and to urge him to abandon such a
course. But ultimately, the customer
is the one paying the bills, and if he insisted I would do as he asked with a
disclaimer that if his plan did indeed cause a problem,
that he should relieve me of any responsibility since I had advised
against the plan. Mickey didn’t see it
that way. In his eyes, there were three ways to do something: the Well,
here is another example of Mickey’s Way. The new Yanmar
exhaust is 2” in diameter, while the old Volvo’s was 1 ¾”. Now to me, it was
obvious that we had to replace the exhaust.
Mickey flatly refused to replace the exhaust, “guaranteeing” me that
the engine would not suffer from necking down the exhaust. I wouldn’t give in
on this point though. By chance, I
bumped into the Yanmar salesman who had sold me the
engine, and asked him whether we should keep the old smaller exhaust, or
replace with 2”. He said that he was sure that Yanmar
had gone to a 2” exhaust for a very good reason, and in fact we might void
the warranty if we did not use a
2” exhaust as specified by Yanmar. |
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This is
the new 2” exhaust which Mickey very reluctantly installed, after the Yanmar rep contacted him about it. Although
in the end I had the exhaust I had asked for, Mickey was furious that I had
mentioned it to the rep. I should
mention at this point that Mickey was a former Here is
the new water-lift muffler in the machinery space; it is from Vetus. A heavy nylon web strap secures it to the deck. |
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The Yanmar engine and trans is quite a bit shorter than the
Volvo. This meant that we needed a
longer propeller shaft. The original
shaft is 25mm in diameter, but that’s an odd size and required a special
order here in the You can
also see in this picture that the engine mount on the left is cocked to the
right; it is not parallel to the engine bed. Sloppy! Here is
a closeup of the DriveSaver.
It’s a very good thing to have one between the trans and prop shaft to act as
a sacrificial “circuit breaker” which will tear apart rather than ruin your
trans in case your prop hits something in the water, or becomes entangled in
a line. At $125, it’s cheap insurance. You can see that there is no metal-to-metal
contact between the shaft and the trans when you use a DriveSaver. The company literature states that the DriveSaver:
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As you
can see, even after the Drive Saver was installed, the rear of the prop (with
the “Prop Protector” blade installed) was only 1/8” from the strut, not
enough to allow water to flow through the cutless bearing
for proper lubrication. The new $600
prop shaft was far too short. The
prop rotation on the Yanmar is also the opposite of
the Volvo, so the old prop had to go. I opted for a 3-bladed prop, since I
don’t race and don’t mind trading a slight loss in sailing speed for more
power and efficiency when motoring, especially when backing. Here’s
a closeup of the Prop Protector. It’s a blade designed to slice through any line
if entangled around the prop. It does not indiscriminately cut any line it
encounters, but only if they wrap around the prop. The area I sail in has
hundreds of lobster pots, and in some places it’s nearly impossible to avoid
hitting at least one. A friend of mine nearly lost his boat when he caught
his prop on a lobster pot’s line, and the shaft pulled out of the boat. That’s a pretty big hole in the bottom of
your boat! The Prop Protector was
rated a “Best Buy” in Practical Sailor
magazine and is available in a one-piece blade (which requires that the prop
is pulled) and a split-blade, which is in two halves so it can be attached
without removing the prop. The price, by the way, is very reasonable.
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I took
the opportunity to install a dripless stuffing box.
I chose the PSS Dripless
seal, which seemed to have the fewest problems. The barbed fitting is to
feed water into the bearing, and was attached to the sea water intake. But
not by Mickey, who of course felt this was not necessary; I eventually hired
another mechanic to correct all of Mickey’s mistakes. This brand of dripless stuffing box is essentially maintenance-free. The PSS Shaft Seal is a mechanical seal that uses a self-aligning
carbon-graphite stator to ensure a 100% watertight seal with proven
reliability. This seal will eliminate shaft wear and minimize corrosion. I am now dreaming of a dry bilge!
The large,
transparent reinforced hose you see on the right runs from the bilge to the
manual bilge pump. I believe this is
the original installation, but it is in a ridiculous location. I have
been told by another sailor who installed a 3YM30 that the engine requires a
¾” seawater intake to properly cool this engine. If yours is ½”, you will
need to upgrade this. |
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The Yanmar “B” control panel is almost exactly the same size
as the Volvo’s, and fits quite well in the hole left from the old panel. It
has a tach and digital hour meter, and a series of
idiot lights. The smaller Volvo panel,
which held the fuel gauge, was removed because it was wired into the engine
panel’s circuitry; it was also a good time to install a new sender in the
fuel tank. Yanmar
sells a larger panel with more bells & whistles, but I think that this is
all one really needs. Also, there would then be no room for a fuel
gauge. The T-handle stop control was
removed, as it now served no purpose; the Yanmar
has a button on the control panel to shut down the engine. Because
I liked the Volvo single-lever throttle and shift control, I decided to keep
it if possible. While the throttle
cable was long enough to reach the engine, the Volvo had this cable running
to the upper starboard side of the engine, but the Yanmar
needed it to be on the lower port side.
Since it was a bit too short to, it was necessary to replace the
throttle cable with a longer one. The shift cable fit well and needed no
modification. |
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Since I
had to make up a small panel to replace the Volvo’s fuel gauge panel, I
decided to build my panel with a vacuum as well as a fuel gauge since I had
the room. Racor sells a rugged vacuum gauge which
is placed on the outlet side of the primary fuel filter. As long as the
needle on the gauge stays in the white, the filter is clean. When it hits the
yellow area, it is time to change the filter element. I have had too many filters clog with no
warning other than the engine stalling. Using
the old Volvo fuel gauge panel as a template, I made up a panel from black Lexan to hold the new fuel gauge and the vacuum gauge. |
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This is
the rear of the new panel. I installed a bronze ¼” NPT elbow directly onto the
gauge, and threaded in a ¼” NPT – 5/16” hose barb to accommodate a 5/16”
heavy-walled fuel line. This fuel line
cannot be more than 10’ long, or the hose may collapse; but the hose worked
out to be only about 5-6’ long, This hose leads to a bronze tee on the outlet
side of the fuel filter manifold which will be mounted in the engine room. The
upper gauge (on the left here since the panel is on its side) is a Tempo fuel
gauge. I also installed a matching
Tempo sending unit in the fuel tank, but the gauge seems to be reading much
lower than the actual level of fuel in the tank. Since the fuel gauge works
on a small current, it’s possible that the wires I used were |
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too thin- I will be checking that out.
It’s necessary to tap into the Yanmar’s
ignition switch to supply 12v + for the fuel gauge. Another mistake I made was to make the
wires leading to the Yanmar panel too short- just long enough, but they should be longer so that I can
maneuver the panels more easily. Below
is the (nearly) finished panel installation.
The Yanmar panel has a thick rubber gasket
to “waterproof” it, but I found that after only a few weeks in the salt air,
the panel’s brass electrical nuts & bolts were covered with a nice layer
of green corrosion. And this was while
the boat was on the hard! The installer (the magnificent Mickey) failed to
coat all electrical connections with dielectric grease as he should. |
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To seal
the fuel/vacuum gauge panel against water intrusion, I used a goodly amount of
silicone behind it. The original plexiglass shield will also be replaced to further help
keep everything dry. The fuel gauge is illuminated; the light is on whenever
the ignition is on. Here is
the finished fuel/vacuum gauge panel installed in the cockpit alongside the
stock Yanmar panel. I think it looks pretty darn
good, and in addition I can easily monitor the state of my active fuel filter
at a glance. |
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I felt
that the original plexiglass shield Scanmar had installed was a good idea, but I didn’t like
the silicone which they slopped-on under the top & sides to seal out the
rain & splashing water. I had some
Bomar “Hatch Tape” left over from mounting the
replacement hatch in the salon. This tape is much better than any caulk for
mounting a port or hatch- it produces a neater installation and will not
leak. It is a neoprene-like rubber which is impregnated with adhesive; it is
a like a cross between a rubber gasket and putty. The cross-hatching you see on the gasket is
a thin netting which helps the tape keep it shape
until it is applied & compressed. The
hole below the fuel gauge panel is from the old stop T-handle; I will
probably fill it temporarily since it is a handy place to mount a waterproof
toggle switch. Don’t know what the switch will be for, I am sure though that
I’ll find a use for one! |
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So now,
the engine was installed; but was it really
done? First off, the prop shaft
was too short, right? Well, not according to Mickey! He felt it was just right as it was. But marine
architects and vendors say that you need at least ¾” between the prop and
rear edge of the cutless bearing to allow the free
flow of water through the grooves in the rubber lining of the bearing. Mickey
would not correct this problem.
Secondly, the engine was obviously misaligned. To my eye, the engine
was not parallel to the lines off the boat. I asked Mickey several times to
re-check the alignment, but he said it was not necessary as it was fine. Now
I’m not an engine installer, but I do know something about this. There are two types of alignment, “offset”
and “angular”. |
Offset Alignment |
Angular Alignment |
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Judging
by the way the engine looked to my untrained eye, the
angular alignment was way off. The mechanic is supposed to perform the final
dry alignment on an engine by unbolting the trans coupling from the propeller
shaft, separating the two flange halves by the thickness of a sheet of paper,
and turning the prop shaft by hand. If the engine is properly aligned, the
trans flange should be perfectly parallel to the prop flange, and they should
not touch anywhere when the prop shaft is rotated. The tolerance for misalignment is generally
understood to be .005”, but Yanmar specifies .003”. The
problem with my installation was that because the prop shaft was cut too
short, the two flange halves were 1” apart once the DriveSaver
was removed. It was impossible to check if the two coupling flanges with a
feeler gauge, which meant that it was impossible
to align the engine! Mickey said that because we used a flexible
coupling (the DriveSaver), we did not need to align
the engine and shaft. This was a load of bull, as the main purpose of the DriveSaver is to act as a “circuit breaker” and break if
the prop meets with a restriction. It does help to dampen vibration slightly
and helps smooth out slight changes
in alignment under power. Another
issue I had with Mickey was that he absolutely refused to perform a “wet
alignment” after launching. The fact is, because a boat’s hull is flexible,
the alignment will very likely change somewhat after the boat is launched and
allowed to settle for several days. Mickey stated that he was done, and never
heard of re-aligning the engine after launching. I found
this on a marine engineering website: “The most critical
part of an engine replacement is the new engine alignment with the prop
shaft. The tolerance on this is .004" maximum. This measurement is taken
between the engine flange and the shaft flange. It is in two planes, vertical
and horizontal. It is crucial to get this alignment as close as possible to
eliminate vibration and wear. Also, since the new diesel is mounted on
flexible mounts, this angle will change when the engine is placed under load
and the shaft exerts forward force on the engine while in gear and pushes the
engine forward thus changing the angle. To compensate for this, a good
quality flexible coupling should be used between the engine and shaft
flanges.” |
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Once I
was rid of Mickey, I had to hire a competent mechanic to check the engine
alignment which I felt was out, and to “lengthen” the shaft if possible. I
asked around the boatyard, and heard that Doug Stout of “Marine Engine
Services” of 1. The angular alignment of engine
and shaft was way off, at least by .125” (1/8”); that’s more than forty times the maximum tolerance (.003”) allowed
by Yanmar! 2. The offset alignment was also off
a lot, such that the front of the engine drooped downwards and would need to
be raised to get the axis of the engine to be in line and parallel with the
shaft. 3. Another problem which I wasn’t aware
of was that the front engine mounts were cranked up to the max (the limit of
the bolts), and the rear ones were tightened down to a metal-to-metal
contact. In other words, the rubber in the mounts were not being used at all,
but rather were compressed downwards to the limit of their movement until the
upper bracket of the mount contacted the lower bracket. Might as well not
even have a rubber engine mount there!
4. The propeller shaft was far too
short. 5. The exhaust was improperly
installed, such that water could enter the engine through the exhaust port. |
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Yanmar specifies that the exhaust riser on the engine must rise
at least 12” (I believe that’s the measurement) above the waterline of the
boat. Mickey had used only the stock exhaust riser, and so we had only about
4” of height above the waterline. Doug
proposed raising the exhaust riser to help prevent the backflow of water into
the engine through the exhaust. Doug’s solution to the too-low exhaust riser
problem was to add a galvanized nipple and coupling between the engine and
riser itself. Here’s
a great article on the subject, if you are technically inclined: http://www.boatus.com/goodoldboat/Marine_exhaust.htm To the
left is the extended exhaust riser which Doug built for me. |
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Doug
removed the engine from the useless stock Yanmar
mounts, and replaced them with Globe (?) mounts. Doug said that these
aftermarket mounts are very robust and have a greater range of adjustment. He was able to move the engine aft about
2-1/2”, which in turn gave us about 2-3/4” of space between the strut and
Prop Protector. Here’s a photo of the
prop and strut after the engine was moved into its proper position. Compare this photo with the one above! |
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To be continued… |
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