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Engine Mounts

More accurately, this page is about mounting the engine.

(1) I removed the original two engine mount brackets cut and welded in a piece of angle iron that will receive the new motor mounts and I build some new brackets for the rear of the motor where the fly wheel housing was once used to support the engine.

(1) Test fitting modified brackets
for new engine mounts.

(2) Lowing the engine in for










(2) The engine is out of the shop and hanging from a 13 foot high A frame now. I have some details about the A-Frame on the "Gantry" page. Having the A-Frame has been a real plus. Not trusting my measurements it is great to be able to hang the engine in place.

(3) 300 lb engine mount from

(4) Engine bed. Blind nuts on a
plate were welded into a tube
for the rear engine mounts.

(5) Blind nuts built into the
front of the engine bed for the
engine mount's bolts.

(6) Center frame completed with
a dip for the oil plan and the
engine beds bolted in.

(7) Much later when the lower
half of the engine compartment
was completed; an additional
frame was added to connect the
left and right engine beds

(8) Engine mount installed.

(9) Looking down into the hull
with the engine installed and the
drive shaft connecting it to the
speed up box.

(3) I purchased the motor mounts from The 4 mounts I ordered are $25 each, part number MD1422 and they are designed for 300lb. The body of the mount is aluminum with a rubber shock absorber that supports the mounting bolt.

(4) The engine bed supports are built from 2 inch square tubing with a 1/8 inch wall. Most of the engines' weight is on the taller forward supports built from 3 vertical tubes welded together.

(4) (5) Blind nuts are nuts that are fastened in place so it is not necessary to reach them with a wrench will tightening down a bolt. If it were a steel boat then I could simply weld the nuts in place, but it is not possible to weld stainless steel to aluminum or at least I can't. But this trick works. Find a piece of aluminum pipe that is too small on the inside for the nut to fit. Then cut a short piece of the pipe off and use a hammer to persuade it to go over the nut. In this case a 3/4 inch pipe is hammered over 1/2 inch nuts. Finally put the bolt in place to temporarily hold the pipe and nut and weld the pipe to the back of the plate. Smaller nuts can be hammered into holes drilled in 3/16 inch aluminum sheets and then the sheet can be tack welded into place.

(6) The center framing above the keel is completed now. There is a dip in it to accommodate the oil pan on the engine. It is welded solid as it will allow water to flow under the engine compartment. A small plate was installed just forward of the jet drive intake that will allow water to flowing through the center framing be diverted around the pump intake so there will be no trap that would only snag bilge trash.

(6) The engine bed is then bolted to a pair of longitudinals that are welded to the bottom of the hull.  (7) This photo was taken much later when the lower half of the engine compartment was completed and a frame was added to connect the left and right engine beds in order to eliminate any sideways flexing.

(8) (9) With the engine resting on the engine mounts, the nuts and be adjusted to change the height and angle of the engine. The jet pump drive staff has a 3 degree upward angle as it enters the boat. That angle is transferred to the shafts in the gear box and on toward the engine. The short dive shaft with dual u-joints between the gear box and engine can accommodate a change in the angel, but matching the engine to the same 3 degree angle reduces the work on the drive shaft and allows the engine to tork further to the sides if needed without damaging the joint. The engine bed was installed so that about 3/4 of an inch of drive splined shaft remained exposed where the u-joint slips over the splines. This will allow the shaft to slip back and forth without as needed without hitting the bottom.