How to install an inboard motor. Repacking a Stuffing Box. All Details

If you are looking for instructions on how to install an inboard motor, this is for you. This is a very detailed video for the technically minded on every aspect of how I installed the inboard motor, repacked the stuffing boxes, and aligned the propeller shaft in Moonlight, a traditional sailing trailer boat. #installingastuffingbox #howtoinstallaninboardmotor #propellershaft

Many of my trips in Moonlight involve transiting the broad expanses of places like the Great Sandy Strait, so fo me an inboard is not a luxury but a necessity. When the wind fails as it often can in this region, the currents are too strong to negotiate under oars, and the distances are too great.

The existing installation has served me well over the life of the boat, but recently the motor has been getting very noisy, and the shaft has started whipping around in a very disturbing manner. It wasn’t until I started probing around, that I realised just how bad the problem was.

If you look closely you can see the pillow block has detached itself from the keelson, so it is not providing any support for the shaft. So with the Christmas break coming on, there was a perfect window of time to steel myself to the task and get the project underway.

I couldn’t bring myself to dispose of this old piece of Huon Pine, so I used a lot of epoxy to rebuild it.

I’m using a Dulux Metalshield pressure pack for convenience. Normally you struggle to get the needed build with spray packs, but this product is an exception. No primer required, and it dries tough but still flexible. It is an experiment, and time will tell if I made the right call.

The motor was clattering a bit, and quite noisy, so I needed to check the valve clearances. While I was at it I recapped the spark plug. Turns out the tolerances were all correct to the manufacturer’s specs after a lifetime of use which says a lot for Honda engineering. This design is as old as the boat, Honda has not changed it much in 40 years.

The Coupling consists of two cast iron flanges and a rubber “spider” element, which performs well under compression and flexing. The modular design allows for a simple fitting and easy maintenance and the rubber element absorbs shock loading and compensates for any minor misalignment of the shaft.

For some reason, the bolt holes in the engine bed no longer line up with the engine mounting holes. I made up a template and bored slightly oversized holes to allow for aligning the shafts. I was surprised at how much things had moved around over time.

The bearing fits into the housing by twisting it into place.

Oil impregnated jute packing for the ⅝” stuffing boxes is still the same as it has been for 100’s of years, and it is easily acquired from any decent marine store. Once it is packed in there, the stuffing box can be reassembled and tightened just past finger tight. Don’t overdo the tightening as I did the first time around, creating a build-up of heat. It just needs to be packed tight enough to stop any major leaks. A drip or two is a sign you have it right, providing some cooling for the bearing. In this installation, there is no stern-tube, but the shaft hole is packed full of grease.

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00:00 Intro
2:30 Flexible coupling
4:30 The Thrust Bearing
6:30 The Pillow block
16:30 Packing the Stuffing Box
26:00 Watch how she runs

Copyright 2021 Vinsek Pty Ltd

[Makermook]

This video is a godsend. I built my oldest boy a boat which he uses to fish skinny water, tidal estuaries on the Atlantic coast. It has a thai longtail motor. I want to build my middle son a similar boat with an inboard motor, but until I watched this video, I had little idea how to put the shaft through the hull. Thank you!

[PaulChamberlain-ofdm]

Superb video, love the engine sound and talk through.Really great.

[daleskidmore]

Nice and easy to follow demo. Every step well thought out. It is funny how holes seem to move over the years, I've noticed it myself. The difference in before and after is great. It isn't easy to notice gradual changes until something bad happens usually. I like it when people adapt and repurpose one thing to do another: proper men in sheds engineering. Keep well.

[gregsaunders]

Dads! Can’t live with them or do without them.
My dad was a gifted tradesman but in the pursuit of success left the hands on practice of his craft to others. Shame really.
But it’s through him I get my interest in creating and fixing. Spent many hours rebuilding engines in boats, cars, and motorbikes with him. He too had difficulty in sharing his feelings without getting cranky.
Still, I am who I am because of his love and care. Didn’t spend enough time with him.

[koalajs]

I have learnt a lot by watching your video. Thank you

[carlchambers]

Really well done! I enjoyed watching this, and learned a few things. 👍

[classiccoffeecab]

Hi .. I am following your work and using your knowledge to help me do a similar engine fit on my clinker. Is there any reason you don't use a Centrifugal Clutch on the honda. And to reduce vibration, fit a rubber engine mount.

[AnthonyZucca]

Great video, thanks! Have you considered adding a spark arrestor to the air box?

[Makermook]

I'm trying to build a similar inboard propulsion system on my boat. If you don't mind my asking, how large is the hole in the stern log through which the prop shaft passes? It looks considerably larger than the 5/8" shaft itself. And did you say you packed that entire space with grease? Thanks.

[brucebehnfeldt]

what bearing is that? i've not seen a thrust bearing in a pillow block. thanks.