1. All the tools and spare parts you will need to replace a propeller.
2. Replacements for all fuses on board
3. Replacements for all lightbulbs on board
4. Tie wraps and duct tape
5. Phillips and slotted screwdrivers
6. Adjustable wrench
7. Emory paper/sand paper

 

Spare IAC
Spare water/fuel separator
Spare serpentine belt
Rescue tape
and this:
https://www.westmarine.com/buy/west-marine--shipyard-tool-kit--11147691?recordNum=1

 

I have learned that a preventative maintenance routine means I rarely need my tools or spares, although I carry them. Over many years of boating, the ones I have needed are the prop replacement kit, the fuel filter replacement kit, and a wiring fix kit. I have never needed my wrenches or screwdrivers, fuses or bulbs (since LED's). I find a good flashlight is invaluable.

 

First off, I'm a firm believer in quality tools, especially if you are using them on a regular basis.

That said for occasional boat tasks that pop up, this is what I do.

Tools Needed
For general maintenance issues on a boat, a decent socket set, wrench set, plier set, a multi-meter, wire strippers/crimpers, and some screw drivers from Harbor Freight should cover most tasks. A cordless drill with actual drill bits, screwdriver bits, and SAE/Metric nutdrivers is quite handy.

Spare Parts
Keep onhand an electronic connector set, heat shrink tubing, stainless steel assortment of nuts, bolts, and wood screws. Some plastic plumbing fittings, tubing, Pex connectors, and stainless hose clamps would be good to have as well. Add in rolls of duct tape, rescue tape, and electrical tape.

Belts, filters, and other wearable items would nice to have.

Finally, a hammer and a bottle of vodka for stupid projects stealing your time.

 

I store a good craftsman set of sockets on board ( 100 pc ) Then a bag full of harbour freight tools. Nothing like dropping a $10 wrench in the water rather then a $2 wrench. HF has good quality tools for what you need at a reasonable price. Also a must is zip ties, duck tape, and a extender magnet pole for all those parts or tools that fall just a inch out of your reach under the motor.
Also keep a ton of spair parts, belts, filters, bulbs, fuses ect.

 

Multi meter
Tape measure
Electrical tape, painters tape
Usual screwdrivers, sockets
I use a harbor freight tool bag that fits neatly in the bottom of my closet in the state room..... easy access and out of the way

 

Adding to what’s here. An extension thing with a small mirror may help when you need to figure out what’s behind something. I also take photos around the corner with the phone. Also a rubber mallet. Something like a starter with a little rust in it sometimes needs a couple of hits until you can replace it. Also some small things of 3M sealant. I use the 1oz ones so I don’t have a dry tube next time I need one. Measuring tape!

 

I keep a similar tool kit on board. Most all of the same parts and pieces mentioned. Never have kept an IAC valve. Might need to. We are on a relatively small lake (440 miles of shoreline) so I am going to keep the majority on the dock now. I can easily limp back on one drive if need be.

 

Once we met an elderly couple with a converted 68 foot tug. I asked him what he carried for tools and spare parts. He showed me his cell phone.

 

Get a couple of those extendable grabber/magnet things to pick up anything you drop.

 

A bore scope camera and a heat lazer gun is also a great idea. Guages sometimes are off and get a better read with the lazer. Also a bore scope camera will help in looking at spots no human persan can ever get too unless you are from a circus.