Generator, Buy Or Build?

While trying to decide which generator to buy for power outages I ran across a posting in a
survival/preparedness forum that had a link to a website about building your own generator.
After reading the information I decided I had to build a home-built generator for myself.
I decided to build one using a verticle shaft engine. These are plentyful and very cheap. If I ever
need to replace the engine I'll have tons to choose from. One of these will be great for Field Day
(Ham Radio) in June too.

I posted a request for a cheap lawn mower engine on my company's "For Sale" website and got
an offer for a free 5.5HP Honda engine, and several offers for 3.5-6.5HP engines for $25, and several unknown brands
and HP for free within a few hours.
I picked up a free 4HP Tecumseh engine. I chose this one as it was immediately available and was on my way home from work.
It needed a cleaning, tune-up, and oil change, but I would normally do that with a used engine anyways. It now starts up easily.

Parts List and exploded View                               Operator Manual

Engine / Alternator Bracket
It was suggested that I use Epicenter's drawing as a pattern, but for $25 I'd rather just buy one ready-made.
If they wanted $125 I might consider making my own. The brackets from Epicenter are 1/8" steel and are well made.


I researched the alternators that Epicenter recommends and sells.
I've created a chart with Epicenter, O'Reilly's, and AutoZone parts numbers and prices. Prices were
figured using my zip code so your prices many vary. Also shipping and state sales tax may change
your savings.

Epicenter Part Number Epicenter Cost Delco Series Amp Part Number, $Cost (Core) Warranty
7127 $59 10SI 63AO'Reilly's 01-0039X, $22 ($6) 1 yr
O'Reilly's 01-0039, $40 (10) lifetime
AutoZone 7127, $23 (15) 1 yr
AutoZone DL7172M, $40 (15) lifetime
7273 $79 12SI 78A O'Reilly's 01-0249, $70 (25) lifetime
AutoZone 7273, $66 (30) 1 yr
AutoZone DL7273, $81 (30) Lifetime
7294 $99 12SI 94A O'Reilly's 01-0269, $90 (25) lifetime
O'Reilly's 01-0244 $75 (25) lifetime
AutoZone 7294, $53 (30) 1 yr
AutoZone DL7294, $71 (30) lifetime
The 7127 is $31 cheaper from O'Reilly's.
The 7273 is cheaper from Epicenter.
The 7294 is $16 cheaper from AutoZone.
Another consideration is I think I'd rather be able to return the alternator locally in case
of failure.
I picked up an O'Reilly's 01-0039X locally for $30.30.(includes TX sales tax)
Make sure you get a wiring plug for the alternator. Epicenter has them for $5.

Sheave and Belt

Epicenter has the sheave for $14 and belt for $9.
Grainger has the sheave (3x768) for $11.49 and the belt (4L300H) for $4.10.

Putting It All Together
So far I've gone through my engine and have it running. I decided to use a Champion RJ19LM spark plug because it has a resistor. I plan on occasionally running Ham equipment from the generator and want to reduce as much electrical noise as possible.
I picked up 2 RJ19LMs locally from Northern Tool and Equipment for $4.

I decided at least for now to tie wrap the brake lever in the "Run" position until I work out another way of controlling the running of the engine. Basically for now you have to cut the tie wrap to kill the engine. My plan is to add a fuel cutoff switch between the fuel tank and the carburetor.

Getting the blade off the engine was simple using an impact wrench.

Getting the shaft coupler (what the blade mounts to) off the crankshaft was VERY difficult. I broke the crappy $8 gear puller I bought from O'Reilly's and even had a hard time with the better made $9 gear puller from Northern Tool and my impact wrench. I have to rethink using surplus spare motors after the SHTF. This is not something you want to do by hand! If you don't have an impact wrench, you will need to find someone who is willing to pull this off for you. I might try picking up a spare motor so I can have the coupler already off before I need the engine.

Next step is to build the base. I have several ideas for wheeled bases, but built a basic 2x4 base first.

Building the base

Bottom view -fully enclosed for safety --After this picture was taken I added some fender washers to the engine bolts.

I've been thinking about eventually using one of these:
instead of the temporary wooden base. I think that the size is perfect where I can weld the ends. Since there will be a 1/2" gap lengthwise I think some small angle iron will allow welding lengthwise. The only problem is cost. Even though the base is only $33, it would be the most expensive item in the project.

Ready to wire 'er up.

Wiring is simple. For my alternator I used the diagram below:

I wired my alternator to a small deep cycle battery bank, so I still have power even when the generator is not running. I use a 75amp Anderson PowerPole to connect to the battery bank. The ON-OFF switch allows easier starting of the engine with no load.

On the to-do list is to paint the bracket. I may wait until I have the final base to paint it, although I'll probably spray some primer on it soon to prevent rust in the meantime.

Engine Free
Vertical Shaft mounting bracket $24.95
Wiring plug for new style GM alternator $5.00
A style V belt, for vertical shaft $9.00
Sheave for vertical shaft. 2.5x7/8 $14.00
Alternator $30.30
2 Spark Plugs $3.98
2 quarts SAE 30 oil $4.24
Air filter $3.98
Gear Puller from Northern Tool $8.99
4 feet of 2x4, bolts, washers, wire,
connectors, split loom, ON-OFF bracket
Already owned
SPST switch(ON-OFF)$2.09
Shipping costs $12.61