My Small Engine Projects

To get the alternator to turn on, you need an external power source, like a battery to charge the field so it can magnetize. But once you get the alternator to turn on then you don't need the battery any more. A generator is different because a generator has permanent magnets in it and doesn't need an external power source to turn on, just need to spin it.

@prancstaman good point!

Once it is running there is lot of 12 volts lights and motors you can run with it. Junk yards are full of 12 volt fan motors and lights.

Thanks Prancstaman, I hadn't thought of that. The only reason I'd be using an alternator is because they're easier/cheaper to get hold of. So if I was using an alternator I could have the alternator charging a battery and the lights or whatever running off the battery?

Yes sir. Just like an automotive style electrical system.

Sounds good. I just need to find a cheap alternator now. And I'm just wondering if it matters what way the alternator turns? I'm assuming it works just one way but I'm not sure. 

Here's the pics of the governor linkage. When I got the engine there was just a spring holding the throttle to idle. So I found a governor flap and bent up a linkage. I may need to lossen the spring because it has a little too much tension but overall it's pretty good.


In this pic you can just about see the governor flap, the other end of the linkage connects to it. The governor works just like the 3.5hp Briggs engines. I also need to weld up the throttle lever as it is cracked.


She's running really well at the moment, I may have to clean the carb out properly some time but for now it's grand. As I've been running her I've noticed the compression getting better and she burns very little oil (which is always a bonus with these little engines). I do need to sort out a proper way to stop the engine because at the moment I'm just putting a hand over the air intake. The sparkplug lead should have a bare metal end on it to allow you to ground the spark but for some reason this has been replaced. I think I have one laying around so I'll have to find it and put it on.

I like to have my engines with the original fittings and things so I swapped the shroud and tank back to the one that came on this engine. This engine is a newer type (25a), the shroud with the tank on it is from an older type 21a Suffolk. I plan on getting my other suffolk running so the shroud/tank setup needs to go back to it.
I need to make a bracket to hold the tank and I'm cleaning the rust out of the tank with caustic soda and water.



I found this bench grinder with a bad electric motor and I think it would be cool to power it with the Suffolk. I'll take it apart and see how easily I can remove the electric motor and put a pulley on one end and run a belt to the engine.

I think the motor output shaft is the same shaft all the way through to both wheels. Might need to get creative with mounting and pulleys but definitely possible. It would be pretty neat

Yeah I did think that. I think it's a 3/4" shaft as well. I'll see how it all works when I take it apart.

i’ve seen a couple of bench grinders with the motors ripped out, the housing cut out for a belt and a pulley installed. this is a great idea for something to power with your motor.

Yeah I was thinking of removing the wire brush and putting the pulley on that side. I'm hoping I can take the electric motor out but reinstall the shaft. I think I may have to go back to the shroud type tank because the other tank is really badly rusted and I'm having a hard time getting all the rust out. I also lost the tank cap into some long grass.

While browsing the 'net, I found this Suffolk and dynamo set on ebay. This is sorta the thing I'm going for:
https://www.ebay.co.uk/itm/vintage-stationary-engine-vintage-generator/132618619700?hash=item1ee0af8b34

If you're going to take it to shows, maybe you would want to put a couple of wheels and a handle on it to move it around easily.

How much voltage/amps would it produce?  I need a generator too, might borrow your idea.

Crazy_Carl wrote:

If you're going to take it to shows, maybe you would want to put a couple of wheels and a handle on it to move it around easily.

Yeah I was thinking of putting some push mower wheels or casters on it.

Double W Cross Ranch wrote:

How much voltage/amps would it produce?  I need a generator too, might borrow your idea.

Depends on the alternator/generator you're using I suppose. A portable generator is handy.

So I found some time to take this grinder apart. I can't seem to get the sides off the housing, the bearing seems stuck on the shaft. On the upside though, the shaft goes all the way though with bearings either side so I could easily put a pulley on one side and drive it that way.

I'd wack the endbells of the motor with a soft mallet or better yet a lead hammer and try to knock them loose.  I wonder if you could put a pulley right next to the grinding stone and still have the wire brush on the other side.  That would be really handy.

Yeah I'll try that. There might be room for a pulley beside the grinding stone, I'll see if I have a thin pulley.

Nothing more to update on the grinder, haven't got round to looking at that again. I have tried to clear the rust out of the tank, but it seems to be too badly rusted up. I've also lost the cap and can't find it so I'm going to have to use another tank or make one.

Try Coca cola to clean the gas tank. Old school trick. Buy a bottle, dump it in, and wait about a half hour to check on it.

An alternator will work spinning either way (bidirectional, all of them)because it is producing alternating current and runs through a rectifier to turn alternating current into direct current, just have to worry about the fan blades on the front which only cool efficiently spinning the correct way. If your lucky, the alternator you choose will have the blades going straight out from the center shaft which will work efficiently spinning both ways for the cooling. You will also need an external power source to turn on the alternator because an alternator when it makes electricity uses electro magnets, not a permanent magnet like an old generator.

As for generators, the really old ones had permanent magnets in them and don't need an external power source to work, you just have to spin them. The newer generators like the one in the pic, a few posts above, you need an external power source for it to work because just like the alternator has electro magnets instead of permanent magnets. Plus a generator, no matter how old, is directional sensitive, meaning that you have to spin it in a certain direction for it to produce power out of the positive post. If you spin it backwards, then the case will be positively charged and the output post will be negatively charged (very bad if not a positive ground system). This is because the armature is made like a starter armature with what you call a computator (the part the brushes ride on) separate the positive and negative power when produced.

As for the external power source, doesn't really need to be that big, just strong enough to turn on the alternator or generator (for the electro magnets), then the voltage regulator will keep it making power for the load.

And it takes 1 hp to produce 27 amps. This will help when choosing an alternator or generator. Don't want to be using it and put a load on it to where the motor stops because the motor isn't strong enough to turn it.

Nice idea, I made me one for jump starting cars. has a 6 hp motor with about a 60 amp alternator I think on it. I have a spot for a car battery but usually don't need it because when I hook it up to the car I'm jump starting, even though the battery isn't strong enough to start the car it will turn on the alternator to charge the battery, and when the battery is fully charged it will start the car. The setup I have will only charge the battery to full charge and not start the car on it's own because it is only about 60 amps. Just to give you an idea on how to use it. I also have the option of hooking the battery up and running a power inverter for 110v house power to run a small drill if I really needed to, for another idea but not really efficient using it that way.

One more thing. Hooking an alternator or generator up to an engine, you need a governor that works really good so you don't over rev the engine when the alternator or generator is switching from a loaded condition to a non loaded condition. Say you have the motor full throttle charging a battery and the battery is then fully charged and the regulator turns off the charging. Since the motor is full throttle coming off the load will over rev if there isn't a governor to stop it. Just something to think about.

It's a metal tank right? I have used vinegar before and it worked but I am curious to try pool cleaner. It is quite toxic and I don't know how I would dispose of it but apparently it cleans the rust off in less than 10 minutes. I have a pressure washer with a rusty tank right now.

Thanks for the info Prancstaman! I have heard of using coca cola to free up seized engines. I will try that with the tank. 

Yeah I will use a battery as an external power source to turn on the alternator. I have got 2 of these little Suffolks so I could have one running the alternator and the other running the bench grinder. I'l most likely be using an alternator, because they are easier/cheaper to get hold of compared to the old belt driven style generators.

I think the 75cc Suffolk that I have is rated for 1hp @3000ish rpm so I would have to get an alternator that produces around 27-30 amps.

Yeah the governor linkages were all missing when I got this engine so I had to make my own, and as I said earlier the spring is a little too tight so the engine revs quite high without much movement of the throttle lever. I do plan on adjusting that when I get a chance.

muckmudd wrote:

It's a metal tank right? I have used vinegar before and it worked but I am curious to try pool cleaner. It is quite toxic and I don't know how I would dispose of it but apparently it cleans the rust off in less than 10 minutes. I have a pressure washer with a rusty tank right now.

Yeah it's metal. There's a photo of it a few posts up. I didn't think vinegar was strong enough to clear rust, I do use it in carbs and it works well. I'll probably not use this tank unless I can find the cap, which seems to have disappeared

So a little change of plan. I think the Suffolk would probably struggle to run an alternator which produced decent current. So I have this Honda G300 in the shed, 7hp @3600. It is a flathead, the predecessor of the famous GX range. I think it's been in a fire at some point, the right of the shroud has gone black and the fan on the flywheel was melted. This was my first small engine I got, so I've had it a while. I remember it never used to run with the choke off, I seem to remember the head was cracked. I'll have to take it apart and see. Using this engine means I will be able to run a bigger alternator. By my calculations this engine can run a 189 amp alternator. I haven't had it running in a while, the carb is off it which I will have to clean. There is still a bit of fuel in it, smells like paint or something  I do have a recoil for it but the spring is gone so I'll just pull it with a starter rope.



I think the shaft is 1", not sure. 

looks like it’s in pretty rough shape but that would be cool to get it running.

It's not too bad, just the paint on the shroud is damaged. It's pretty dusty, so I'll have to wash it, should look better after that.

It is pretty dirty! A good cleaning up and fresh paint on the shroud would look like new. What about the melted fan?