Need engine for Inboard drive - DIY?

[mgriffin]

Either it works or it doesn't work! I understand what you are saying srimes, and I know the precision machining that has to be done to produce a "perfect engine". As for your your questions, I am not going to use ball bearings to help reduce friction or piston rings to seal the piston. An the check valve,this: http://www.inpressure.com/check-valv...ck_Valves.html I would estimate this to last 100 million strokes, or 92.59 days at 750 rpm. That is the best I can do without spending thousands of dollars of machine tools like a lathe. Take the spudgun, made of pvc and wrapped in tape. It launches a potato 600 feet. You can make it for 15-20 dollars, or you can spend 200-300 dollars on an airgun that can kill a squirrel. Or you can just spend the 15-20 dollars it takes to make the spudgun, that does the same job. You get the point? I don't want to spend 120 dollars on a 2 horse motor if I can build one that sounds better for $70. To add to that, everyone would be asking, "Where did you get that motor?" and I could say, "I hand built it." I wouldn't try to build a motor if I didn't know crap about them! I can't afford to make a 70 dollar mistake on a 300 dollar budget when I still have to build my boat. Please say yes or no, it will work, or it won't work. I will buy the piston and the cylinder sleeve first, so if I make a mistake it will only cost me 12 dollars instead of a 70 dollar mistake. The steam engine I bought has no ball bearings, and it runs better without piston rings, and it runs at 1000 rpm. It is about half the size of the motor I want to build.

[PAR]

Michael, your still focused on this building your own engine thing . . .

Please by all means, build you motor, so you can learn about balanced reciprocal masses, thrust offsets and the many other things you just don't want to listen to when others mention them.

Failure is the best teacher, go for it dude . . .

[mgriffin]

Listening to that makes me have doubts, but at the beginning of the tread I mention that I might buy one also.
http://cgi.ebay.com/ebaymotors/2-hp-...ehicleQ5fParts
O.K or I could still make a bastardized 2 stroke diesel out of this and still get credit for building part of it .
http://cgi.ebay.com/NEW-TECUMSEH-ENG...4.c0.m14.l1262

[PAR]

Don't avoid the process, we all have gone through it, so will you. Build your engine, spend three times on it compared to a manufactured unit, just to have it "toss a rod" after a couple of hours of operation. Oops, maybe a real pressurized lubrication system and bearings would have been a good idea after all . . . live and learn or get more education and not attempt these primitive efforts, before you know what's required.

[mgriffin]

OK, I get it PAR. Reality has knocked on my door and slapped me in the face. I am just going to get a small 2 stroke off a weed whacker and de-tune it and tweak the fuel inlet and put a larger flywheel on it. I need a reliable engine in case I am going upstream against a strong current, and knowing the average 25cc 2 stroke, well I wouldn't call it too reliable. My dad has a weed whacker, and whenever he starts it, it keeps dying, but SOMETIMES it will keep going. When it dies, I hope it will die again so he'll get tired of it finally and buy a new one and I can have the motor off of that one. The first thing I would do is put a larger flywheel on it so it will keep going instead of keep dying. My dad said it would be O.K if I got a motor off a broken mower or a hedge trimmer, but I'm in the middle of Las Vegas for God's Sake! 80% of people out here don't even have a yard, and if they do it is usually desert or overgrown scrub! And I am pretty much going mad waiting for us to move to a bigger house in a place that actually has trees, wildlife and water so I can build my boat already. I'm sure you don't want to hear of my miseries, but it seems everything is going south lately. Ask Apex, his daughters died in a car accident a few days ago and he can hardly get it together enough to answer one of my PM's...Only thing I can do is pray that things get better soon. The economy still sucks, and Obama isn't really helping, but I'm sure all of you know that, don't even mention this great depression is worse than the last one, which lasted ten years.

[mgriffin]

You know what? My idea for a diesel 2 stroke with "dieseling" ignition is not the first one. Don't believe me? go to this link:
http://en.wikipedia.org/wiki/Bourke_Engine

[mgriffin]

Sorry folks, but I found an inboard. You can say what you want, but I am going to use this for my inboard: http://cgi.ebay.com/ebaymotors/2-hp-...ehicleQ5fParts

[marshmat]

The single-cylinder B&S are solid, reliable, simple engines that last for decades. Build some good mounts for it, give it plenty of ventilation, and it should serve you well.

[apex1]

Yeah, solid and durable. Not like the toys you found earlier.

[Marco1]

When I was 15 I built a kayak out of a corrugated iron sheet. Flattened it shaped it. riveted and soldered it, covered with Hessian bags painted with oil paint and a brush. Built a rudder with pedals and strings, the seat, yet I bought the paddle.
You build your boat first, then think of the motor.
You could do in reverse. Find a motor and build your boat around it.
Since you live in the good USA your prices for second hand engines are very affordable. I suggest something ex agricultural. A water pump, a generator, anything stationary...and I suggest petrol not diesel, not that I don't favour slow revving diesels like Lister. If you are on a shoestring budget, you can not go past an old stationary petrol engine. Dirt cheap to fix too and so easy.
Try to look for a hit and miss, now those are real fun.

http://www.youtube.com/watch?v=oEHGeg5WYYE

There are several post on you tube about Homemade hit and miss engines,
http://www.youtube.com/watch?v=j7amgDalq4E
http://www.youtube.com/watch?v=9rpgzQlrXIg&NR=1
but unless you have access to some serious turning and foundry equipment, you will have to buy parts and end up paying more for an inferior result. It can be done as an exercise in "mosquito coast syndrome"* but I think that your efforts are deserving of a better cause.
You could always do some odd jobs and keep the cash and buy a decent engine for half the effort.
*From the movie Mosquito Coast.

[TollyWally]

"mosquito coast syndrome"
Splendid book in it's own fashion. Reminds me of a saying of my old man's " Poor men have poor ways."

[apex1]

Originally Posted by Marco1

Since you live in the good USA your prices for second hand engines are very affordable. I suggest something ex agricultural. A water pump, a generator, anything stationary...and I suggest petrol not diesel, not that I don't favour slow revving diesels like Lister. If you are on a shoestring budget, you can not go past an old stationary petrol engine. Dirt cheap to fix too and so easy.

It took us the past ten month to talk Mike out of the crap. Now that he has found a cheap and reliable engine, you pop up and talk him into the crap again. I´m not amused.

Richard

[CDK]

Originally Posted by mgriffin

I am on budget of 300 dollars, and after I build my small boat, I will have 200 dollars left.

If you really want to stick to the budget, consider this:

I got my first boat when I was about 7 years old. That was 60 years ago.
It was 14 inches long, all metal. There was a loop of thin copper tube soldered to the stern, both openings below the waterline.
At the turn the tube was bend upwards slightly so you could place a candle under it. The candle made the water boil and the expelled mixture of water and steam propelled the boat.
In fact it was the only mechanism I ever saw that could propel a vehicle without any moving parts at all.

[mgriffin]

Well folks, sorry again...I just now realized that the b&s is not fo sale anymore. NO MATTER! I have found a similar one, for about the same price!
http://www.smallenginewarehouse.com/...Stroke,%2034CC
And how stupid was I when I thought I should wait to buy the b&s on ebay?

[marshmat]

Careful there Michael. That's a 34 cc weed whacker engine- exactly what you said earlier you don't want. These are not the same animal as the 150 to 300 cc Briggs single-cylinder that you found earlier (and that, I think, would be a great engine for your projects- simple, reliable, easy to fix and tweak). Marco's point is well taken; good 1-cylinder engines are all over the place in water pumps, agricultural applications, etc. as well as go-karts and the like, so parts (or complete motors) are cheap and easy to find.