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BF10 - BF30: What does it look like?

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looking4answers

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Ok, so I know these are Marine engines and such, but how similar are they to the Honda GX360K1? I know quite a bit about the GX360 as I've been diggin dirt up on it for a few years now, and since my uncle recently brought a Honda HT4814 home.

The BF8-BF20 are all 2 cylinder, OHC like the GX360.
The BF25-BF60 are all 3 cylinder, OHC. GX360 with additional cylinder?
Of course displacement chnages as needed, but the overall engine design is the same, correct?

I know Honda doesn't make the GX360 specifically, but I can't help to notice the sound of the BF10 being the exact same as the GX360.
Are the BF25-BF60 based off of the E07a engines fromt he kei cars over in Japan? IE Honda Beat?

So I ask. Has anyone ever removed one of these engines (BF8-BF60) from the boat motor housing/ case? Do you have pictures? If you do, can you post them?


I ask because I'm working on a project to revive my Gokart, but I want something to replace my Tecumseh with, and being a strict Honda/ Acura fan boy, I'm looking no further then a smallish, 300-800cc, OHC 2-3 Cylinder Inline engine. These fit the job. While the GX360 is my best and easiest choice(already being made for LAND use and not needing much work done to it) I'm also considering any of the 2 or 3 cylinder BF Marine engines, since they come more powerful, cleaner in Head design and revv higher from factory then the GX360.

I would greatly appreciate if someone could send me to the right place, so to speak, with pictures of the engine alone. Maybe a rebuild thread or a conversion?

I realize these engines don't come cheap new, but that given I'm determined enough, doesn't matter if I can find one used for a lower price and if I am happy with the application possibilities.

I really do love these automotive style OHC inline engines, and wish to cleanly set one up on a larger gokart, so ALL of the held I can get would be nice and greatly appreciated!

Again, if you have pictures of the engine or the casing removed exposing the engine, post them here. Same goes if you have links to a thread with said information.

Thank you!:eek:
 
Hi, you sound like a pleasant and sincere person so I want to start out by saying my comments are meant to be helpful, not hurtful. But, at least to me, you are really talking apples and oranges.

While it seems that you have invested some amount of time looking at these engines and pondering design issues, you don't mention if you would want to stay with the AIR COOLED feature of the GX engines or develop some sort of liquid Karting Kooling system. Which, in fact, would be necessary to utilize the marine outboard power head of most any size or brand for what you are suggesting.

Almost all of the outboards in the horsepower "band" that MIGHT adapt are designed with ATMOSPHERIC, or open, LIQUID cooling systems with "wet" exhaust. In order to convert one for land use with varying elevation experiences you would need to design either a pressurized, closed loop, liquid cooling system with a "dry" exhaust manifold or come up with something possibly no one else has ever heard of like a "flux capacitor" sort of gizmo for heat transference.

Again, I'm not trying to be rude when I say that; unless you are the owner of a fairly high tech machining and material fabrication shop, any attempt to "convert" an outboard for karting would probably be a hack job of the highest order, resulting in a vehicle that might go fast, with a big enough engine, but could weigh well more than TWICE what you are driving now and cost TEN times as much. High speed cornering might not meet your expectations either.

Can it be done? You bet! I have no doubt. And, if you do have some success gettin er done, would you post some photos of the finished product? If you could do it well, you might also get rich very quickly and surly have me eating every word of this post.;~)

Good luck to you sir!
 
Thanks for the reply.

The Honda GX360K1 is a liquid cooled engine.

I plan on custom fabricating an exhaust manifold and keeping to the liquid/ water cooled nature of the engine.
I would build a 'normal' liquid cooled cooling system, but would have it pressurized and have it controlled by a thermostat.

My biggest set back is that I don't know where to find one of these engines, or if I could mount it in away I would be happy with. Since the engines are pressure lubricated, I can mount it however I want, but because I would like the engine to stay parallel to the drive shaft/ axels for less power loss to the wheels, I see myself having issues with a transmission set up.

I don't think I would ever be able to get this project done unless someone just gave me a Honda BF20, a small shop and plenty of piping/ quarter inch aluminum plates(to cut into what ever I need/ Brackets for mounting, support ect).

I already have multiple plans drawn out...
 
I stand corrected! I guess I was thinking GX390 with my little diatribe.

As far a finding one, the 20 twin or BFD 20 is one of the most prolific outboards in use today. But, they are EXTREMELY rugged and I predict that most will last in excess of 20 years service for most people if adequately maintained.

These are used extensively in the rental boat business and those "fleets" tend to be sold off in lots at auctions. But that might be a good place to start looking for one. When these businesses are finished with a particular series of equipment, the outboards will be in varying stages of disrepair and cannibalized. That would be the way to pick up a viable power head cheap. A guy buys a couple of pallets of outboards and may sell you one right then and there.

I'm not convinced that you will find it all that easy to adapt a dry manifold but you've proven me wrong once today already.

As far as keeping the engine horizontal for "less power loss to the wheels", I would just point out that a "T" or "L" drive is...well...still a "T" or an "L" whether horizontal or vertical so I would think center of gravity and offset would be a bigger factor in engine placement.



If you do want to lay the engine down to get the crank on the horizontal you will also be fabricating at least an intake adapter if not a manifold to get the carb in the upright position.

That would at least facilitate running a cooling fan off of the flywheel. Or would you go electric?

If you really want to see pics and diagrams, you could find a Helm Inc. shop manual and have pretty much all you need.

Again, good luck and have a good time if nothing else.
 
I plan going all electric and computer.

Getting rid of the carb, and replacing it with a custom fuel injection kit from MBE http://www.mbe-motorsports.com/catalog/product_info.php/products_id/190 opens the potential for more power and control through careful tuning and gets ride of the altitude issues.

Also, the GX360 has been put into a gokart before, so I'm determined to do it as well. I bring up the BFD20 engine because of it's OHC Head/ Valve cover. It's much nicer and better to look at then the regular GX360 from the HT3813 unless you find a GX640 out of a HT4814, but those are 10x's as rare as the HT3813's which are already rare.

GX360:
162.png


GX640:
154.png


In the gokart(GX360 from HT3813)
in%2520cart.png

in%2520cart2.png

in%2520cart3.png


Video:
http://www.youtube.com/watch?v=aT7Wo-so4T8&list=FLmkHdnUckSSPRSu7RPpTYuQ&index=329


Also, this BF50 head is nice. Is this style what I'm looking at on the BF10/ 20 also?
http://www.youtube.com/watch?v=tXL39NZj-RM

BF vs GX:
BF10/20 D
1.png

2.png


GX360/640
48.png



compare.png

BF10 http://www.youtube.com/watch?v=QLV7Wp31jag

BF10 also sound identical to the GX360.
http://www.youtube.com/watch?v=xZXQ2aMkWLo

The GX360/640 engines are probably my best, safest and easiest ways out on this, but I'm up for a little challenge just to get the better looks, higher revving engine from factory, and the power straight out the box. The GX360/640 engines aren't contact engines (valves and pistons ever touch) so revving high there shouldn't be a problem, but spun bearing scare me. The BF10/20 engine obviously revvs higher.
 
Not sure about the 50 but the 10 and 20 are both interference with cogged timing belt. There is a 50 fuel injected model but I don't know too much about it other than it would be UBBER expensive as a platform for what you propose. The additional cylinder would make for a much bigger footprint in the engine bay as well.

addhttp://www.boats.net/parts/search/Honda/Outboard%20Engine/0/BF50D%20LRTA%20/CYLINDER%20BLOCK/parts.html
 
You certainly have researched this a lot. Congrats on that. However, it seems that you might be biting off a big hunk of pain trying to adopt that BFD 20 to your needs.

Just some thoughts from an old guy who literally grew up in a garage, and did some serious drag racing many, many years ago, but doesn't know a thing about karting...

If you want to try the Honda BF 20, it looks like you will need to re-work the entire cooling system, the fuel system, and the exhaust system. Furthermore, I don't see how you can handle lubrication given the horizontal orientation you are looking for. Furthermore, it seems to me that your desire for liquid cooling may be self-defeating. The extra weight of coolant, pump, radiator/heat exchanger could easily overcome the power/rpm advantage you are seeking.

I'm not sure how much weight is playig into your calculations, but it seems like some decent alternatives to your base engine selection would be Briggs & Stratton and/or Kohler.
 
The BF20 and GX360 are pressure lubricated. Doesn't matter which way they are sitting, oil will be supplied allover.

I'm 16 so this is why I'm biting off so much, just trying to be creative.

As for the weight, I currently have 5HP Tecumseh PowerSport which gives me hell periodically. But at the same time I runs like a bat out of hell when I get it off its ass. I weigh 185, 5'11". The gokart is a two seater Manco 415. Est. Weight all together is roughly 400-500lbs. The GX360 with the full cooling system weighs about 100-110lbs vs the Tecumseh. 5HP vs 13HP. 7-8lb-ft vs 25-28lb-ft. I would believe the weight difference pays off and the result is slightly better performance. Plus with my gearing (Lawnmower transaxle) I can set the gear ratio to be geared for about the same 45MPH (with over drive 60MPH) but in the process have tons more torque!

Who knows, I'm just dreaming big I guess.
 
lookingforanswers,

Yep, you may be dreaming bud, BUT THAT'S WHAT IT"S ALL ABOUT at 16!

I can think of some other young "dreamers" that I've heard of that did ok...A.J. FOYT....Bruce McClaren....Roger Penske...Carrol Shelby...Dan Gurney....and California's own Parnelli Jones ( I like to drop his name because my dad worked for him) to name just a small few. Look Parnelli up on Wikipedia and you will see he started pretty young with his passion. They ALL did! That's why they got so good!

As an "old fart" whose time has come and gone and....."come again??"....:), it warms the heart to hear about young men like yourself that have interests and goals in something other than hangin' out and playin' video games.

Go ahead and dream all you want but make sure that you don't let anyone talk you out of DOIN' either!

Good luck to you sir!
 
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