2-stroke vertical engine [Archive]

brendan

12-23-2007, 12:53 PM

I've read how it is not feasible to convert lawmower engines for a go-kart, but it seems this is mostly due to the oil pickup issue when mounting a vertical engine horizontally. But would a two-stroke engine be much easier? It seems like I'd only need to build a mount and figure out something with the carb, right?

I have a 5HP two-stroke engine from a LawnBoy mower that I never use anymore and my son's kart is in need of a new engine.

Has anyone done this before?

Russ2251

12-23-2007, 01:10 PM

kibble

12-23-2007, 01:23 PM

A two stroke engine shouldn't matter what position the engine is in. The oil is part of the fuel mixture and as long as you have a way of supplying the fuel to the engine, it shouldn't be a problem.

robertdjung

12-23-2007, 02:11 PM

I've read how it is not feasible to convert lawmower engines for a go-kart, but it seems this is mostly due to the oil pickup issue when mounting a vertical engine horizontally.

also the carb orientation / gas supply.

But, yes, that is an excellent candidate for a go kart!

Russ2251

12-23-2007, 02:32 PM

Diaphragm carburetor is key to the enterprise. Orientation no longer an obstacle as they work in any position. Tillotson HL's work best (so far).

2or3wheels

12-23-2007, 04:23 PM

2-stroke are the best, you can mount anyway and if you have a diafream carb as stated above you could mount it upsidedown sideways and inbetween.

brendan

12-24-2007, 12:40 PM

Russ, so did your LawnBoy have a diaphram carb on it? Or is it likely something I will have to buy separately? Thanks for all the input.

Fuel delivery (to the carb) won't be a problem because the tank is mounted up high on the seat already.

Russ2251

12-24-2007, 06:22 PM

Diaphragm carbs were never used on L-B engines to my knowledge. Although not absolutely necessary, I strongly recommend the use of diaphragm carbs. They have the benefit of omni-directional mounting and smaller overall size for any possible clearance issues. An intake manifold or adapter plate has to be fashioned so that engine can accept new carb. L-B carburetors have a 52mm center to center bolt pattern while a more popular and easier to get carb is 43mm center to center.
Before I go any deeper with this, be warned that this isn't a cheap solution to replace an engine. I did it for the novelty of it and for my appreciation of the 2 cycle engine (pretty soon there won't be anymore). Approximate costs:
Clutch: $106
Carburetor: $30 (Ebay Tillotson HL new old stock) or about $100 (Walbro WGA-10-1 new)
Metal needed for custom made engine mount: approx. $50
Crankshaft work: $30
Total cost is between (roughly) $216 and $286.
You can buy a new engine for much less than this. If you still want to go through with this, just ask away. I will answer all.

Pic on left uses adapter plate w/Tillotson carb. Pic on right is custom intake manifold with Tecumseh snowblower carb. A bowl carb can be used with this setup.

JerryAssburger

12-25-2007, 12:33 AM

Very nice work! What are you running for gear ratio? I have a Briggs 2 stroke (Supposed to be about 4.5hp) but it has a 7/8" shaft... nothing but a belt clutch will fit it. Flipping the carb 90 degrees was no problem, but that shaft!.... Have you clocked that Kart yet?

Jblankster

12-25-2007, 12:35 AM

i think he said something about 52 mph?

Russ2251

12-25-2007, 06:13 AM

Engines I've converted are 7/8 inch shaft. I used 1" OD X .065 wall 316 stainless steel welded tubing to enable shaft to accept 1" bore Noram (#160157) 17 tooth-#35 chain centrifugal clutch. 2 flats had to be ground on crankshaft for clutch collet set screws. Ideally a key way should be cut but was just too expensive ($250 at local machine shop) and works just fine without one. Driven sprocket is 72 tooth making drive ratio 4.235:1 and does 42 mph without breaking a sweat. This is still a work in process. Currently I am converting a Lawn-Boy DURAFORCE 6.5 hp for this kart. When completed, should do over 50 mph.

Pics 1 and 2 show clutch setup (model "V" engine)
Pic 3 is 6.5 hp DURAFORCE (last Lawn-Boy 2 cycle produced)

2or3wheels

12-25-2007, 10:05 PM

You can find lawn boys with carb issuses for less that 30 bucks. Thats around here though. I use ww.craigslist.com just clikc on your city and there you go.

Russ2251

12-25-2007, 11:05 PM

Never had a bad L-B carb out of the 8 or so engines that I have modified. They just aren't up to the task of giving me the high rpm's that I require and need replacement for that reason. Biggest problem is CDI failures ($35 to $40) which sometimes I can repair using my secret weapons.

Burning Rubber

01-05-2008, 03:59 PM

most lawnmowers don't come with diaphragm carbys do they. I hav a 2 stroke 100cc B&S engine that i am thinking of putting onto my go kart

Russ2251

01-05-2008, 04:29 PM

most lawnmowers don't come with diaphragm carbys do they.

There are non that I am aware of, but it is possible. I did see one many years ago on a 2 1/2 hp Tecumseh reel mower.
You have a potential collectors item in your possession. Briggs & Stratton made them only for a couple of years until the market for them disappeared. I just missed getting one from Ebay a couple of months ago. The bids on this engine far exceeded the $100 maximum I was was willing to pay. I'm curious as to how you got it and do you know what diameter of output shaft is?

JerryAssburger

01-06-2008, 01:28 AM

I've got one of those B/S 2 stroke engines. A guy who owned a landscaping business gave it to me to tinker with. It's a 7/8" shaft. Supposed to be 4.5hp and built for B/S by a japanese company like mitsubishi. I'll try to remember to take pix tomorrow of it for this forum. So far, the carb has been rotated (EASY) to run in the horizontal position, but that #$#%ing 7/8" shaft is keeping the project from going much further. Russ2251,... what kind of safe RPMs can a stock LawnBoy engine turn? My Power-Mech teacher back in '81 reasoned that since the LawnBoy was intended to spin at 3600 rpm (Something about Maximum Blade Tip Speed) that they might not handle much more. Never having my own LB to play with has left me wondering. I'd love to know how well the B/S engine would do. That video of your Kart is very impressive and encouraging!

JerryAssburger

01-06-2008, 01:31 AM

Watched the video again... Good Lord, that thing scoots!

Russ2251

01-06-2008, 11:19 AM

that #$#%ing 7/8" shaft is keeping the project from going much further.
I used 1" OD X .065 wall 316 stainless steel welded tubing. Get it here: http://www1.mscdirect.com/CGI/NNSRIT?PMAKA=01412857
Pressing a section of tubing over length of PTO will make it a usable 1 inch diameter shaft. I used a Noram clutch (1 inch bore) which meets my needs. Get it here: http://www.heeters.com/kartclutches.shtml (http://www.pittauto.com/83059)
See attachments in post #12 above.
I don't know if this will work on your B&S.
As far as rpms are concerned, I don't know what maximum "safe" rpms would be. Bear in mind that these engines are designed to withstand blade strikes such as hitting stumps and boulders etc. I have seen shafts bent at 10 degrees or so and still ran fine meaning NO internal damage. When I do the math I find I'm running at about 5200 rpm. I'd like to get 7000 rpm as a minimum.
Engine in video is/was a model "F" Lawn-Boy @ 4.5 hp which pushed me around at 42 mph. Fun factor is about a 9.5 out of 10. I have since acquired a 2003 Lawn-Boy DURAFORCE @ 6.5 hp. This engine is now mounted on kart and is, as yet, untested. The real beauty of the DURAFORCE is that it is more easily modified to increase HP. Increasing compression ratio is first thing I am looking at.

JerryAssburger

01-07-2008, 09:28 PM

HOLY COW, Look at thing! Those DuraForce engines must be rare! Never seen one before. The local goodwill had the smaller lawnboy for sale for $20, but I need another engine like I need a hole through the skull. Thanks for the links! You made my job MUCH easier! I think I'll try to mount all this on my LowRider, once I get the parts. I think I speak for a lot of us when I say, I can't wait to see what happens next in your shop!

JerryAssburger

01-07-2008, 09:46 PM

...I wonder how hard it would be to find an expansion chamber off of an old 2stroke dirtbike of approximately the same CCs? Probabbly harder than $%% to tune, though. I'll sneak out and take pix of that B/S engine right now. Just remembered! (DOH!)

JerryAssburger

01-07-2008, 10:22 PM

Hi-
Sorry about the poor quality of the pix... My camera doesn't do flash too well. It's physically about the size of a Briggs 90000 series engine. I've ran it in this position, and it seems to run fine. I forgot about the heavier flywheel issue, but to be honest, it seemed okay, running on the the test bench. The carb and air filter are rotated 90 degrees, and that's why the air intake for the filter is in the "wrong" position, if it were to be mounted on a mower.

Russ2251

01-08-2008, 05:12 PM

Those DuraForce engines must be rare!

Rare only because L-B only made them for a couple of years. Thank the tree huggers for that (CARB, EPA, Al Gore et al). Some folks are dumping these mowers at a phenomenal rate because they believe that these machines are causing global warming. It's all pure Bull Stuff. Their loss...my gain. I have several 2 cycle engines including 8 Lawn-Boys, 2 Clinton kart engines, and a couple of J-321 Jacobsen's and a dozen or so B&S 4 cycle engines dating back to the mid 1930's.
I have seen posts in some karting forums (including this one) that describe 2 cycle engines as being "too complicated" or "too hard to work on". Nothing could be further from the truth. Only 3 moving parts bring them to life compared to a 4 cycle which has 2 to 3 times that amount and, not to mention, twice the weight. 2 cycle engines are high performance by nature and need little to make them even more so. Someday, perhaps soon, nobody will be manufacturing them.
Anyway...let us know how things go.

2or3wheels

01-09-2008, 09:20 AM

Oh 2-strokes are much more powerful and are sooooo easy to work on. people like 4-strokes for the torque the non-premix(unless injector) and the length of life. But if you mix the gas right you get very minimal smoke and if you do basic matinence i bet it will last just as long as a 4-stroke. Hoefully ill get a welder soon(getting job) and will start the 2-stroke madness.

How many cc's is that, it looks quite larg, maybe 50 or so?

Russ2251

01-09-2008, 03:59 PM

How many cc's is that, it looks quite larg, maybe 50 or so?

Not sure who you're asking. My Lawn-Boy (pic in post #19 this thread) is 141cc's or about 8.6 cubic inches. Smaller than Honda GX200 @ 196cc's but same horse power.

JerryAssburger

01-19-2008, 09:26 PM

Russ2251

01-20-2008, 08:46 AM

No clue on the B/S engine, except B/S tends to make the first digit of their model # cubic inches, so I'm guessing the B/S motor is between 8 and 9 cubic inches. I'll put it on something, someday. It was free to me, so I just keep it stored.

This engine is also 141cc's and as you noted in an earlier post, probably Japanese. Interesting to note that this engine has been discontinued but B&S makes (in USA) a 2 cycle engine called an RTEK (Toro) or DURAFORCE (Lawn-Boy) for snow throwers. As best I can tell, these current incarnations are exclusively snow engines. My Lawn-Boy manufactured DURAFORCE is a reed valve mower engine (6.5hp) while the Briggs manufactured RTEK or DURAFORCE is piston ported making it somewhat less hp (perhaps 4-5) than the reed valved counterpart. I hope I confused everybody!:confused: :D Pic on left is snow engine (note Briggs logo), right pic is mower engine (no logo). These engines are essentially the same other than induction system. I just purchased a new one on Ebay.
http://www.smallenginewarehouse.com/product.asp?PN=84333-0199&desc=Briggs+Engine+Two+Cycle+Horizontal+25+mm+X+4+ Shaft+110+Volt+Electric+Start+No+Fuel+Tank+Made+fo r+Toro

2or3wheels

01-20-2008, 07:24 PM

i have 2 of the ones on the left, look on the crank, one of the ones i have has those rollers but the onlder snow pup one does not.

Sk8r_On_Fire_

01-21-2008, 03:06 PM

well, since it is two stroke, i believe that you can just turn it on its side. But, i may be wrong but im thinking that since the oil is mixed with the gas it shouldnt matter if it is on its side

Russ2251

01-21-2008, 04:17 PM

i may be wrong

It's what I do. Don't know what you're missing until you've run a kart with a 2 cycle. The exhaust smell alone will beckon.

JerryAssburger

01-23-2008, 12:08 AM

How cool! GREAT FIND! So mine must be the piston port model. The price in the new one is a steal! Thanks for the link! This is going to get a few rusty gears in my head spinning!..... PLZ PLZ keep us posted on your results!

JerryAssburger

01-23-2008, 12:14 AM

WOW... from the pix, it looks like its a diaphram carb and a 1" shaft! I'll bet those 4 holes around the crank could be adapted to a Comet Torq-a-Verter. Nice little powerplant options, there.

Jblankster

01-23-2008, 04:56 PM

hmm. i got a 2 stroke toro snow blower :D if we ever get a new one, I KNOW WHERE IM GETTING MY NEXT ENGINE! :p

Russ2251

01-23-2008, 07:07 PM

WOW... from the pix, it looks like its a diaphragm carb and a 1" shaft! I'll bet those 4 holes around the crank could be adapted to a Comet Torq-a-Verter. Nice little power plant options, there.
Hokey smoke Bullwinkle!...Ordered it Sunday and received it today. That's quick. Next time I need an engine, I'm going here first.
http://www.smallenginewarehouse.com
Anyway...At first glance. it is a thing of beauty but is a little heavy for a 2 cycle. It is brand new.
A few things here have to be changed/removed/modified/disabled.
1.) Bowl carburetor and intake manifold has to go. Adapter plate will be used to accept a Walbro wb32 or a Tillotson HT5A. I will have to see how this goes as these carbs are untested for this displacement range.
2.) PTO is actually 25 mm or 0.984 inch meaning that I will have to use .007 shim stock to make up the difference to fit 1" bore centrifugal clutch. I've done this before and is no big deal.
3.) 120 volt starter will go away along within ring gear on flywheel.
4.) Key way will have to be widened to accept a 1/4 inch key. It is now 5 mm or .194 inch. A difference of .056 inch. I'm on the fence about this mod.
5.) Governor....needs no explanation. Complete removal via 1 small screw.

As far as torq-a-verter goes....simple answer is...I just don't know. Unless someone wants to donate one to the cause, I have no way of checking for fit.

Jblankster

01-25-2008, 07:05 PM

^get a vid of it running and/or on a kart!

Russ2251

01-25-2008, 07:35 PM

Maybe mañana. I have it temporarily mounted on 5/8 plywood and needs fuel tank. Just to clarify...My converted Lawn-Boy DURAFORCE is actually more powerful (by 1.5 hp) and will be more impressive performance wise.
These engines are fraternal rather than identical twins. As stated in an earlier post, the L-B is reed valve while the Briggs (Toro) is piston ported. Piston ported engines generally do not perform as well as reed intakes (a few exceptions) hence the lower horsepower rating on the Briggs. I found it curious that L-B takes 32:1 oil mix while the Briggs engine takes 50:1. I'm not sure if this due to the way it is ported or the fact that this engine is meant to be used in colder conditions. The hotter a 2 cycle runs...the more oil it needs. I will run them both with 32:1 ratio. More oil never hurts...just a little more smoke.

Russ2251

02-07-2008, 06:41 PM

Mounting of new Briggs 2 cycle snow engine on kart almost completed. I will post video on youtube at that time.

I recently acquired a Briggs Quantum 6.5 hp vertical shaft engine. My intention is to (somehow) mount this to my kart.
There is nothing impossible in this idea. Supporting this monstrosity will be the biggest challenge given the diameter of oil sump with 3 bolt holes. I have used cantilever type mounts on my 2 cycle conversions which works well.
I think I've nailed down (heavy use of A. Einstein's "thought experiments") any lubrication issues. This engine has an oil slinger, and as I mentioned in another post, may work in horizontal position as long as slinger is making enough contact with oil while in upright position.
If slinger doesn't work, I can remove it and make a custom oil dipper to bolt onto rod cap which would solve lubrication problems, but, may create some balancing issues. Any thoughts, opinions, suggestions, etc. are greatly appreciated! PHEW...

alfalfa

03-02-2008, 05:30 PM

how did you hold the clutch in position?

alfalfa

03-02-2008, 05:37 PM

I'm thinking of putting a duraforce on a minibike

Russ2251

03-02-2008, 06:16 PM

Requires removal of crankshaft from engine.
2 flats have to be ground onto crankshaft end for set screws, on clutch, to get a grip. Knowing somebody at a machine shop helps.
See related posts here:
http://www.diygokarts.com/vb/showthread.php?t=910

2or3wheels

03-02-2008, 08:52 PM

why not get a set screw?

Russ2251

03-02-2008, 09:28 PM

why not get a set screw?

:huh:

kibble

04-06-2008, 01:00 AM

Some folks are dumping these mowers at a phenomenal rate because they believe that these machines are causing global warming. It's all pure Bull Stuff. Their loss...my gain.

There's a commercial running on one of my local radio stations 97.1 "Free FM" where they claim that lawnmowers can cause up to 93% more pollution than an automobile. The commercials purpose is to trade in your old lawnmower for a new "Newton" electric lawnmower that doesn't cause ANY pollution. You pay the difference, of course. Ummm... you still have to charge it and most power plants run on coal as fuel. I was like, WHAT???? First of all, you don't run a lawnmower all the time. Second, yes a car does have a catalytic converter, but that doesn't mean that all of the exhaust gases get catalyzed. Just another way to get money from people. :ack2:

Russ2251

04-06-2008, 06:08 AM

Just another way to get money from people. :ack2:You nailed it and that's ALL it is.
There is no empirical evidence that global warming is man made. Global warming actually PRECEDES elevated carbon dioxide levels by a couple of centuries. No one explains this fact.
There was a time when there were no polar ice caps.
Now, it is claimed that they are melting and everybody's getting upset. Many scientists know this is a cyclic event as did the dinosaurs who witnessed the formation of the frozen poles.
Sorry about the :offtopic: post.

2or3wheels

04-08-2008, 06:10 PM

you screw a usually allen geaded screw in and it holds it in place.

I like karts

05-04-2008, 05:17 PM

why did you take the video down? I can't see it

Russ2251

05-04-2008, 06:28 PM

Here ya go. Check my other vids while you're there.
http://youtube.com/watch?v=U_fapdfrMyc

JerryAssburger

05-16-2008, 07:29 AM

Hey guys- wasn't sure where to put this.....
I got the feeling at least 1 of you is bidding on this one!
http://cgi.ebay.com/ebaymotors/97-ARCTIC-CAT-KITTY-CAT-SNOWMOBILE-ENGINE-TAKE-A-L-K_W0QQcmdZViewItemQQcategoryZ100456QQihZ008QQitemZ 180242634793QQrdZ1QQsspagenameZWDVW

...I've never seen a snowmobile motor with a regular centrifugal clutch!

crazycart

05-16-2008, 02:52 PM

Thats for a kitty cat,its a very small sled meant for young children,most newer "mini snowmobiles" run the cent. clutch too

JerryAssburger

05-17-2008, 12:31 AM

Yeah- you're right. Only 60cc and supposedly the sled is governed to 8mph. It kinda LOOKED like one of those Clinton Kart motors...?
Oh well!

crazycart

05-17-2008, 09:07 AM

I once saw one at a swap meet that had been modified to about 13 hp,i think they are around 6 stock,the guy wanted 600$ for it :ack2:

I like karts

05-21-2008, 10:35 AM