Building a Homemade Fuel-Injection System on a Briggs and Stratton 5 HP Engine

Hello,
I would like to know if anyone has ever tried to implement a FI system for use on a small lawn mower engine. What would be involved in doing
this and would it work? Are there any DIY sites that discuss this or are plans available? Any other good references? Thanks a bunch.
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This begs the question . . . . . Why ?

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T.C. Mann wrote:

The closest I've heard is adapting a Honda 4 cyl ECU and injectors to work in a 2 cyl motorcycle engine. It worked, but I don't have any links for you.
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You know...I've wondered the same thing. I have an old Toro lawn mower that I use for odd jobs around the house. I think it was made in '75 or there abouts. Anway, It's a bit finicky to get started...easy to flood and really touchy to adjust the choke right. I'm sure most would call me crazy, but I think it would be a fun project to build a FI system for it.
Sorry...I don't really have any info or links...just moral support.

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Yeah, but the "fun" might go out of it when you tried to make a fuel pump and adapt it to the engine.
Bob Swinney

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I have contemplated this for a long time, but have never gotten around to actually DOING it. I have always wanted to build my own fuel injection system. I was thinking of injecting my VW dune buggy. Maybe get real crazy and turbo it someday(but I doubt it). I was on the SAE formula team in college. We modified a Haltech(I think?) injection system to run a bike motor. It worked fairly well. The engine controls has always been a cool idea to me. I want to do it, just to do it. If I had a serious application I would buy one of the generic off-the-shelf packages available out there, like what have been suggested. A co-worker has the megasquirt system on his Audi turbo. Currently, just using it for spark control I believe, and waiting to tie in the fuel.
JW
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biggest prob. will be to manage that little amount of fuel. i have built a couple for harleys and the idle circuit is the one that requires the attention to flow. but it is pretty easy one you get the basic principle down pat. volume and pressure are the only things you need to control. "try it-you'll like it" jim
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snipped-for-privacy@yahoo.com (T.C. Mann) wrote:

I haven't, but I'd hardly be surprised if someone has.
Let's see - you need an O2 sensor, you need a fuel pump, you need an injector, and you need a little computer to control it all. You may also need an array of other sensors, such as various temperature readings. So you'll be adding a generator if the mower does not have one. If it were me I'd add a better muffler along with the O2 sensor, since I just don't think the standard lawnmower exhaust is even remotely quiet enough.
Please share if more resources come in off line. I don't know about bothering with my lawn mower, but I've got an old motorbike that might enjoy the update, and it at least has an electrical system...so I'll be watching this thread.
--
Cats, Coffee, Chocolate...vices to live by

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wrote:
|| snipped-for-privacy@yahoo.com (T.C. Mann) wrote: || ||> I would like to know if anyone has ever tried to implement a FI system ||> for use on a small lawn mower engine. What would be involved in doing ||> this and would it work? Are there any DIY sites that discuss this or ||> are plans available? Any other good references? Thanks a bunch. || ||I haven't, but I'd hardly be surprised if someone has. || ||Let's see - you need an O2 sensor, you need a fuel pump, you need an ||injector, and you need a little computer to control it all. You may also ||need an array of other sensors, such as various temperature readings. So ||you'll be adding a generator if the mower does not have one. If it were ||me I'd add a better muffler along with the O2 sensor, since I just don't ||think the standard lawnmower exhaust is even remotely quiet enough.
There was plenty of FI out there before electronic vesions came out and made it cheap and easy. I don't recall the details, but it might be worth looking into building an all-mechanical FI system Texas Parts Guy
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I had a 1976 SAAB that had a mechanical fuel injection system. I was very simple and that motor had LOTS of balls. In 1976 most cars were nothing but smog pumps, but that old Saab didn't need any of the emissions stuff and ran very good.
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Ecnerwal wrote:

Gross overkill for the application. SInce you wish to operate at essentially constant rpm and nearly constant power at fairly well known temperature and pressure, the requirements are much less. Cars need to run over a wide range of environmetal conditions and over a wide range of speed and torque.
In the late 60's, I had a Cessna 205 which had an injected engine. There was a fuel pump and a bypass valve to control the pressure at the injectors and a throttle butterfly to control the air. IIRC, the throttle affected both the bypass and the butterfly and the mixture control affected the fuel pump or possibly was tied into the bypass. The injectors were partially pinched of pieces of copper tube that sprayed the fuel into the manifold just before the intake valves. Performance was good as was fuel consumption so the simple system obviously worked.
Ted
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replying to Ecnerwal, Jiix wrote: There are companies around that specialise in small engine efi systems, but on a lawnmower.... you would need it to be either electric start or have a charging system for 12 volts to run the unit ...www.ecotrons.com do 2 versions 50-300 cc and 400 to 800 cc if you wanted to have a kit..they are not exactly cheap, but speeduino.com do the same thing but cheaper. To run the ecu you would need to convert the rotary spark generator to become the crank position sensor, install a separate ignition system to make the spark instead, fit a fuel pump and replace the carb for a throttle body (replaces the carb and has the fuel injector installed in it)...you would have to do the tuning yourself to get the spark in the right time and then build a fuel map to deliver the right amount of fuel at the right revs and engine load.. I to am looking into this and thinking a single cylinder motorbike efi might be easier to convert and cheaper too
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T.C. Mann wrote:

We had a team build a hybrid electric car a few years back, for an SAE national university challenge. The engine and car were donated, so you had to use those parts. The engine, as I remember, was a Briggs&Stratton 2-cyl engine. The young woman who got herself elected project leader found an outfit that had been preparing to market small engine EFI systems when it looked like the EPA was going to require emissions controls on small engines. They had a kit with the computer and a few other components that she bought. She hooked up two of the injectors off the Ford Taurus, used the existing fuel pump in the tank, and one of the O2 sensors off the original engine, calibrated the thing, and it worked. I was rather amazed at the expertise of a 21-yr old mechanical engineer to pull this off! (The graduate-level electrical engineer working on the electronics for the main DC motor drive was ALL wet, ignored all my advice, and ended up with a car powered by a 90 Hp electric motor plowing sideways through a room full of people when the main power transistor shorted. There were people climbing benches and whatever to get out of the way! Luckily, no injuries on that one.)
Anyway, I do't recall the name of the outfit that made this kit, but it was apparently a configure-it-yourself setup, with a PC program that would allow you to do all the calibration, etc.)
Jon
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On Fri, 23 Jul 2004 16:57:02 -0500, Jon Elson
......and in reply I say!:
remove ns from my header address to reply via email

And now she's a mom with three kids, and he designs Mars landers, right? <G> ***************************************************** It's not the milk and honey we hate. It's having it rammed down our throats.
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Old Nick wrote:

(Snip)
Having a bad day, Nick? :)
Allergic to good news, are we?
--Winston <- 'Mr. Milk and Honey'
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Just a lead for you.
The fellas that race go carts have this. There's a cart class for "looks like a briggs- but do what ever you can to it." I've seen super charged fuel injected units.
karl
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T.C.
Have you tried contacting one of the news groups where they deal with building fuel injections. I've read about guys designing *and* building their own injection systems. Alt. autos fuel-injection is a start
Jerry
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This is about the best site I have found for DIY fuel injection systems. http://www.megasquirt.info /
Chris
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Think the "Karters" are already doing this. Especially the alcohol burners. Quite easy. They divert the pressure diaphram lift pump that fills the resevoir in the tank "float level" to the main mixture screw. From there straight into the carburetor using the existing port. They use the mixture screw to set the maximum mixture setting and let the rest go. Vacuum does not pull the fuel in. The system is pressurized. Works quite well for a racing setup.
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snipped-for-privacy@yahoo.com (T.C. Mann) wrote in message

Look here:
http://www.bgsoflex.com/megasquirt.html
Pete
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