[Diy_efi] Re: Fuel injected small engines

[John Smith]

I'm currently working on putting turbo/EFI on a 10hp(450cc) Briggs right 
now. Look at the archive back through January and you'll find a bunch of 
posts. I have a Ford low impedance 30lb/hr injector that I will be operating 
with a simple 555 monostable and a TIP3055 power transistor. The timing 
resistor wil be the TPS on a Nissan throttlebody I have. Pulse width will 
only be controlled by throttle position, not actual airflow. It will 
probably flood if the throttle is snapped open. It will also likely run 
extremely rich until boost kicks in. The 555 will be triggered with a photo 
interrrupter on the crankshaft. That means that it will be a sort of batch 
fire system injecting half the fuel on every crank rotation. I also have a 
small 2:1 belt drive out of a photocopier that I could use to make the 
injector fire only on the intake stroke, but that will be more work. The 
limited control a non-digital ECU has means injector timing is almost 
non-adjustable in relation to crank position. Now that I think about it, I 
may try to find the whole EFI system from a latemodel streetbike. My goal is 
simply to make as much power as I can before the engine fails; usability is 
not really a concern.

For a boosted Kohler pulling engine, you could use either EFI or a carb. If 
you want to intercool it(highly recommended, esp w/air cooled engines), you 
can still use a carb. It will have to be blow-through. You need a large bike 
carburetor with a Nitrophyl float and a fuel pump with a 1:1 boost 
referencing pressure regulator. The carb will probably need other 
modifications unless you put the whole thing in an airtight enclosure, which 
also works. Just be sure you have a head plate holding the top of the engine 
down....

>Message: 1
>Date: Thu, 26 Jan 2006 15:57:28 -0800 (PST)
>From: joel sprague <joel_400 at yahoo.com>
>Subject: [Diy_efi] Fuel injected small engines
>To: diy_efi at diy-efi.org
>Message-ID: <20060126235728.66634.qmail at web30111.mail.mud.yahoo.com>
>Content-Type: text/plain; charset=iso-8859-1
>
>I was reading the recent posts about the Suzukis and
>Geos and was wondering, has anyone ever built a fuel
>injected small engine, such as a Kohler?  If anyone
>has and would like to share some info on doing this it
>would be appreciated.  I'm working on a garden tractor
>puller and that would be nice to have, instead of a
>carburetor, especially when it comes to running a
>supercharger or turbocharger.  Sounds nuts, but I'm
>working on that right now.
>Joel