Is fuel injection a good thing on these VP powered boats?

Just looking for tribal knowledge is opinions of fuel injection on the marine motors.

I'm an electrical engineer and surely understand EFI much better than the carbs. Just haven't worked as much with carbs to fully appreciate the finer aspects of tuning them correctly. I can read a book, but carb tuning seems a hands on experiment with a finite bit of science behind it!

Re: Is fuel injection a good thing on these VP powered boats?

EFI on boats is basically the same as on cars in regard to advantages and disadvantages. Being an electrical engineer doesn't help either. The problem is not so much understanding it, as it is in how to fix it.
With EFI, if you don't have the diagnostic tools, the manuals and the skills to use them, and it breaks. then you will have to find a tech to fix it. Just as if you had a carbed engine.
There is nothing in the marine ECM that is re-programmable like the automotive side. No fancy race "Chips" you can throw at it.

Re: Is fuel injection a good thing on these VP powered boats?

The EFI engines tend to make more power out of the same amount of cubic inches because they run more efficiently, that said, without the proper diagnostic tools and the manuals, it's difficult to even know where to begin. With a carbureted engine, with the manual you can usually figure out the issue and rebuild the carburetor yourself with the proper rebuild kit and some mechanical skill. I like the simplicity of a carb, that's just me.

Re: Is fuel injection a good thing on these VP powered boats?

I ran carbed engines of various pedigree for over 40 years. I bought my first fuel injection 10 years ago, and haven't had a start problem since. I'll quit before going back to a carb if EFI is available for the horse power desired ...

Re: Is fuel injection a good thing on these VP powered boats?

The advantage of EFI engine control over a conventional carburetor and distributor is that EFI affords you much finer control of air fuel mixture and ignition timing. Finer control means you can squeak a bit more power, a bit better economy, and better emissions than you can with a mechanical system on the same engine. In order to take advantage of this a lot of time and effort goes into tuning the system, and tuning is everything. Because of this the OEM suppliers consider this knowledge proprietary and do everything they can to ensure that if you have any problems at all it must be taken to an authorized dealer for diagnosis and repair. The good news is that with basic care, these systems seldom give trouble.

Re: Is fuel injection a good thing on these VP powered boats?

Typically automotive engines are tuned from factory for best emissions at all power settings except heavy load where they are tuned for best power. I don't know how the marine engines are set up from factory, but I suspect that they do the same to keep in line with current marine emissions standards. There is no reason why a marine engine can't use the same tune as an automotive one and there is no reason to differentiate between whether the engine will be used in a small light boat or a large heavy one. The fuel and ignition maps are speed and load dependent. If the boat is over powered or is used at light loads most of the time it just won't use the areas of the maps that cover heavy load. On the other hand if the boat is under powered or is used at high power settings most of the time, it just won't use the light load portions much. If emissions are not a concern programmable EFI allows you to tune for best fuel economy at light loads, and best power at heavy loads. You just don't have this degree of control with a conventional carburetor and ignition system.

Re: Is fuel injection a good thing on these VP powered boats?

EfI to me is one more step in controlling the outcome of any engine. Even a old mefi map based system allows you to predetermine both timing and fuel afr every 200 rpm. Once you have the programming software and understand just what you are doing it is quite a tool. (Im not there yet). But if you think of it like this you can run a rich mixture from 1500 to 2700 say a 10/1 afr. from there its just as simple to start running 13/1@ 2800 to 4000 for econ and power and again back to a rich charge @ wot...Now timing you can play safe with the timing in all the rpm ranges or push it...and if you get into a lean situation there ae knock sensors that will tame it down a bit.

What efi lack is support for the average guy which makes it difficult to appreicate what it is capable of..With that said OS sensors are being made for marine along with auto tuning...Completely bypassing the need for understanding what is going on when mfg is comfortabel with that...probably not gonna happen but aftermarket is now supporting it things will change quite a bit.

http://www.dynojetcmd.com/cmd_marine.aspx

I really like the concept and for 600 its not a bad buy

Re: Is fuel injection a good thing on these VP powered boats?

I have experience with programmable EFI in both automotive and now marine, so I can speak from experience, not just theory. My systems are all speed density, late '80s early to mid '90s technology. I can't speak to any technologies newer than that. Newer technologies are better, but for back yard enthusiasts like myself I am limited in my tuning resources so that's what I stick to.

A well tuned carburetor and conventional ignition system can come close to the degree of tune that you can achieve with this older EFI technology. The key here is "well tuned". Few non EFI installations are tuned to this degree. The fact is that if you are capable of fine tuning a conventional carb and ignition system, tuning EFI will be a much easier for you with the added advantage that you will have finer control. Neither of these options are for casual tinkerers. It takes a lot of time, knowledge and dedication to make even small improvements, but that's kind of the fun of it all.

Getting back to the original post. There is no doubt in my mind that EFI can control an engine better than conventional carb and distributor. The downside to factory EFI is that you are now "held hostage" by the Original Equipment Manufacturer as far as diagnostics and repairs are concerned, but no more than if you were to buy a new automobile. It's just a fact of life with more complex technology. If you don't have the ambition to tackle programmable EFI, but still want the freedom to work on your own iron, then sacrifice a bit of performance and go with the old stuff. It all works, just to different degrees of precision.

Re: Is fuel injection a good thing on these VP powered boats?

since a carb is a glorified version of a toilet float, my suggestion is EFI. short of knowing the fuel system folks at Volvo Penta, or Mercruiser, the stock systems are not user tuneable. I wont get into aftermarket systems here.