Carb to Fuel injection conversion?

[hz900]

'92 Prostar 205 w/ holley dual feed carb


I've heard there are kits to convert the carbed engines over to fuel injection, is this true. If so where do they sell them. The ones I've heard of are throttle body injection kits, is it possible to install a multi-port injection system?

Also is it worth it? I like fuel injection more than carbs, I know more about how to work on them, and they are typically more reliable and throttle response is better IMO.

Is there anyone on this board that has done it, I'd like to get some first hand experiences on pros/cons.

[flipper]

I put an injected engine in my '91 prostar 190, and love it. I have seen the kits for cars. It is nice not having to pump the throttle, and crank the engine for a while.

[jake]

I was seriously considering the Holley pro-jection marine conversion kit. It's throttle body, seems simple, and isn't too much more expensive than a new carb.

I didn't pull the trigger, because of mixed reviews I read on-line and feedback I got here from JimN and others more knowledgeable in these areas than I, but if you're considering the conversion, you might want to check it out as an option.

[erkoehler]

You can probably sell your 92 and upgrade to an EFI 94 for maybe $2-4,000

[hz900]

Originally Posted by erkoehler

You can probably sell your 92 and upgrade to an EFI 94 for maybe $2-4,000

I do all my own work. For $4k I could easily drop a fuel injected crate motor in the boat. I'm thinking more along the lines of $500.

[east tx skier]

I think the Edelbrock MPI kit is over $1K. When I mentioned this to my local ski boat mechanic, the answer I got, and the answer I hear most often, is that it just isn't worth it and if you want a fuel injected boat, sell yours and buy a fuel injected boat. Like Dan, I'm not mechanical. But this has been the consensus from the people I trust most on the subject.

If you're looking to spend $500, spend it on a Holley 4160 single feed marine carb. Greatly improved reliability over the 4010 you have on there now IMO.

[tdaines@hotmail.com]

Hey, I have had a lot of experience in this - and there is hope for you! TBI Injection is fine for the reliability that you're after, and a complete kit with in-tank fuel pump, high pressure lines, filter, and the TBI will run you around $1500 and take a fairly skilled back yard mechanic 8-10 hours to install. Electrical work is also required.

Port Injection aftermarket kits for marine apps don't really exist - you'd have to retrofit from a totalled boat, including HEI ignition and the manifold. It would be a major hassle...

The good news is this: I've been through it twice on my last two PS190 boats. The simple fact is that marine carbs aren't built to last 15 years. That doesn't mean, however, that they aren't any good. If you want an easy, fast, painless solution, I'd go down to the local NAPA store in your town, and have them order you a brand new HOLLEY Marine carb for your boat (4000 series, probably). They retail at MC dealerships for $730, but go for $509 at NAPA!

Trust me on this one - I've done it twice, and my boats start on the frist turn of the crank, and run like a fuel injected boat. Most people can't believe how well my boats run...

Good luck!

TIM

[Credo]

The only question that I have with using a car multiport injection system ona boat would be the 02 sensor. I know that Ford ECU's take their main readings from the MAF and O2 sensor wouldn't a wet exhaust system corrupt the reading from the 02 sensor? And make the engine think its running rich?

[gr82bgreen]

Originally Posted by Credo

The only question that I have with using a car multiport injection system ona boat would be the 02 sensor. I know that Ford ECU's take their main readings from the MAF and O2 sensor wouldn't a wet exhaust system corrupt the reading from the 02 sensor? And make the engine think its running rich?

You could run it without the sensors. it would be in open loop and would set codes, but it would run fine. The maf was not used on the older speed density system, but that system is calibrated to the car or trucks camshaft. I think the boat cam would run ok though. I don't know how the prograqming would translate form a car or truck, to a boat though. Ive heard its a bad idea to install automotive efi on a boat. probably cheaper and less headaches to upgrade to a new boat with efi. You would need lots of new parts, intakes, new fuel pump and lines, ecu, a wiring kit to make it work. would have to find a dry sealed place for the comupter.

[JimN]

Originally Posted by gr82bgreen

You could run it without the sensors. it would be in open loop and would set codes, but it would run fine. The maf was not used on the older speed density system, but that system is calibrated to the car or trucks camshaft. I think the boat cam would run ok though. I don't know how the prograqming would translate form a car or truck, to a boat though. Ive heard its a bad idea to install automotive efi on a boat. probably cheaper and less headaches to upgrade to a new boat with efi. You would need lots of new parts, intakes, new fuel pump and lines, ecu, a wiring kit to make it work. would have to find a dry sealed place for the comupter.

If you disconnect the TPS, it will default to 12% throttle position at all times and that won't run "fine". If the MAP sensor is disconnected, the ECM will have no idea how much fuel to deliver, so that will default to a setting that won't allow good performance. If the ECT is disconnected, the ECM will think the engine is at about -40°F, or below, so it will run exceptionally rich. If the knock sensor is gone, it will want info, so it will prevent correct timing advance and throw a code, too. How does this qualify as "fine"?

A really easy way to upgrade to EFI is to buy a GM Performance Parts crate motor, like the 350 RamJet. 350HP/390Ft-lb of torque, it uses the same ECM and any GM dealer can service it when the warranty is still in force. The thing about MC- they calibrate teh engine to the boat, not a generic weight load.