Carb vs fuel injection?
 

I am pulling the motor out of my 25 outlaw this week to make some transom assembly repairs, (swivel pin and seal) replacement. I am currently running a slightly modified NA 509 mpi fuel injected motor. Over the winter I purchased a complete setup to switch over to carbureted.... Dart intake Holley carb, fuel pump and regulator, msd distributer,blaster coil, and msd blue box.
So my plan is to make the swap while the motor is out. I'm sure there will be a few other small things that I will need to purchase to complete the swap.
My feeling is that there is a little more hp and speed to be had by switching to carb. Most might say that fuel injection is better but others say if the carb is tuned right then it's just as reliable as fuel injection.
I will be selling the boat this summer. By going to a carb what is that going to do to resale make it better? Worse? Or not change it? I just figured that if the boat doesn't sell right away as the used boat market seems slow,at least I would be running the season with the motor setup the way I wanted it to be with a carb!

So guys what are your thoughts go carb or am I just being crazy!

All I have ever had was stock power. All of it has been carbed and have never had problems with it. At cold a couple pumps of the throttle and crank till they start. When warm just turn the key and they fire right off.

I think the main advantages to injection is they are easier to start and a bit better on fuel. What I do see is tons of posts when they have problems with the injection.

I like efi but carbs are perfect for the diy'er.only thing i don't like is between my cams and props I've got my idle set about 1300 in neutral to keep it running in gear.efi compensates to maintain a set rpm which i miss.so i guess im torn

1300 rpm idle? that's hard on drives !!!

1350 huber tranny's and #4's smooth as butter:evilb:

Odds are better when trying to sell a boat with a stock motor in it versus a modified motor.

To me thats going backwards..1970 technology.. fuel injection is so much nicer, just turn the key and go.

I have always thought the only advantage of carbs is they are cheaper. Everything i have read states when set up right, they are as good as fi. All things equal, i will take the fi boat with stock power long before the hopped up carbed up engine. Just one opinion and we know what that means.

Thanks guys!
I understand where you are coming from with regards to stock power, however I don't have stock power so I can only work with what I have. My current power is a 509 with upgraded cam, full roller setup, ported mpi intake, computer tune, and exhaust. So it's not to radical but still makes good power. If you looked at the motor you would never know that any of that stuff was done until A. you start it or B, you take the oil fill cap off and look in and see the gold rockers or C, tear it down. I just figured if I went with the carb setup it would be a little more self explanatory, easier to trouble shoot and tune. The motor has under 180 hrs on it since the rebuild but while the motor is out i am going to do a leak down test and probably send the heads out to be checked just for a peace of mind sortta thing. Either way when the time comes I will sell a turn key reliable boat.

100% fuel injection

Keep injection, sell boat.

For resale I would have to say FI would be much better, if you were keeping the boat and wanted to set it up your way then carb it.

the guys that like carb engines are the same guys that dont know how to work on EFI,,,,just saying..

Yep. Get with the times and go EFI. David Hasselhoff did back in '82....I think he was crankin out about 120hp at the rear wheels.

this is a moote point if your selling the boat really but.

Carbs are easier to tune for a old gear head cause they are use to them. and you dont need anything special to tune them

But EFI, is 100X better, the ability to control and adjust on the fly automaticly. the problem people dont like is you have to have the computer to tune it, and know what your doing.

But thats the same with a carb. if you dont know what your doing you not going to get it right either.

And the guys who don't like carbs, don't know how to work on anything!

That's why ''turn key'' idea gets their pants tight, so they can leave their west marine ratchet set wrapped in plastic and tucked in the cuddy. Anything more than a oil change and a random impeller, and out comes the credit card and repair bills from the mercruiser dealer.

I'd love to see some of the average do-it-yourself bar stool EFI cheerleaders, that recommend EFI on everything from a lawnmower to a airplane, go put together a custom Coil on plug port injected setup on a 1000+HP marine engine, build the system, tune it via their laptop, and have the engine running like a top. Oh, and the time frame to get it done is 30 days, not 3 years.

Very few can do those systems, eddie young, haxby, are no dummies. Its a little more involved than one thinks.

hmmmmm,,,not sure if thats a shot at me or not,,,,:lolhit:

All I can say is I have been doing this for about 33 years and been a GM master tech for the last 27 years now,,
been there done that,,points,,carbs,mechanical injection,,,TBI,,,MPI,Hybrid,,GM Volt,,downloaded programed ecm,pcm,,and I could tell you this a good running EFI engine is like a sore diick,,you cant beat it...:lolhit:

I disagree completely.

The ONLY set back is that for some reason its retarded expensive and not many do the custom tuning to marine boats. its not rocket science. I have been building and play motors for 15 years. Its retarded there is not mutiple ways to retune a Merc motor.

For example LSX motors (Vette, cameros, caddys, all gas cehvy trucks ect.) HPtuners, LS1edit, and more are out there for these open software options, you can load on a laptop an tune your custom set up. There is NO reason a Wide band cant be used, and go testing, and tuning. and have a AWESOME reliable EFI tuned boat.

Why is something like this not out there for mercs?

Your disagreeing with me based on what?

I just said converting to a custom EFI setup for a marine engine isn't as easy as people thinknor as cheap as people think, especially when you get into the big power stuff. Then you reply saying Im wrong, and then ask the questions you did.

I never said carbs are better. I love the stock injection systems on my cars.

Id love to sit here and recommend efi to everyone myself. But not everyone has the funds, nor the means, to run EFI in every application. Stock mercury power, heck yea. For the guy who wants to bolt some blowers on, or some aftermarket heads and cam, theres nothing wrong with bolting a carb on.

Some of the EFI cheerleaders make it sound as if, god forbid you have a carb!!! '' How on earth are you even gonna get any boating done! Youre gonna be stuck at the dock with your fouled plugs and burnt pistons!!! Is it even gonna start?''

No I don't mean the carbs wont work, I have had carbed boats before, they work fine as well.

BUT They are not involved with the right tools. WAY better, easier, and more reliable.

BUT I do agree the market for the tools is Bull ****.

a/f box is your best tool to use .you can tune both setup. carb and efi

MILD THUNDER ANGRY!!!!
GRRRRRR!!

:hothead: :violent-smiley-021: :blaster:

Bottom line.....The best tuned carb will never run as well as an EFI setup. Sure it takes a little time and effort to tune an EFI system, but whether it is 55 degrees out and dry or 95 and humid, that EFI system will still run mucho better. And it does not matter how big your cam is or what heads etc. Just get it tuned...

Ask our buddy how he liked his new cabs motors over his old efi !!!!! :poopoo:

I also agree it would be cost prohibitive to go to EFI from carb

But the original question was should he go from EFI to carb,,,,,absolutly not

I remember at the end of the year he had a issue when I was out with him. Starboard engine idled and ran like crap. I removed his flame arrestor, and had him restart it. Hmm, choke closed?? After a closer look, choke wire was off!! Reconnected it, vroom, idled like a dream. Cost him a beer. :thankyouthankyou:

LOL,,,,,,See,,,,,that would NEVER happen with EFI !!!!!!

Sorry,,,,,couldnt resist !!!

Wow,small world. I'm doing the exact same thing;upper hinge pin and seal. just pulled the drive and have most of the chit taken off the engine. I run a blown 540 with 1050 dominator. I purchased the boat with this setup and my humble opinion is if your selling the boat keep the fuel injection. Dont get me wrong, I love my carb setup but thats because I know how to tune it, I'm old school.I did own a newer boat with fuel injection before my current boat and I think for most people who dont know how to tinker on chit, then a turn key and go F.I. motor is what most people would want to buy. Now if your gonna keep it.....:party-smiley-004:

Also I dont know chit about tuning E.F.I.:poopoo:

I would stick with whatever you are most comfortable with. Lots of people manage to tune regardless of EFI or Carb. The difficult thing is to tune WELL. To do a GOOD tune, I don't consider one to be easier than the other. Just completely different methods. Prices vary widely for both systems, to do either correctly is going to take some money and tuning. If properly tuned, I assume in most cases the EFI will be a bit more efficient, but a properly tuned carb setup is not far behind.

In either case, if someone is uncomfortable with what they are doing, paying an expert to sort everything out, though expensive, is still cheaper than building 2 (or more) engines.

If you're selling, EFI all the way, and stock power holds value better than anything built.

Carbed Blown 540's. First startup after not being ran for weeks, 55 degree weather. Late october, with cold lake water. Engines didnt stall one time idling around, or hiccup. idle in gear like a dream.. :evilb:


[youtube]http://www.youtube.com/watch?v=2FTRhpGzRwY[/youtube]

EFI hands down. I've ran lots of carbed and EFI engines over the years. The only reason to go carb over efi is that its cheaper. EFI is infinitely more tunable than a carb. Especially if its setup to control ignition and fuel. Nowadays, buying anything with a carb would be a hard sell for me. Especially if someone ripped out a perfectly good EFI system to put a carb setup in it , I wouldn't touch it. Lord knows what other hack job they did on it.

Bottom line: you gotta pay to play with EFI

Mild
 

Its true that cig idles pretty damn nice for a carb. ..now if it had bravos and needed to idle closer to 800 rpm that might be a different story, a story I fortunately wont have to worry about.

Thanks for all the responses,
I am still not sure what direction I'm going in yet.
I do agree that efi is nice turn the key and go. I also agree that a carb motor is easier and cheaper to make horsepower modifications. Most of the guys I run with are running carbs and they never have problems. If the boat doesn't sell then I know that I want to get some more power out of it. Even though my intake is ported on my efi setup, I was told that with out putting a blower on it I'm about maxxed out what it will make for NA power. (Not sure if this is true or not). I am not crazy about doing a blower especially if I plan to sell the boat.

Maby it's just me but if there was 2 identical boats for sale, one with a 502 mpi and the other with a hp500, I would go for the carb hp500.
I am not saying that by putting a carb on my motor is going to make it a hp500 nor would I sell it saying it was a hp500 but the end result would be similar.
:party-smiley-004:

I wouild take a factory EFI 502 over a hoped up version as a buyer.

The better compassion is if one was a HP 500 and the other was a HP500EFI.

I am a old carb guy, but just don't see ripping out all the EFI to go to a carb.
If u were building your own motors and the boat was a carb boat I can understand.

Sounds like what u have isn't that bad.

This, Would chose the 500efi everytime, and pay more for it.

The Stock 502 Mag intake even ported is MAYBE good to 525hp. A set of aftermarket heads and a decent hyd roller cam, A dart single plane intake and a 850 holley will walk away from it. I know a guy who had a pair of 502 mags . He upgraded cams, installed brodix heads, intake and carb. When he went to sell it, he installed the stock intake/injection system, which was tuned for the mods. Boat lost more than a few MPH by going back to the stock mag intake/injection. But he also knew that 9 out of 10 people would pick the stock EFI over the carb, even if it made quite a bit less power.

Or do a setup like this from Holley. Maybe then you wont get labeled a ''Hack" ..it really is a nice setup though.

i have a bravo drive .i am running a 540dart with 718 hp . i idle at 800 http://www.youtube.com/watch?v=XKQj2fy91BU

Ok,,,,what rpm were the " ideling " at LOL !!!!!

Dan is greatful he doesnt have Bravos right about now !!!!