carb or not to carb
 

got a 302 boss with 454 mag mpi's i would like to put carbs on it because every time i turn around some little something is wrong with the mpi, either an injector a sensior or so on. I was broke down most all summer and just tired of it. I have talked to a couple different people and some say it's a good idea and some say its not, i am confussed and tired of not running right, WAT TO DO?

dont do it,,,, driveabilty, fuel economy, start up idle,,, resale will all go out the window.

I have changed many MPI/EFI motors to a carb because of the same reasons you have mentioned...always something going on. You need to ask yourself a few questions...

1. Are you tired of messing with it?
2. Are you ready to enjoy it...like at least drive it instead of looking at it on the trailer?
3. Do you REALLY care about MAYBE loosing 1 mile per gallonor having to fast idle it for 20 seconds when it is cold?
4. Did you buy the boat for yourself or someone else a few years from now when you decide to sell it.

If you answered YES to the questions...then toss the MPI/EFI out in the yard. If you do have an issue with a carb motor...it is either spark or fuel...not a bunch of electronic crap that ties a big knot around the motor. Install a good intake, 800 Holley, electric fuel pump and a MSD ignition system and you will be enjoying your boat anytime you want instead of sitting on the trailer all pissed off.

IF you can afford it, repower with a new or low hour 496 HO. Either option has pros and cons. When I bought my boat it had 615ci BBCs with a cutler fuel injection system. They never could get stbd engine to run right. I sold the FI system and put on a 1050 dominator, Dart intake and MSD ignition. The stbd engine melted down. It turns out the cam gear gear was rocking back and forth several degrees. Because I took away the computer, I also took away the safety net. After I rebuilt both motors (with carbs) it ran great for two seasons until I dropped a valve. Because one engine was destroyed, I repowered with 496s which cut almost 500 total horsepower from my 615s. Lost 10 mph. But I couldnt be happier because of the peace of mind (the safety net) I have with the efi. Bad gas? No problem. 87 octane? No problem. There's a lot to be said for correctly operating modern efi engines. BTW it still runs over 70mph with 2 people and 100 gal of fuel.

1 MPG ????,,,,, back in the day a buddy of mine and I had 27 foot baja's.... I had a 502 MPI,,,, he had a 502 carb.

we made the same trip, at the same speeds.

I used 33 gallons of fuel, he used 50 gallons.

Your 2000 has the cool fuel injection and is reliable as they get.

Find someone who knows efi to work on the boat, hook up a scan tool and fix it right the first time.

My guess is what you spend on the swap over would be more then you spend to fix your set up correctly.

Sounds like maybe the boat has had some bad care in the past and is just popping its head up now. ( improper fuel storage practices ,,, getting bad fuel etc. )

Things that would effect a carb motor as well

But if ya do change to carb,,,, crate up that efi crap and send it my way !!!!!!

that is one of my main problems there is no one were i live to work on the mpi i have to drag it 4 hrs to the closest people i trust and thay do a good job, it runs good for a day or two but after that here we go again. iv had the boat for 3 years now and been nothing but trouble, this year in the middle of the best time of the year a injector dumped to much fuel and burnt a piston so i got a new motor and got that fixed and its something else now. everybody makes good points but i just cant aford them 496 that i would love so much, and i answered yes to all the questions

I personally prefer the MPI because of the the better mileage, smooth performance through the full rpm range no matter how hard or easy you apply the throttle, never a hesitation, always starts right away when cold, you dont have to have it on high idle until it warms up for fear it might stall.
I think there is added hp with the mpi, didn't the 454 magnum carb's have 365 hp and the mpi have 385 hp, there may be more to?

I would look hard to find someone that is an expert with the system, if it cost to drive further also if you replaced all injectors fuel pumps and regulators, i would still think that it would be less money than carbs, intakes, fuel pumps, lines and linkage and ignition.

yea very good point, im just so ???? agravated right now im tring to get more peoples ideas and that was my next question if i was going to lose or gain hp iv always liked efi but these to 454's has changed my mind

These MPI guys make alot of good points, but if you have a problem w/ a carb motor while your out on the water, with a hand full of spare parts on board, you can fix it right then and there....and your boating day continues! Been there, done that.:grinser010:

A friend was having some issues, and it came down to the screens on the injectors had debris built up on them restricting the flow causing him all kinds of erratic conditions, he replaced them all and problem fixed.
But prior to finding the real problem he struggled with cleaning and replacing fuel lines, fuel pumps, and regulators.

From experience when you get some time on carb systems they can have issues also, rubber diaphragms in fuel pumps crack and loose pressure, same with accelerator pumps on the carb, not to mention debris in a jet or a float sticking.

When you get it fixed, I think it is critical to follow the proper winterizing of the fuel system.

I sent you a PM copenhagen419

I had the same problems with mine and I switched to a carb and could not be happier. I am actually able to enjoy my boat.I get better mileage now because my efi was in such bad shape. Cut your losses and enjoy your boat. No issues with with cold starts here either. Year and a half with no issues.

well thanks for the help with my decision guys but i think im going to have two 454 mag mpi injection systems for sale

If Mercury can squeeze 1300HP out of a big block (with a warranty) you should have NO problem getting your EFI'd 454 to run well, I have had both EFI and carbed boats, drag cars, sleds, etc. I personally would never own another carbed boat again

As for being able to "fix" a carbed motor with hand tools, well, if its maintained correctly you should never HAVE to fix a solid state EFI motor.

Good luck with whatever you decide, just my thoughts

Michael

Mercury got 1300 HP out of a BBC with the help of Mr. Whipple and there have been many issues with that motor...they sure as Hell didnt do it running straight up. Electronics and water do not play well together. You can go to any boat forum and start looking and there will be multiple posts of people with some sort of issue running a MPI/EFI...far more than people having issues with carbs. If you have a carb motor and you need to put a kit in the carb...no big deal...$50.00 and an hour and you are done. If you have a MPI/EFI motor and you have an issue...hang onto your butt...its gonna cost you big time. Maybe someday Mercury WILL get it all straightened out, but until then, I want to boat...in the boat on the water and not sit in my driveway and look at my boat sitting on the trailer wondering if I should drop another wad of money in it to fix it...again. If a MPI system works...great...more power to you, but when things start happening...the definition of a boat raises its head. B.O.A.T. = Break Out Another Thousand...nope...not me...I will wave as I ease on by.

I wasnt aware of any electronic issues with the 1300's? I know of a few guys with HP1075's and have YET to meet one who decided to change to a carbed set up

You cant BUY a Carbed car or truck, and haven't been able to for 20 plus years, pretty soon sleds, ATV's, bikes and boats will ALL be using EFI,

What do you for a tow vehicle? Have you considered putting a carb on it? Or maybe convert your wifes minivan to a carb to make it more "reliable" or "cheaper to fix"

I dont think anyone paying 100K for a motor that is EFI will be changing it to a carb anytime soon, but one can build a motor that is just as reliable as the 1075 or the 1300 with carbs for a lot less money. The 1300's that I have been told about go into the guardian mode for no reason or no reason found...true or not...I did not see it...just told about it. Mercury has sunk tons of money into their EFI program, but Mercury does not have the money to invest into it as do GM, Ford or Chrysler. Basically I see them on the second from the last tit. If your EFI system works with no issues...I am all for leaving it alone and run your motor as is. But I have seen too many go South after the first little problem...seems like it is one issue after another. The people that have gone to carbs after having countless problems with the EFI are finally getting to enjoy their boat on an everyday basis and are very happy.

As for my vehicle...I tow with an Avalanche. YUP..it is EFI, but is has never given me any problems...so I will leave it alone. But if it ever does...out comes the motor and in goes one with a carb on it and Al GORE can bite me for my carbon footprint. The vettes...one has a carb and one is EFI...again the EFI has never given a hint of an issue. Sorry, the wife does not have a mini van. She wanted an Altama so thats what I got her. Seems like the Japaneese has surpassed Mercury also...again...no issues with the Altama. Almost forgot...I also have a 08 GoldWing, but it too is Japaneese and EFI...works great and no issues. If my scooter startrs giving me trouble, I can order the parts and make it a Valkery GoldWing. Got a few friends with Harleys and even Harley has their act together over Mercrury...no issues.

As for not being able to buy a car or truck with a carb in the past 20 years...sure you can. Car lots are full of them. It might not be new, but it will be new to whoever buys one. If I get another boat with EFI/MPI and I decide that I dont like it...off it comes...again AL GORE...bite me. If your EFI/MPI is working and not giving you any problems...I agree...by all means...leave it alone and enjoy your whatever ride. But in the same breath, if it starts giving you problems, it is going to be endless and all one has to do is start asking people about theire problems with EFI. When they respond, it usually starts out with the mighty "F" word.

Sometimes things just get old and break, it does not always have to do with proper maintenance. When things do break it is really hard to find someone competent enough to fix all of those wonderful efi issues. Yes it can be fixed, but it takes lots of time lots of money and lots of frustration. I personally would rather not waste time or money chasing down those issues. As for resale value a boat with a carb is worth a lot more than a boat that does not run.

Dont sell your efi right away. I would hang on to it, that way you have something to go back to should you decide that the carbs are not working out for you.

Does he need a new wiring harness when the change is made?

No...he will not need another harness. The best thing to do is to unplug all the connections that will not be used and just tie them up out of the way. The only wire that is needed for the MSD distributor is the ignition wire HOT when the key is turned on. All the other stuff on the stock distributor is just there...tie it up out of the way. You do not want to cut anything because some of the connections are looped around together and if you cut the wires off, you have killed the loop...and you might need it.

Point Taken, and valid points the are, I appreciate your opinion!


Oh, I agree! Those 1075's aint cheap, then again, price a 1100HP motor from Stellings or Teague and see what it costs. You are correct you CAN build a motor that makes the same power for less money, however, will that motor idle through "no wake zones" without loading up? or be "tame" enough to back in and out of a crowded Marina and a second later rev to 6K without missing a beat?

Carbs work very well, they where around for a LONG, LONG, time and have been designed and re designed to the point of being almost perfect, but, they do have limits and I think we have reached them. In many cases people like to stay with "what they know". I am a 3rd generation drag racer and I remember my Father/Grandfather talking one day about the HUGE uproar when "Electronic" ignitions came out, I remember my Father telling me that he had good friends/fellow racers that where DAMN good at turning wrenches who swore it was a fad and would NEVER use anything but points ignition, ironically, the reasons where very similiar to why people dont like EFI set ups now.

But, when was the last time you seen a points ignition on a vehicle? To be honest, the points set up does work, and for the most part, worked well, but, it had limits, and needed to be replaced by something that was arguably "better".

I too am a "vette" guy, the oldest one being a 63 split window [sadly, it was a small block, with points! lol] and the newest being an early 90's ZR1 which I loved until I realized I couldn't afford to pay for it, as well as pay for insurance and gas [ouch!]

Given the choice to drive either one for an hour I would take the 63 hands down, but, picking one to drive to Florida and back without fear of breaking down? I would have to lean towards the ZR1.

In Any form of motorsports thats allows them, EFI motors are usually the quickest, ask any competitive NHRA Pro Stock or Winston Cup wrench if they would like to see fuel injection allowed, and they will usually start drooling at the thought.

I agree, that it IS easy to fix a carb or carbed motor, but, there is also someting to be said for being able to just plug in a "scan tool" and in 15 seconds having the probllem diagnosed.

I look at it like this: Carbs where around forever, and where very dominant, but, the same can be said for dinosaurs.

I have no problem with Carb stuff, and still get wood at the site of a pair of split doms on top of a sheet metal intake, but, I think that other than in a handfull of cases, Fuel Injection is going to slowly phase out carbs. It seems to a natural progression, kinda like records-cassettes-cds-mp3's and whatever comes next, LOL

If your carbed stuff works for you, then Great! as you say enjoy it every weekend and have a blast, after all, thats what we are "in this" for, Its just a matter of opinions and both are viable options

Have Fun!
Michael

Well said.

In time the marine industry will be exposed to another more advanced fuel delivery system, and people will question it and if possible steer clear due to lack of understanding.

Points well said. I gues...for me...I am too old to have any desire to learn the EFI/MPI stuff and you are right...I, like others stick to what I know. I will admit...I dont know squat about the EFI/MPI...mainly because I have no desire to learn it and almost all I have dealt with in the marine world has been wounded and not working correctly. I also had a 63 vette when I was a junior in high school and 17 years old. it was a saddle brown, 4 speed with 4:11 rear end and the 327 fuelie motor. I sold that car to my history teacher in my senior year of high school and he still has it at his age...82. Told me that when he croaks...I can have it back. My carb vette is a 72 ( http://shooteraod.dyndns.org/72vette )...this is what it looks like after 7-1/2 years or restoring. This car is a numbers correct car.

I did the drag racing thing too...loved it but decided that I was going to kill myself if I didnt stop, so I quit. I still go to the races, but I only watch or help friends.

Got friends running 1200 and 1300 HP motors out here and they are carbs. They dont load up but they sure sound good packing that air. I think the reason my carb stuff works great is because I dont mess with them every time I go out. I just turn on the key...wait a few seconds and pump them 2 or 3 times...then hit the key and the motors fire right up. I think the people that have issues with the carbs is because they seem to think that they need to adjust them all the time. I tell people to set it...then keep your hands off of it. This might be true with some and EFI motors as well...I just know enough about one to know better then to mess with it.

Whatever works best for someone is the way to go...cheers.

""In time the marine industry will be exposed to another more advanced fuel delivery system, and people will question it and if possible steer clear due to lack of understanding. ""

I bet that this will be the truth.

Michael,
I agree with you 100%, but the problem with the MPI/EFI stuff is that the equipment needed to work on it and modify it is ridiculously expensive, to the point of being unaffordable for the average (or even above average) garage mechanic, and the cost of paying someone to work on it, IMO currently outweighs the reliability/efficiency benefits.

Here is a comparison - TPI stuff use to be impossible to work on, to the point where you HAD to buy certain camshafts that would work with the computer to get them to run right. Now anyone willing to spend $1,500 on a program and cable can hack a TPI computer with a laptop, re-program it, alter it, and do all of the modification yourself, in your garage. In the early 90's, for whatever reason, the car manufacturers didn't want to let the technology out to the public. Now it is readily available, simple to use, and relatively inexpensive.

I don't know what they charge for the computer systems that reflash ECUs, but I bet its a LOT more than $1,500 and on top of that the technology is much more secretive right now. When that cost comes down I'm sure that many more people will be willing to keep MPI/EFI systems, and more people will want to switch to them.

I was going to make the switch from carb TO MPI myself, but decided against it, as I like to tinker too much to get more Hp out of my stuff, and I don't want to have to send the ECU to BFE every time I make a change. On top of that, I'm not confident that they're getting everything out of my motor when they're programming the ECU from a hundred miles away, and basing the ECU changes off of what I'm telling them that I did to my motors.

When I can work on my stuff at my marina with my tools I will likely make the switch. I'm even willing to over-pay by thousands to get the technology to do so, but I'm not willing to over-pay by tens of thousands, and that's whats stopping me right now. I'm sure that many boat owners are in the same position or feel the same way that I do about the subject.

If interested there are products out there to program ranging from $595 to $1,895 depending on how far you want to go, I have not used these yet but am exploring the idea, I am sure there are folks on here that would be very glad to assist in product info and how to use.

http://www.mefiburn.com/