copenhagen419

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?

obnoxus

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

pslonaker

iTrader: (1)

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.

sandcraft

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.

obnoxus

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 !!!!!!

copenhagen419

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

JWoolever

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.

copenhagen419

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

kreed

iTrader: (2)

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.

JWoolever

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.