Carb vs efi? New purchase insite-gctid817263

[businessgetmoney]

Hey guys, im looking at getting a new boat. Its not a bayliner, but im asking about general tech things...

Boats a 2001 formula pc 31 has twin 454 efi mercs with bravo 3 drives kohlsr 7.5kw gen set, heat and ac.

Engines and gen set need rebuilt. Could switch to carbed setup.

Always been curious of efi vs carb benifits. Obviously carbs being mechanical less work and expense of maintenance, ability to rig in field if broke down (simplicity). Obviously efi less finicky smoother running more user friendly at pocket book expense.

-fuel economy worth it?

-what else to consider here?

Additionally what else do you think i should be looking out for woth the heat and ac systems being that this boat has lost engines? Never had a boat with ac, dont know anything about the "reverse cycle" ac systems or whatsver they are called..

This is a good start, give me some input advice! Thanks guys.

[6104696]

Back in the 80's and 90's when EFI started to take over the automotive world, I hated the concept. Then, one by one as I was forced into EFI cars.....I became a convert but was unsure how the tech would perform in a marine environment. Now that I have had EFI boats for over a decade........if I never see a carb again that is fine with me. Easy starting, great reliability....and the technology, though computer dependent, is not as complicated as you might think. MPI uses a pressurized fuel rail, and the injectors are little more than solenoids. A few sensors (which seem pretty reliable when compared to carb problems) and two throttle bodies (a big one that responds to your throttle inputs and a small one (Idle air controller) that "automatically" adjusts for idle speed.

The biggest source of failures that I see or have heard about are injector failures and idle air controller failures, but they are just not that common. For me it's EFI all the way. Even the "throttle body injection" systems, to the extent that they are still used, is much more reliable than a carb.

[mister_larry]

Although they have more technology, the EFI system may be the least expensive to keep and/or rebuild along with the engines. I'm not completely familiar with the 2001 set-up but it wouldn't surprise me if your EFI system operates on different fuel pressure than a conventionally aspirated engine. Those fuel-rail designs can contain more pressure, and deliver it directly to the combustion chamber without risking the DEADLY fuel leak. There would be no way to run a carbureted engine at those fuel pressures. So to change to carbs would mean to change the entire delivery system.

As for the AC, those of us in the northwest don't even know how to spell it . . . What a luxury.

Happy boating

[green650]

Assume all those other systems don't work, unless you can test them. What is the condition of the wiring harness, manifolds, etc?

It is much more expensive to purchase a complete new 454 MPI versus one with a carb.

I hope you are getting the boat for free, sounds neglected and like it needs upwards of $30,000 in work, much more if the drives are toast.

[aluxury1]

There is nothing to gain IMHO going back to the carbs. Economy nad power will be better. Try sticking with non ethenol fuel. And as far as A/C goes, when its as warm as it gets in the PNW, its just right. If you want A/C, get a room. :lol:

[Ruffryder]

that is a very nice boat!

everything in life is a compromise...they both have their own advantages.

[businessgetmoney]

Im really curious what caused the engines to go and why it was not an insurance claim..

The guy who is selling is not the one who lost the engines. Ive experienced a boat with issues and no previous owner to cover what the real deal is and its been a nightmare. I swore i would never do it again, but this boat i would be getting on trade work and in a sense i would have $0 getting into it and plan on a heafty 15-20k for engines and such.

I will say if here is anything beyond new engines im not interested. Dont want to chase down hull leaks or a rotted interior or bad canvas... let alone bad tansomes or whatever. its not worth it, becUse for half the price i can get a 95' that has new engines and drives canvas and been owned last 15 years all kinks worked out.

The appeal is trade work for boat and a winter project and being in it for 20k and ending up with a 50k boat... maybe thats just a dream, but best educated guess is all im shooting for now.

Thanks all.

[Download_Complete]

1. This is a high end boat, and 2001 is around the time high end makers went to all EFI. For resale alone, I would put EFIs in.

2. Carbs are not simpler and "easier". Carbs are mechanical, more finicky, and more failure prone than EFI. When was the last time you had an EFI issue in your car? Exactly. You can swap a fuel injector out with a screw driver and 15 minutes. Carbs have multiple "failure modes", and I have lost more boating time to a mis-adjusted carb than I ever did to anything else.

Carbs are dead, and good blanking riddance.

3. EFI is easier to start, easier to diagnose, more powerful, more fuel efficient.....

EFI. EVERY time.

[Norton_Rider]

"mister larry" post=817290 wrote:
Those fuel-rail designs can contain more pressure, and deliver it directly to the combustion chamber without risking the DEADLY fuel leak.

The systems with a fuel rail are commonly referred to as Multi Point Fuel Injection or Multi Port Fuel Injection, MPFI. They do not deliver fuel directly to the combustion chamber. Instead, they deliver fuel right outside of each cylinder's intake port. They run at a higher pressure than carbureted systems because the injectors need it to properly deliver and atomize the fuel.

Direct Injection (DI) systems deliver fuel directly to the combustion chambers. This is common in diesel engines. They are not that common in gasoline engines, but are slowly becoming more popular. As a matter of fact, a number of outboard engines now have DI systems. These systems run at very high pressures.

I would definitely opt for EFI engines on a boat.

[businessgetmoney]

Really appreciate the feedback.

Sounds like efi is not so bad after all.

[6104696]

This is not an answer to a question that you asked, but I will caution you that "free" boats are usually the most expensive boats on the face of the earth.

Jus' sayin'.....

[Download_Complete]

"businessgetmoney" post=817958 wrote:
Really appreciate the feedback.

Sounds like efi is not so bad after all.

If EFI was bad, we wouldn't have it in cars. With the new variable valve timing like in the new Volvo Penta V8s, fuel injection isn't just a nice to have....it's a necessity.

Anyone who cautions you to stay away from EFI is likely just afraid of technology. Again, EFI is a proven technology and has been in boats now for going on 20 years. It's time to stop being afraid of it.

[businessgetmoney]

Saw the boat today, couldnt walk away fast enough... and actually my brother said the same thing!!

Wish the guy told me it was a salt water boat! I wouldnt have wasted a 4 hour drive

The entire engine bilge looked to of been flooded to top of engines at least, absolutely everything down there was junk. Every mount bracket rusted, every wire toast all electronics no chance. 60k in there alone to start! Wth was this guy thinking... i told him even for free i wouldnt take it

Then theres the drives... toast! Not a chance they were good, the exhaust hubs 80% filled with barnicles, boots rotted, sensor wires ripped out annodes gone trim rams pitted..

The hull had 1/4" of paint on the bottom from the years of brack water protection.. my god what a nightmare. Throw it away, stop paying storage

[businessgetmoney]

Pretty upset i had my heart set on it.. if everything was right i could have those engines rebuilt and running for under 10k.. maybe be in it for 15k and 3 weeks of my labor for the trade... not bad for a 50-60k boat. Give me something to do this winter.

There will be another, just going to have to pay cold hard cash for it.

[88fourwinns]

We would all agree that EFI is better for starting and consistency in running; just as it has been in cars. My one caution is if you are considering an old one make sure certain parts like ECMs, fuel pumps and injectors are still available. Because if not and you have a failure then you will be SOL!

With carbed boats you can always get a re man or new carb and fuel pump. Nothing there can really hang up up....