MPI vs. Carb...

[andy1canada]

Howdy from Canada!

Hope some of you folks might give me some useful opinions...

I've just bought an older glass boat and am about to repower her. I'm taking my mechanics advise and going with an all new Merc. sterndrive. I'm not interested in adding a POD with some monster outboard hangin' off it.

The boat is a 19/ft. Zeta (1980) cuddy that weighs in at 3000/lbs empty with the old 188/Merc sterndrive (302).
(These were built in Vancouver from 72' into the 80's and still have an excellent reputation as an extremely well built hull.)

Here's my problem: I've been reading about the newer MPI Mercruiser's and although they are more expensive than the carb'ed units they obviously have some advantages. I've more or less settled on another small block V8 (vs. the 4.3) so my focus is on the 350. Yet my mechanic is encouraging me to stick with the carburetted version for the sake of simplicity/reliability. He's given me much sage advise thus far and I won't dismiss him.

How many of you have had problems with the Merc/MPI system? What's the track record of these fuel systems so far?

Any and all help greatly appreciated!
Cheers,
Terry

 

[HT32BSX115]

Re: MPI vs. Carb...

I am doing the same thing and chose the carb'ed BBC because it was a good deal and came along at the right time.

I think the carbed models are simpler but I don't hear about a LOT of problems with the EFI units either.


My 1st choice was for a BBC MPI. but none presented them selves for the right price. (I paid $5k for this one...steering wheel to props 122 hrs since new........pretty hard to pass up)

Also I can always trick this engine down the road and not have to worry about reflashing the eeprom, or changing the injectors etc.

Or just swap it out for something much bigger! many choices!



Regards,

Rick

 

[marinemech1]

Re: MPI vs. Carb...

Hi: if it was me I would go for the mpi version
reason G.M. (they make the engines for mercruiser) do not make carberated motors any more, therefore all their r&d is with efi engines. also i have heard that when they went all efi they bumped up the compresion ratio.

 

[andy1canada]

Re: MPI vs. Carb...

Thanks for the replies guy's!

Regardless that land-based engine technology has basically done away with carb's, does that really mean injection is the cat's-a.. for boats?

More things to break while you're out on the water?

Can't call a cab if you break down... or take a bus.

Okay, okay... injection equals easier starting, somewhat improved fuel economy and accelleration; but I can buy a lot of gas for the extra cost of an injected setup and surely, if the day arrives that I decide I need more poop out of the 350 well - what the hey - throw me on one of them there Eldebrock manifolds n' one a dem' der' four-banger Holley's and presto - she's a fire-breathin' small block!

Any more taker's out there in favor of MPI?

Cheers,
Terry

 

[HT32BSX115]

MPI vs. Carb...

I don't think anyone is suggesting that it would be cost effective to change a carb engine to EFI.

It costs a fortune to buy a system that would replace a carb. You're much better off just replacing or finding an engine with EFI. (but that's not cheep either)

I think you'll find that the Mercruiser service guys on here will probably tell you that with normal maintenance the EFI engines are absolutely reliable.

Last summer I sold my Dads 1966 Mark Twain that he bought new (I was 13 when we got it)


It had a GM inline 6 (150hp, Mercruiser #1 drive) The head had never been off and I replaced the coupler in 2005 (it had never been replaced either)

It had a carb on it. I don't think he EVER put a carb kit in it. I know I didn't and I had it from 1997 - 2006. (he only replaced the raw water pump once!! in the 80's I think....I replaced it in 1997 when it started to over heat at idle)


I guess my point is that if you take care of it the carb can be pretty reliable too.....but far easier & cheaper to fix when it breaks


Good luck finding what you want!


Rick

 

[QC]

Re: MPI vs. Carb...

Andy,

Saw your other post on the other MPI thread . . . EFI and MPI have been around with Merc since the early 90s. For the money, I think I would consider the 5.0 MPI with 260 bhp at the Propshaft and unless it was significantly less money I wouldn't consider a carbed 5.7. This is more bhp than almost all stock carbed 5.7s in existence and more than the 250 bhp available today.

Personally, I would not stress about "peak" torque, it is important only for hole shot and has nothing to do with top speed, and I bet the 5.0 has more than the carbed 5.7 anyway. If the boat planed as it was (I am sure it did) this setup will blow the old away as it probably made less than 200 at the propshaft back then.

BTW, welcome to iboats!!

 

[Tail_Gunner]

Re: MPI vs. Carb...

EFI is a far less troublesome system than a carbed system anyday, I am not busting on carb's by any mean's here, but i can tell you going back to the auto ind. they almost require yearly maintance, if it's not a choke system it's a float or a fuel filter or a linkage etc. etc. etc. not even going to mention how many motor's get abused by cranking them up for a minute or two trying to get them to start or how many get there oil contaminated from a over rich setup.

EFI may not be as easy to manipulate or do a quick repair or fix , but i believe they are far more reliable and stable. But what the factories charge for the diagnostic software is outrageous so if your local mechanic dosnt like them, that could be a real reason. Just a opinion your milage may vary........

 

[gmctodd]

Re: MPI vs. Carb...

Hey Andy,

I believe my dilema is solved.Liked the MPI idea from the start, just needed to find a way to justify it to myself. Just gave the dealer a deposit on a 2007 Crownline 200LS ponied up the extra and got the 5.0L MPI Merc. the largest horsepower motor offered in this model( The 5.7l is offered only in carb) Now the long wait till it finally arives! Thanks to everybody for your comments and opinions, they are all appreciated. Good Luck Andy and Happy Boating All.

Todd

 

[andy1canada]

Re: MPI vs. Carb...

Hey Todd!

You might want to recheck your source on MPI availabity.
You can get a 350/MPI from Merc. It'll cost you about $1500.00 or so more clams though. That said, both packages (engine and drive) weigh in at about 950/lbs and the 350 will churn about another 40 horses.

I'm now set on the 4.3/MPI. I've done my homework and am convinced it's the right choice for my new (old) boat. This little injected powerhouse weighs in at a hundred pounds less than the V-8's and puts out about the same horses as the carb'ed 305, and about 30 more than the old 302 Ford that now resides in my boat. I figure if the styrofoam in the old girl ain't too waterlogged (in which case she'll get a good douch'in) the 4.3 should push her in the low to mid 50's. That's plenty fast enough for me on the chuck; logs appear out of nowhere at those speeds... and you also spill more beer. Not good!

I made my decision on the 4.3 after reading test data posted on the Mercury Marine website. There's some very useful stuff posted there for anyone considering/weighing any of the new Mercruiser packages. They've posted test results on various new engine/boat packages. Most of the engines are tested in several different boats and the performance and economy results are all posted.

Some of the test boats don't their weights posted but all have the Model and length info and it's a simple coupla' clicks to go to the manufacturer's website to find the weight of any particular boat.

Go to Mercury Marine's website then click your way through to the sterndrive page. It's all there...

Cheers,
Terry Anderson

Victoria, BC
Canada

 

[180shabah]

Re: MPI vs. Carb...

When looking at weight, power, and economy those 4.3's are great engines. I think you'll be very happy with the results.

 

[Haut Medoc]

Re: MPI vs. Carb...

Why not buy a brand new 351 from ebasic power for $3500.00?
Unless you are planning on replacing the entire drive system....

 

[gmctodd]

Re: MPI vs. Carb...

Hey Andy,
I understand that there is a larger V8 MPI available from Merc. It's just not available in the model (Crownline 200LS) that I am purchasing. I too believe that the 4.3 is a well built powerhouse. ( I have a 91 S-10 Blazer with just about 300,000 miles on it ) and was beginning to wonder if I could have saved a couple grand. But based on the opinions of others I have spoken to that have the same boat, if they would do it again they would have elected for the larger powerplant.

Todd
-----------------------------------------------------
05 GMC 2500HD
06 GMC Envoy
07 Crownline 200LS - 5.0 MPI
02 Keystone Sprinter 299RLS

 

[andy1canada]

Re: MPI vs. Carb...

Hey Todd!

Sounds to me like you've taken the plunge and bought the Crownline. Congrats! I'm sure you'll enjoy it.

I hear what you're sayin' about the 'should'a bought'a bigger engine' thing...

Hard to argue against more horses and torque. But one should also stay front and center about exactly what they want their boat to do. Right? My last boat - an 18/ft. 1971 Fiberform open runabout (140/Mercruiser) could do better than 40mph... that was plenty fast enough for me back then, considering the rough water we often deal with here on the South Coast of BC. As I mentioned in an earlier post, we often have an abundance of driftwood and stray logs floatin' around here and with the 4.3 MPI in my next boat, them there logs will be coming at me at over 50...

Eye's ahead, one hand on the wheel, the other on the throttle... suck on yer' beer through a long plastic tube and don't run over any Killer Whales...

Enjoy your new boat!
Cheers,
Terry

Victoria, BC
Vancouver Island