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2005 50 mpi bravo 3 drive computer question

rsigillito

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"I am new to sterndrives and t

"I am new to sterndrives and to this forum. I always had smaller boats with outboards before. I appreciate any help you can give me.

I am repowering a 24 ft aluminum flat bottom shrimp boat to use for leisure fishing. It previously had an old early 1970's era 351 windsor mercruiser engine; drive was long gone.

I found a 2005 5.0 mpi that a person had (partially)installed in a four winns with an old m/r drive that he said he ran once but the drive was knocking so he never put it back in the water, engine was never broken in. I don't think the engine was ever properly installed (merc support line rep said a 2005 5.0 MPI could not be run with an old MR drive)

I also found a 2004 bravo 3 (2.2 ratio) that was on a boat that the owner blew his 5.7 ltr engine. The drive had such little use that the paper barcode/price stickers are still on it. I pulled the drive (with props), gimbal housing, inside transom mount/ steering components (except the hydraulic pump which was already taken) off of the boat over the weekend.

I called mercruiser support today to get some information about drive compatability, & what I would need to get started. The rep told me I would need to buy a new computer for the engine that would be compatible with the bravo drive, and that the engine would need "a laundry list of parts" to make it compatable.

Is this correct? Are there really different computers for 5.0 MPI engines using alpha vs bravo drives? Or can a computer be "reprogrammed" for a different drive? Can I tell from the engine serial # what type of computer / drive it was set up to be used with? Prices on both the engine and drive were very reasonable}, so I can afford (I hope) to remedy the problem and still come out ahead - I just need to know if I should be looking to reprogram; or instead for a different computer to run with the B3; or if I need to leave the engine as is and find an alpha drive.

I appreciate your help with this. I have a mechanic installing the engine & drive - his opinion is that we should put the engine/drive together on a test stand and see how it runs, then address any problems we encounter."
 
"[b]Is this correct?[/b]

Ay


"Is this correct?

Ayuh,... That's Right...

Bravos,+ alphas shift differently,+ the 'puters are Not reprogramable..."
 
"Ok, engine is out of the old

"Ok, engine is out of the old boat, and it is a 5.0 alpha. I see that I'll need a bravo type engine coupler. Sounds like a bravo-version computer also.

I have to get new cables and controls anyway, b/c the old ones (from both boats) were trash. Will that take care of the different shifting issues? Is the wiring harness different btwn the alpha and bravo engines?

The wishbone exhaust is a correct style and fits the bravo 3. (It was bolted to the MR drive with only 3 bolts b/c the bolt patterns didn't match, but it doesn't look damaged in any way.

The oil reservoir that sits next to the oil filter (I think it is for the drive oil) is missing, I guess they took it off b/c of the MR drive. It will have to be replaced. I think there must be some kind of a low oil sensor missing also.

Is there anything else that I will need for the engine to "convert" it to a 5.0 bravo?

Thanks again"
 
"I guess I should have added t

"I guess I should have added that I need to figure out what would be better: to buy an alpha drive, or to press on with a conversion. From what I've read and from speaking with other people, it sounds like the bravo drives are a big step up. But I don't know anyone who actually is running one. Your opinion would be greatly appreciated"
 
"Just my own opinion - stick w

"Just my own opinion - stick with the alpha.
Most Bravo's (and I assume you are talking about a single prop Bravo 1) are sold on higher HP applications - the alpha is good up to 300 HP.
You will save some weight and installation ease with the Alpha, not have to drill two more holes in the transom, and with proper care and maintenance last a good long while. Option two -
SEI (Stern drive engineering)makes Alpha replacements for a goood price and some others have reported they were very satisfied with the product."
 
"G-Day Robert,

You don'


"G-Day Robert,

You don't need a computer to suit the outdrive. All the computer does is look after fuel management and spark advance. Also, they can be reprogrammed. Check out http://www.mefiburn.com/

The Bravo 1 is the best bet. Solid, easy to service and a better shift than the Alpha. Bravo 2 is big and heavy, very limited range of props to suit, ideal for work boats, house boats, 400HP and up."
 
"I already have the bravo 3 wi

"I already have the bravo 3 with 2.2 ratio and both props, and all of the gimbal housing/transom mounts. It was a very good price so I didn't pass it up. The mercruiser site says it will handle up to 400 hp. The mechanic mounted it on a test stand today and and says the coupler that came with the engine fits fine, and that the shift cables all hooked up without problems. So tommorrow we'll hopefully get it started up on the stand.

according to the merc site, the bravo 3 adds only 67 pounds over the alpha. Thats not too much considering the bravo 3 seems to be such a bullet proof drive"
 
"Does your engine have a sea w

"Does your engine have a sea water pump? If not, you'll need one and of course a new serpentine belt as the Alpha drive had the pump in the drive itself where Bravo does not.
Also, the Alpha and Bravo models are different in ECM programming and unless you have a really friendly authorized Mercruiser tech. who may be able to re-program, you'll need to buy the correct ECM.
(Btw, be aware they are also different depending on the cooling system)"
 
"We have the engine and B3 dri

"We have the engine and B3 drive mounted on a test stand. We have a bolt on sea water pump installed (had to custom make a bracket.) As far as I can tell, the ECM alpha/bravo sensor differences include a momentary shift interrupt for the alpha that is not used on the bravo (It doesn't seem to hurt the bravo to use it with an alpha type interrupt; but I think there would be a problem using a bravo engine - no interrupt - with an alpha drive); and a gear ratio indicator switch that has to be reset. Otherwise, according to the scanner, the alpha and bravo settings appear to be the same. The shift/cables also fit under the coupler without a problem (apparently this was an issue for some engines, but works fine on mine). So far, fingers crossed, everything is working - but I wouldn't be surprised if the fuel management issues will require some reprogramming. I can't do it, but the tech installing the engine can do it with his computer (there is a program out there that lets you modify the settings.)

I hope to get the hull back from the welder next week, so I'll post again when the engine is in/runiing and it goes through a real trial."
 
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