Bravo one lower unit need help.

[bolo78910]

Hello again everyone, I have a little problem and need your help. I need some info on how to take apart the lower gearcase from a bravo one outdrive that hit something and damage. Am planning to perchase a new lower from Sei.

What gear should the drive be in doing this ..
Should i get the lower gearcase with dual water intake or single.

Been as how the lower gear case hit an under water obstruction the prop did not hit only the front off the bullet,. Put a big crack in it, oil is running out.
Does that means the upper is shot also?

Last how do I check the upper for damage, I don't want to perchase a lower gearcase and the upper is no good.

Thanks for any info. Also are there an online manual on this drive. God bless

 

[alldodge]

Since your plan is to replace the lower don't bother with disassembly. Just remove the bolts and nuts holding the lower half and separate the two halves. Next remove the top off the upper section and look at the gears. If you see water your going to need to take the upper apart to clean, lube and check for damage.

How much did you run the drive after the impact?

So far as which type of pickup, they all work, the dual water pick up is nice but not necessary for the regular boater. It also requires different muffs to plug the forward hole. Use it if you like but as before your will be fine without.

SEI does not make the Bravo drive, only the Alpha

As for the ratio, see if it is marked on the side. If its not there what type and size boat is this?

 

[Bt Doctur]

http://www.boatfix.com/merc/Servmanl/11/11b3r5x.pdf

 

[thumpar]

Since your plan is to replace the lower don't bother with disassembly. Just remove the bolts and nuts holding the lower half and separate the two halves. Next remove the top off the upper section and look at the gears. If you see water your going to need to take the upper apart to clean, lube and check for damage.

How much did you run the drive after the impact?

So far as which type of pickup, they all work, the dual water pick up is nice but not necessary for the regular boater. It also requires different muffs to plug the forward hole. Use it if you like but as before your will be fine without.

SEI does not make the Bravo drive, only the Alpha

As for the ratio, see if it is marked on the side. If its not there what type and size boat is this?

SEI does sell the Bravo 1 lower just not the upper.

 

[bolo78910]

Thanks guys very much,. Alldodge Sei now sells the lower gearcase for the bravo part number #se 121 and se 122 if u want the dual water intake or so single. Bt doctor thank for the link. The boat is s 92 sea ray 270 weekender. So when am taking apart the lower just leave it in neutral re install the new part with new gaskets do a pressure test and done. ??

 

[alldodge]

So when am taking apart the lower just leave it in neutral re install the new part with new gaskets do a pressure test and done. ??

Yes, there is no reason to put the shifter in gear, normal is neutral position.

Being a 92 and a 27 footer, I'm guessing you have a 7.4, if that's the case you will probably have a 2:0, but that's a guess.

 

[bolo78910]

Yes it is a bravo outdrive, thanks. I will post my finds.

 

[bolo78910]

No Title

Update here guys . It turns out i dont have a bravo one it might be a bravo 2,. Am about to buy a lower half but want to make sure. This is the pic of the one i have .

 

[alldodge]

Yes that looks like a B2, prop diameter should be around 21 to 23 inches, a B1 is in the 14 to 15 inch area

 

[muskyfins]

My Bravo 2 had an 18" prop (23P)

The measurement to take is from the prop shaft center to the anti cav plate.........but I can't recall what it should be for B2.....maybe someone can chime in

 

[bolo78910]

Thanks alldodge ,. So the lower gearcase ratio does dosent matter.

 

[alldodge]

The sell comment isn't a good thing to do here, but there are different ratios for B2

Ratio	Drive	Driven
2.20	23	30
2.00	27	32
1.81	27	29

 

[alldodge]

Oh and also you can change the B2 to a B3, but then your also going to need more props

 

[thumpar]

The uppers on the B1, 2 and 3 are the same except for ratios. I would probably go for a B3 if you can find a good deal.

 

[bolo78910]

Thanks guys , the b3 would be a great idea but too expensive,. So when i have my alpha one drive i was told the gear ratio only matters in the upper. Is it diffrent frome the bravo one bravo 2 ?? Tomoro i will take off the top and count the teeth to see what gear ratio is in the upper.

 

[alldodge]

The bravo uses both upper and lower sets to make the final ratio. Here is the B1 and 3

 

[bolo78910]

update here guys, well it turns out the drive did get some water in it, after taking off the top caps some off those small bearing has rust. the large gears has no rust. after spaying some wd on it and pour some gear lube all ove them, the shaft stat turning freely. but am going to dump it and get a complete unit.

now my last ?? before i close this thread . been as how the boat came with a bravo two , will a bravo one do the same job ??? thanks yall.

 

[alldodge]

will a bravo one do the same job ???

No, the B1 is great for lighter boats single engine boats, yours is heavier boat and this is the reason for the B2. The B2 was also used because the B3 was not available at the time. So IMO you need a B2 or B3 but not a B1

 

[thumpar]

With a boat that size and weight you need more bite than a b1 gives. The b2 throws a bigger diameter prop and the b3 throws twin props. I would pick the b3 first. It may be hard to find a deal on a b2 just because there are not as many out there.

 

[bolo78910]

Ok thanks much guys i almost bought a bravo one omg thanks. This is the serial number for this drive hope someone can tell me the ratio. OD770681. Dont want to get a drive with the wrong ratio. Thanks again.