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new motor question

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sterlin318

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I recently purchased a boat for parts for one i had, ended up it will turn out to be a better boat so i decided to replace the floor, and the 4.3 block was cracked when i bought it. So i bought a 5.0L mercruiser to put in it. the out drive bellows were rotted so i pulled it off to replace them. it has a Bravo 1 out drive and now my question is, with the 5.0L and the bravo 1 that was mated with a 4.3 will gearing be an issue? and I dont know much about it but i know the intake cover for the 5.0l said alpha not bravo. will this make a difference? :confused:
 
Bravo has a raw water pump on a belt engine mounted.

Alpha has the raw water pump in the drive.

The way i read your post you have a 5.0l with a drive that is a 4.3l if i am correct you will probably be ok.

You may have to adjust prop pitch maybe not... what does it say on the valve cover for recommended rpm at wot ?

You can't exceed that understand ?

Thats where the prop comes in less pitch faster turning prop, more pitch slows down the prop.
 
Master mechanic said:
Bravo has a raw water pump on a belt engine mounted.

Alpha has the raw water pump in the drive.

The way i read your post you have a 5.0l with a drive that is a 4.3l if i am correct you will probably be ok.

You may have to adjust prop pitch maybe not... what does it say on the valve cover for recommended rpm at wot ?

You can't exceed that understand ?

Thats where the prop comes in less pitch faster turning prop, more pitch slows down the prop.
Click to expand...

Thanks for your reply!

The WOT RPM range on the 5.0l is 4400 - 4600 and the 4.3 is 4400 - 4800

and as far as the water pump i can just get a belt driven pump and mount it and should be fine?
 
sterlin318 said:
and as far as the water pump i can just get a belt driven pump and mount it and should be fine?
Click to expand...
Belt driven sea water pumps often cause an owner to defer impeller maintenance due to the difficulty in accessing the impeller. The belt must be loosened and removed, the pump must be removed from it's mounting, and the impeller R&R is typically done on the work bench.

If you have the space in front of the lower crankshaft pulley, consider installing a Johnson crankshaft pump.
Four little screws removed, one cover removed, and you're right there at the impeller.
No side load on the shaft bearings from belt tension, one belt and set of pulleys to rid yourself of, and easy impeller access, etc etc.



 
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sterlin318 said:
the front of the motor looks pretty full, is there any specific way you guys are mounting them?
Click to expand...
The V-belt pulley is removed from the crankshaft harmonic balancer, leaving only the GM crankshaft pulley.
The GM pulley allows the Johnson pump to mount to it via the three harmonic balancer threaded holes.
The Johnson pump indexes via two raised dowels in the crank pulley. IOW, out of three possible positions, only one fits.

The three bolts become longer, and there ya go.
 

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okay, gotcha now, your picture of the motor didn't show up before, I have plenty of room for that as i am building a new interior for the boat i can just slide the back seat up a little bit if it doesn't clear. thanks for the help, im going to make sure everything will work and order one tonight!
 
Do a search.

Once in a while you can find the F5B-9 for as low as $150 complete with new impeller.

The other beauty is..... this pump uses a very common #1027 impeller.



BTW, the F6B-9 is a larger volume pump.


.
 
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