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7.4L Mercruiser Cooling Issues

Well,
Maybe supply as much info as possible.

Pictures help.
Year of boat helps
Serial numbers help

What if I asked you,

I have a truck with a 454 ci engine.
What transmission do I have and what rear end?
 
1986 Bayliner 2655 Cierra SB. 7.4L Mercruiser. Bought the boat last spring. It has been neglected for sure. First time out it over heated so took it back to the slip and used another boat the rest of the season. Had it hauled out in the fall and just getting around to it. It looks like an Alpha 1 second generation. No impeller in the bottom half like the others I've had and no bottom drain plug to drain the gear lube. It has what looks like a "raw sea water" pump located down low on the right side of the motor. I am disassembling the front of the motor now to get to the lower pump. I will attach photos once I get back to the shop. Thanks in advance for any info.
Regards
DEM
 
Bravo drive were introduced in ~ 1989/1990.

That being said,

If the gear lube drain plug is behind the prop then its a Bravo.

Alpha gen 1 vs Gen 2 is very easy to tell apart.
Gen 1 has two nuts towards nose of drive in small pockets which are part of the upper to lower mounting system.

Gen 2 has 4 visable bolts with nuts Wich bolt the upper to the lower.

BOTH have impellers in drives BUT they may be omitted when using thru hull on engine water pump impellers.

Bravo drive do NOT have impellers ib the drive.

By any chance does the engine have a transmission on the back of the block where shifting occurrs?
If so you could have a TRS drive.
 
One more thing, It is possible the boat was repowered to a bravo set up.
It would only require the transom assembly and drive.

A boat that size and weight would destroy an alpha drive.
 
kghost said:
Bravo drive were introduced in ~ 1989/1990.

That being said,

If the gear lube drain plug is behind the prop then its a Bravo.

Alpha gen 1 vs Gen 2 is very easy to tell apart.
Gen 1 has two nuts towards nose of drive in small pockets which are part of the upper to lower mounting system.

Gen 2 has 4 visable bolts with nuts Wich bolt the upper to the lower.

BOTH have impellers in drives BUT they may be omitted when using thru hull on engine water pump impellers.

Bravo drive do NOT have impellers ib the drive.

By any chance does the engine have a transmission on the back of the block where shifting occurrs?
If so you could have a TRS drive.
Click to expand...
The bottom drive attaches to the top with 6 nuts 4 studs on the top portion and 2 studs on the bottom. I did not look for a drain plug behind the prop I will when I get back. There is not a shifter shaft between the two outdrive halves so this makes sense. Thus far I have not located any identification markings. Where would they be if this is in fact a Bravo drive instead of an Alpha?
Thanks for your assistance
DEM
 
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