Merc BP

**BobbyZ28** · 12-23-2020, 07:00 PM

I am looking at purchasing a 1969 Merc BP engine to go on a vintage Allison speedboat. I remember those motors from back in the day. I can't remember what makes them differentl and what BP stands for. I know they came out as 125BP but were there any 150BPs? Can someone help me out with this and what might be a fair price for one in running condition?
Thanks!

**peterse90** · 12-23-2020, 08:31 PM

No such thing as a 150BP.
1000BP - 89.9 ci
1250BP - 99.9ci
I think in 1969 the 1250BP became a 1250SBP (Super BP). Someone else will have to expand on what made the Super - Super.

**Tom Smyth** · 12-24-2020, 08:08 AM

The 1250 BP was a stock 125 hp power head mated to a BP midsection and ran a shiftable three pinion racing gear case. Rated at 125 hp at the fly wheel.

The 1250 SBP was the first direct charge inline 6 and basically the prototype of the 1350 production engine. Mounted on a BP midsection and running the same shiftable racing gear case.. HP estimates were around 140 ish although actual numbers were never published.

Most 1250 SBP power heads floating around 5hese days are not true SBP blocks since they only produced 249 of them in 1968/69. Most are fishing motor 1350 blocks since they are much more available, the original ones having bit the dust long ago.

price is VERY dependent on what you actually have. Pics would help identify that along with a serial number.

**FMP** · 12-24-2020, 10:09 AM

^^^
Shiftable

**WaterZebra** · 12-24-2020, 10:14 AM

Originally Posted by BobbyZ28

I am looking at purchasing a 1969 Merc BP engine to go on a vintage Allison speedboat. I remember those motors from back in the day. I can't remember what makes them differentl and what BP stands for. I know they came out as 125BP but were there any 150BPs? Can someone help me out with this and what might be a fair price for one in running condition?
Thanks!

A time era BP that still runs will be hard to find. Their gearcases are a nightmare to take care of. It may have been a "shiftable" gearcase but was a theory only. Propellers for a BP are nearly impossible to find. What would really be great sitting on that old Allison's transom would be a Merc 1500XS or even an 850XS. Far more reliable with parts and propellers easier to find.

I'd keep that old bronze 2 blade on the motor you removed from that boat. Merc 2 blade props of any pitch are getting hard to find thanks to the passage of time and metal thieves.

**Tom Smyth** · 12-24-2020, 11:03 AM

almost a BP. close though....

**OLEGATOR** · 12-24-2020, 12:35 PM

Originally Posted by Tom Smyth

The 1250 BP was a stock 125 hp power head mated to a BP midsection and ran a shiftable three pinion racing gear case. Rated at 125 hp at the fly wheel.

The 1250 SBP was the first direct charge inline 6 and basically the prototype of the 1350 production engine. Mounted on a BP midsection and running the same shiftable racing gear case.. HP estimates were around 140 ish although actual numbers were never published.

Most 1250 SBP power heads floating around 5hese days are not true SBP blocks since they only produced 249 of them in 1968/69. Most are fishing motor 1350 blocks since they are much more available, the original ones having bit the dust long ago.

price is VERY dependent on what you actually have. Pics would help identify that along with a serial number.

almost correct, but close though.

**Mark75H** · 12-24-2020, 06:56 PM

Originally Posted by BobbyZ28

I am looking at purchasing a 1969 Merc BP engine to go on a vintage Allison speedboat. I remember those motors from back in the day. I can't remember what makes them differentl and what BP stands for. I know they came out as 125BP but were there any 150BPs? Can someone help me out with this and what might be a fair price for one in running condition?
Thanks!

Original, complete and running probably north of $5k.

**Mark75H** · 12-24-2020, 06:59 PM

I didn't see that the "BP" question hasn't been answered yet

Blue Printed

**Dave S** · 12-25-2020, 01:44 PM

Burnt Piston

**Tom Smyth** · 12-25-2020, 02:52 PM

Blue Printed....... but not really.....

**Mark75H** · 12-26-2020, 09:46 AM

Originally Posted by Tom Smyth

Blue Printed....... but not really.....

But have you ever really checked a sealed block for weigh match and true crank? Could have been without any visual indication - and - it does make a difference.

**Tom Smyth** · 12-26-2020, 11:16 AM

Agreed. Never an unopened BP or SBP powerhead has crossed my workbench. But i know how far off typical fishing motors weights can be ....

**GENE LANHAM** · 01-01-2021, 01:47 AM

Originally Posted by Tom Smyth

almost a BP. close though....

By 1971--not a lot of SBP's running---But a lot of driveshaft housing-ADAPTERS-- and brand new 1350 power-heads with decals---choose your lower unit--

Click image for larger version.

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**starviper10** · 01-27-2021, 10:50 AM

Originally Posted by BobbyZ28

I am looking at purchasing a 1969 Merc BP engine to go on a vintage Allison speedboat. I remember those motors from back in the day. I can't remember what makes them differentl and what BP stands for. I know they came out as 125BP but were there any 150BPs? Can someone help me out with this and what might be a fair price for one in running condition?
Thanks!

Any pictures handy of the 1250BP you were looking at?