Mercury/Mariner Blocks Interchangeable?

[NitroTime]

Hello All, I hope everyone's doing great!

I'm quite new to the community/forum, I apologize in advance if this has been previously covered, or addressed. It's only since some preliminary searching came up empty that I'm asking.

As a result of COVID-19, and the restrictions towards the beginning, it killed business on a massive scale in my industry, and at the end of March, I was laid off from my job. 6 months later, I'm still unemployed, so money's tight to say the least...

I've just recently bought a used boat for $1500, it's a 2000 ProCraft 190 Super Pro, with a 2000 Mercury 150 Optimax. The previous owner said that "out of the blue", the lower unit croaked, the driveshaft to crankshaft splines stripped, or spun, and the end of the driveshaft does look some kind of bad!

But the motor starts up right away, sounds great, just no lower unit now.

A friend of mine has a 1999 Mariner 150 Magnum III that crapped out, the dealer said the block, and 1 cylinder is bad, everything else is in good shape. My question is, can I put my 2000 Mercury 150 Optimax block in a 1999 Mariner 150 Magnum III?

The shorter way of asking, is the 2000 Mercury 150 Optimax, and 1999 Mariner 150 Magnum III blocks interchangeable? (quietly praying, "please say yes, please say yes, please say yes")

Sorry for the long winded post, just want to try and word it correctly.

I've grown up turning wrenches, the mechanical aspect I'm comfortable with, just not sure if the blocks are interchangeable, and I'm praying, praying, and then praying some more that they are interchangeable.

Any help, advice, and/answers are GREATLY appreciated!

Thank you,
-Nitro

 

[Chris1956]

The gearcases are very likely the same, provided both motors have the same shaft length. Isn't that what you want?

It is a lot easier to swap gearcases than blocks. Put a new waterpump in the new gearcase, before you install it.

You need to check the spines on the end of the crankshaft. If they are stripped, it will ruin the splines on the 1999 gearcase.

Crankshafts between the two motors may also be the same, but you will need to verify.

 

[NitroTime]

The gearcases are very likely the same, provided both motors have the same shaft length. Isn't that what you want?

It is a lot easier to swap gearcases than blocks. Put a new waterpump in the new gearcase, before you install it.

You need to check the spines on the end of the crankshaft. If they are stripped, it will ruin the splines on the 1999 gearcase.

Crankshafts between the two motors may also be the same, but you will need to verify.

Thank you for the reply...
The 1999 Mariner is a complete outboard, everything's in great shape, including the crankshaft, except the block itself, and 1 piston.
I was hoping I could take my 2000 Mercury block, with pistons, put the Mariner crankshaft in my Mercury block, and then put it in the Mariner. It'll be Mariner everything, except the block, and pistons.

Here's the Mariner I'm hoping my block will bolt in. That way all shafts, and splines will be the same as it was on day one.

And a picture of the stripped driveshaft from the Mercury.

 

[Chris1956]

Thank you for the reply...
The 1999 Mariner is a complete outboard, everything's in great shape, including the crankshaft, except the block itself, and 1 piston.
I was hoping I could take my 2000 Mercury block, with pistons, put the Mariner crankshaft in my Mercury block, and then put it in the Mariner. It'll be Mariner everything, except the block, and pistons.

Here's the Mariner I'm hoping my block will bolt in. That way all shafts, and splines will be the same as it was on day one.

And a picture of the stripped driveshaft from the Mercury.

You realize that Mariner and Mercury are made by the same company, right? The difference between same year and type 150HP Merc and 150HP Mariner, is the color of the paint and the decals on the motor.

However, the Optimax is a different type of motor than the EFI Mariner. Optimax is a Direct Injected outboard. Only air is drawn into the crankcase, and oil is injected into the crankcase. Gasoline is injected into the combustion chambers after the ports are closed, and then burned.

EFI has a throttle body instead of carbs, but that is the only real difference between it and a carb motor. A mixture of gasoline and oil is drawn into the crankcase, from the throttle body, and transferred to the combustion chamber and burned.

They might share crankshafts, but you will need to get on the crowleymarine site or some parts other and see if you can match part numbers for the crankshafts. I expect the gearcases and midsections will be the same. The cowling may be different, due to the compressor and other Direct Injection-only parts on the Optimax.

 

[Dukedog]

ya need ta check out tha crank shaft splines... that looks bad enough ta mess those up to... might need ta change out crank.. wouldn't worry with anything else.. all 2.0/2.4/2.5 (carb, efi, opti) gearcases will interchange.. only difference will be in gear ratio's......

 

[Faztbullet]

According to crank part number cranks are different,no oiling gear feature and uses bottom guided vs 150EFi which is top guided pistons.

 

[QBhoy]

Different engine from the optimax as far as I know. I think the mariner magnum is an efi 2.0l thing is it not ? Optimax being a direct injection newer type ? Might be wrong. The mariners have different life span cycles over there from here.