Can I put a 150 hp Force motor on a 125 hp Force mid-section and lower unit?

pastorbud

Chief Petty Officer
Joined
Jun 1, 2005
Messages
555
So I kinda got my eye on a 21 foot Wellcraft with a dead 150 Evinrude on it. My current boat is a 1987 Bayliner center console with a 1987 Force 125 hp. I could just swap the 125 Force over to the Wellcraft, but it would be a little underpowered, I think.

So... I found a sweet deal on a running, 1989, 150 hp Force 5-cylinder, but it has no lower unit. Is there a way to know if my existing lower unit and mid-section can be bolted onto this engine?

It sure LOOKS like my motor with one more cylinder! :rolleyes:
 
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Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Yep! You can do it. The reason for the large plate on the exhaust is this: Top two cylinders and bottom two cylinders have special exhaust "guides" While the center cylinder also has one but it is not siamesed with another cylinder. The net effect is a mild tuning and the engine runs like a scalded cat. It will make your 125 look sick. That massive cooling chamber on the exhaust side does not go down to the mounting bolts.

Concrete example: A 125 on my 21 foot cuddy topped out a 33. The 150 (big bore version) does about 40 with the bimini down and about 43 with the bimini up. I suspect the bimini acts like a wing and helps lift the hull out of the water.

If you for some reason remove the head be careful. The head gasket alone is 65 bucks.

These engines do tend to flip out the top rings so ask the seller for compression ratio on all cylinders. However at 150 bucks it is still a steal and pistons are relatively easy to replace so it still is worth your while.

I have some easily accessible photos of the exhaust system so if you can guide me to posting them I will do so.
 
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