OMC Cobra 2.3 outdrive on 4.3 engine

[Lowkey727]

Hi guys, I have probably a stupid question. I recently purchased a 1990 19' Sunbird with a blown OMC Cobra 4.3 engine. I was hoping to just rebuild or replace the engine fairly fast and cheap, but having done some research I found that the tag on my outdrive says it's meant for a 2.3 liter engine? I know the gearing varies in outdrives based on what size engine they are being spun by, and since my engine threw a rod, I'm wondering if this is the cause? Or is there any chance the gearing inside this outdrive has been modified to accommodate the 4.3 engine, and if so how can I check? Really hoping to not have to replace both engine and outdrive! Any help and input would be GREATLY appreciated!!

 

[alldodge]

Howdy

Your issue will be moving motor mounts to accommodate the 4.3 motor. The drive will be lower geared so if you can find an increased prop pitch to handle the increase power the your good

 

[Lowkey727]

Howdy

Your issue will be moving motor mounts to accommodate the 4.3 motor. The drive will be lower geared so if you can find an increased prop pitch to handle the increase power the your good

Thanks AllDodge, but the boat came from the factory with the 4.3. There's a heavy bead of silicon around the outdrive housing so I'm guessing someone replaced the outdrive with the 2.3L outdrive that's currently on it. So if the prop is pitched right the gearing in the outdrive won't affect the new 4.3 by causing it to over rev, etc?

 

[alldodge]

the boat came from the factory with the 4.3

Always good to know all the info. You may be able to increase the prop pitch for the 4.3 if the drive has a lower ratio. Put it in gear and rotate it then count the turns going in and out