Hello I am a first time boat owner long time fisherman so my boat is a late 70s early 80s steury fiberglass fishing boat I am in the process of refurbishing it so I just picked up a 20 horse chrysler outboard which is also early 80s when hung on the boat the cavitation plate is to low how can I raise the engine? It doesn't have any type of height adjustment.   Thanks

I could be wrong but I'm not sure that's too low to worry about. In terms of cavitation, I'd think it's better too low than too high (prop grabbing air). Thinking you might be allright as-is, at least get it on the water and see how it performs before making any adjustments. Congrats on the new boat!

 

 

Better to be below pad than above pad

Could be a problem backing down the ramp. Those 4 small holes usually have a metal rod where you can select the setting you want by lifting the motor and inserting rod into a certain hole. It could be missing or broken or both. Trailering and loading/unloading would concern me more than operation.

Just raise it to the height you want and drill the four mounting holes though the transom.  Those hooks that go over the transom do not have to be resting on the transom.  If you currently have holes from a previous motor, be sure fill/plug them very well so no water can seep by them.

 

The four holes mentioned in a previous post are for setting the tilt angle.  If you don't have the pin that goes in them, you need to make one.  Tilted all the way in like that would not make for a very good setup.

 

However, looking at the boat, you have a long way to go before you have to worry about any of it. 

The first thing I would do is stick a couple of large bolts with large washers on both sides though the existing holes  and torque them down. If they pull the washers and fiberglass under them down into the transom, anything you do is going to be wasted effort because the transom is rotted and not safe to mount a motor on. 

You have a 25" long shaft engine that is 5" longer then the 20" standard shaft engines the boat is designed for. 

It appears Chrysler added a 5" lower unit extension and you might want to look into removing it if a 20" shaft will work?

I don't believe it's possible to raise the engine 5" and still have 4 bolt pattern for the transom?

Tom

PS, get a hammer and knock on your trailer frame it maybe rusted through!