1980 Avenger weight and hp rating

spuddly

Recruit
Joined
May 26, 2025
Messages
2
Going to buy a 1980 avenger tomorrow for 3500. It's a 20ft 4 seater outboard with a Johnson gt150 on it.

I couldn't find the rating tag on it (though I didn't look too hard.) My brother did some googling on it and found posts saying they are only rated for 90hp. Though this one does have a heck of beefed up aluminum transom plate on it.

Just a bit concerned about it with if 3 other buddies in it too, to be honest. Seems like a solid boat and motor, will be my first boat with anything bigger than a 20hp tiller.

IMG_20250529_231741.jpgScreenshot_2025-05-29-23-17-14-26_a23b203fd3aafc6dcb84e438dda678b6.jpgScreenshot_2025-05-29-23-17-09-46_a23b203fd3aafc6dcb84e438dda678b6.jpgScreenshot_2025-05-29-23-17-04-87_a23b203fd3aafc6dcb84e438dda678b6.jpg
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,531
first, welcome aboard.

second, the band-aid plate on the transom is because the transom is most likely rotten. also check the floor and the hull core. these boats were known to rot.

Third. read this https://forums.iboats.com/threads/f...help-buying-a-boat-a-buyers-checklist.612841/

4th, read this. https://forums.iboats.com/threads/1995-sea-ray-220-signature-deck-and-stringer-restoration.495449/

the 183 Cee Bee avenger was rated at 150hp. Specifications ; Boat Type. Outboard Boats ; Hull Material. Fiberglass ; Beam. 7'5" ; Length. 20' ; Net Weight Lbs. 1100

Cee Bee boats was originally founded by Bob Brown (writer for powerboats magazine) cool boat, however the boat building technology was balsa core and wood. so inspect the boat inside/out. take it for a ride. with the motor trimmed up, have either a 400# friend jump on the prop, or have two 200# friends jump on the prop. there should be no movement of the transom where the motor clamp is. if there is, the boat needs hull restoration which will run you about $3500-$4000

there is a Cee Bee Boat Fans group on facetube
 

spuddly

Recruit
Joined
May 26, 2025
Messages
2
first, welcome aboard.

second, the band-aid plate on the transom is because the transom is most likely rotten. also check the floor and the hull core. these boats were known to rot.

Third. read this https://forums.iboats.com/threads/f...help-buying-a-boat-a-buyers-checklist.612841/

4th, read this. https://forums.iboats.com/threads/1995-sea-ray-220-signature-deck-and-stringer-restoration.495449/

the 183 Cee Bee avenger was rated at 150hp. Specifications ; Boat Type. Outboard Boats ; Hull Material. Fiberglass ; Beam. 7'5" ; Length. 20' ; Net Weight Lbs. 1100

Cee Bee boats was originally founded by Bob Brown (writer for powerboats magazine) cool boat, however the boat building technology was balsa core and wood. so inspect the boat inside/out. take it for a ride. with the motor trimmed up, have either a 400# friend jump on the prop, or have two 200# friends jump on the prop. there should be no movement of the transom where the motor clamp is. if there is, the boat needs hull restoration which will run you about $3500-$4000

there is a Cee Bee Boat Fans group on facetube
Thanks for the great write up! I looked it over pretty good yesterday, it's not in perfect condition but felt solid all around. I will definitely recheck everything through again. I know the gauges don't work, clear coat is coming off in places and some stress cracks on the front top (I would guess from people walking on it?) Motor didn't start up right away, but ran great once it did (old 2 stroke being finicky?)

That is a very good point about the transom. I don't have the option to test in water before I buy, nor a buddy to come with this time. I know it will move a good bit while on trailer, hope I can tell while on it.

It really shouldn't have any flex at all in transom??

The floor did have some flex, not really squish, from me walking on it I'm 230 though. I didn't see any kind of way to look underneath it into bilge. I'll look more into that.

It was bought by a retired couple in Arizona where they stay for the winter. Now it's up here in Michigan.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,531
I know it will move a good bit while on trailer, hope I can tell while on it.

It really shouldn't have any flex at all in transom??

The floor did have some flex, not really squish, from me walking on it I'm 230 though. I didn't see any kind of way to look underneath it into bilge. I'll look more into that.
a good transom will not move on the trailer. the whole boat may move with respect to the trailer, however the transom should not move with respect to the boat

a properly foamed floor will not flex with 500# walking on it.

there should be no visible movement or flex at all on the transom, and with 400# on the lower unit with the motor tilted all the way up, there should be no movement at all between the motor and the transom clamp. that motor during the hole shot is pushing a lot more than 400#

look for stress cracks in the transom fiberglass and rusty streaks around bolt holes and the transom plug tube. this is the tannic acid coming out of the wood (same thing that give cola and coffee its brown color) that means the wood has rotted. however the band-aid plate was the first indication that something may be amiss

remember, unlike an I/O where the load path of the prop to the mounts is almost in-line pushing the boat, an outboard is trying to pry the transom off the boat as its pushing the boat. the force of the prop is pushing in the middle of the transom, while simultaneously pulling the top of the transom backwards. that is why if the transom fails, the boat usually races the outboard to the bottom

the aluminum racing seats were not factory. its a common swap for when someone does floor work.

it may have had a transom and floor replacement.

get up under the back of the cap with a very bright flashlight. use a mirror on a stick or even your phone to look in areas you can not fit your head.
 

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,487
NEVER buy a boat without an in water test run !! Most who do...regret it later ! Your looking at a 45 year old glass boat that was designed and built to last 20 years tops. You have a 90% plus chance that it has a rotten wood skeleton. Looking and feel will not test for rotten wood. Due to age, you will end up more than doubling the price to get it water ready and probably much mire even if you did the structure work yourself ! For 3500, you could find a nice aluminum hull boat that only needs minor work to be water ready. If you choose to go thru with this project, be sure you have life jackets for passengers as they will probably need them. Good Luck !!
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,163
Gee, I have owned a '74 16' Avenger since 1980. It is rated for 85HP, but I ran a Merc 1500 for decades and now I run a Merc 135HPV6. It has a 3/8" thick aluminum plate covering most of the transom.

That dinky aluminum plate on the transom in the photo, is clearly not holding the transom together. It looks like a protective pad for the transom fiberglass under the transom clamp. Look for cracks on the transom top corners. That is where they usually start.

When I replaced the deck on my boat, about 15 years ago, I noticed the stringers were wrapped in FG. They had no rot at that time. I replaced the transom last year, as small cracks were occurring. Actually, the plywood transom was in pretty good shape, when I tore it out.

On my Avenger, takeoff speed is in the low 50's. You hit a wave at that speed, and she launches. Top speed is in the mid 60's, although I have never tried to maximize it.
 
Top