I bought this boat a few months ago, its a 86 Cajun 18,6 ft with a Johnson 150. The only problem it really has it is very slow to get on plane does anyone have any ideas what it could be? Thanks

Most common cause is wrong prop pitch but it can be several things: weight distribution, motor problems or driver error.

I would agree the number one issue could be your prop, either wrong prop or damaged. You might also consider your motor height along with the suggestions Gary gave you.

How slow? Does it take a few mins to get on plane? Do you have to idle for a min or so 'till it "builds" up enough power to get plane?

Okay thanks that's what me and one of my friends talked about just was scared to go out and buy another prop and that not be the problem . That's got to be it because it runs to good after it gets on plane.

I would be concerned that the boat used to get on plane ok with that prop and now it doesn't. I would check for water soaked foam in the hull and loss of compression in the engine on that age of equipment. I would also post what pitch prop your running and having a problem with so we can get an idea if it ever would have worked properly.

I have had compression checked and it was fine. Now this is my first boat so I am not sure how I would check for soaked foam

It has 14.5 by 22 prop on it

How long does it take to get on plane? Mine has been doing something similar, but it takes about almost a min of idleing to get on plane. Figured out I had to push the choke button on the key a few times to get her up quick and found the bowls on my carbs were warped. Changing those out tomorrow when the new carbs get in. Could be a leak in your fuel system if this is your problem as well.

are you trimming the motor ALL the way down..??

I guess its possible I want to rebuild them before next spring anyways just need some extra time

Kingdad yes.

first, what are your wide open throttle (wot) rpm's?
what is the name of the prop ie. raker, tempest etc.
I assume its a 3 blade from the 14.5 dia., do the blades have any signs of damage, bends, big nicks etc?
get the compression checked on the engine or buy a compression test kit from one of the auto supplys, they are cheap and will come in handy.
you have a boat that is probably rated for a 175 or 200hp engine so the 150 is going to be underpowering it somewhat, how does it run when on plane?

one more thing, go get 2 cans of seafoam and add to whatever gas oil you have now, go run the peediddle out of it for about 30 mins. non stop.
park it and let it sit overnight then go run it again till the gas is almost gone.
this will pretty much decarb the engine and should help the performance quite a bit.
use the pennzoil full synthetic oil after that and you will be surprised how much better it runs.
may need some new plugs after the decarb but still its worth 40-50 $ for what it will do for the performance.

Not sure the brand of prop it is in storage,but it is a three blade and it does have one blade that has a little Nick,and when it is on plane runs great the tac doesn't work so I don't know the rpms on gps it runs at 48 mph