"HELP" Is this prop correct???

I have a Johnson 70 hp 1984 attached to a plylite fisherman 15 foot glass hull.
The problem is basically it doesn't like to get on the plane .
When I push the hammer down from standstill,the bow will rise ,and then it will slowly start moving ,On a clam day ,with 3 on board it can take up to a minute for it to get going on the plane
The motor has been pretty much rebuilt ,so there shouldn't be any problems there (I hope) It runs sweet.
I took some readings yesterday ,and noted that full noise I was doing about 20knots at 4700-4800 RPM
The prop is a 14x17 .Also as you will see there is very very little clearance between the tip of the prob and the plate .Is this ok ??
Also is the motor height ok??
Ohh yes and of course not to mention ,it drinks ALOT of gas
Please any help will be a god send ,as I(like most of you)have invested that much time and money into this project ,and getting frustrated with this last little problem .
HUGE Thanks in advance

Re: "HELP" Is this prop correct???

It drinks lots of gas because the engine is being lugged (like trying to climb a setep hill in your stick shift car in overdrive). That motor should be reving at 5500 rpm at wide open throttle so your numbers show that the prop has too much pitch. You don't mention what the pitch is on your current prop so we can't tell you how much to drop. RPM increases 200 rpm for each inch of pitch decrease. RPM decreases 200 for each inch of pitch increase. Numbers on your prop will be either a manufacturers part number or something like 13-3/4 x 19 (13-3/4 inches in diameter and 19 inches of pitch). Those numbers are either stamped on the barrel of the prop between the blades or they are on the hub where the nut is. You may need to remove the nut and washer to see them.

Re: "HELP" Is this prop correct???

I think your prop is about right. Prop clearance shouldn't be a problem.
Your lacking about 1200 rpm you can't make that up with a prop.
I think you have a motor issue.If its a 3 cylinder the first thing I would look at is
maybe one cylinder is dead.
Be sure the throttle is opening all the way.

Re: "HELP" Is this prop correct???

I had a look at the prop ,the only numbers on it are the ones I mentioned in my first post ,there is a photo there as well.

I will double check that all cylinders are running later ,however pretty sure they are ..Well I hope so !!!!
Thanks again

Re: "HELP" Is this prop correct???

Another possibility if the boat was stored improperly and allowed to sit out with water and snow standing in it the hullcould be deformed or the foam under the floor may have absorbed water usually right near the stern adding a couple of hundred pounds.

Re: "HELP" Is this prop correct???

Curiosity got the better of me ,and I drilled a 4" hole in the floor to find the foam was quite wet . These hulls never had buoyancy foam in them from new ,so at some stage this has been put in. There is now way the water can drain out .I just cut about quarter of the floor out and did find a bit of water in there after removing some of the foam .I will attempt to remove the rest over the next few days .I noticed that there is a lot more water near the stern of the boat . I hope this should help me out !!!
Huge thanks for the replies ..Keep you informed.

Re: "HELP" Is this prop correct???

Does the foam seem saturated?
Be sure you replace the foam. I believe they call it closed cell foam
to resist water intrusion.
You might look at the bottom to see if the shape seems uniform.A straight edge along the keel
will help tell.

Re: "HELP" Is this prop correct???

The foam has has been pumped into the floor ,as with the removed piece of floor you can see the holes that they made .the foam follows the contours of the hull .So now there is no drainage to the bung!
I have found that the foam gets wetter to the rear of the boat ,So it is a tiresome and painful task to remove it ,but I hope to have it all out in the next few days.
Thanks again...Keep you informed

Re: "HELP" Is this prop correct???

Thats too bad; but I think it will at least help your hole shot.
It would have to be awful heavy to only go 23. Good luck, lets hope for some real improvement.