Just got another motor put my boat and when I hammer down on it, its like its "spinning out" (rpms go up and it goes no where).  When I ease into it, it does fine.  Is there a problem with the motor or is it how I am taking off or what?????  Any help would be appreciated!!

Sounds like the prop is munched to me...causing too much cavitation. It's like spinning your tires in a car that doesn't have good grip. If you step on it the tires will spin but if you ease into it you're all good. Now I don't know how this effects traditional boats...but a PWC with a banged up prop will do what you are describing. If the prop is really banged up, the PWC wont move no matter how much you ease the throttle. It could also be that the prop is the wrong size and/or pitch for your setup.

what you have is called "blow-out", it can be caused by a couple of different issues.

it can be caused by having the motor set too high on the jackplate or if you have a prop with the PVS plugs in it, you can have too many out or the wrong sizes in.

need some more info on your exact setup.

kind and size of prop, motor size, height of prop center line in relation to pad on boat.

actually there is a third issue, you could be spinning the hub in the prop, if this it should show by running at mid throttle and goosing it. if it slipping you should see a sudden rise in the rpms.

You're really going to need to provide a lot more info to begin to troubleshoot this problem.

Pull off your prop and see if its got melted rubber around the hub. Sounds like your hub is spun.

Normally a spun hub will not hold to run WOT, even if you can ease out of the hole and get it on plane.

As mentioned, sounds like the prop is over venting or too high and sucking air down when you nail the gas.

Type prop, through the hub, over the hub, vented or non-vented, prop shaft height, setback, does it have the proper thrust washer etc.  These are all things that need to be looked at and checked.

Is it when boat is just sitting still and you nail the gas that it cavitates/slips or just as the boat starts to lay over to get on plane?    

This is my first boat so I am not quite sure as to several of the things mentioned like the position on the jack part, if its spun, etc...  What I can provide is it is a 150 Johnson Faststrike, and the "blow-out" occurs when the boat comes on plane.  It is fine when down (starting off from idle) in the water comming out, but when the front end starts comming down and it gets on plane is when it does it (like the water just leaves the motor and I have to slow it down before it catches again).  At mid throttle and WOT it is fine it seems to me, I have had no trouble in either area.  The prop is a 4 blade SS Renegade Bass with a 25 pitch.  The boat that its on is a Stratos 278 model.  I believe that I am going to call the mechanic that I bought the motor from and have him solve the problem.  

With out knowing the exact set-up, it sounds like the motor is sitting too high. Are you trimming the motor all the way down before taking off? Does the prop have the blowout/weed ring installed?

You may want to call Stratos, they will tell you what pitch prop and the height you should be running. You may have to go to a 3 blade. My boat when I switched to a 4 blade same pitch prop, it made my RPM's go up and I hade to keep my jackplate down. If you are close to a lake, you may be able to take several diff. props out and mess around with them untill you find the one that makes your boat do what you want it to.

That's where I figured you were having the problem, that's why I asked.

There can be a couple of causes of this problem and your's is not an uncommon problem. My Stratos 285 Pro did the same thing when I first put one of my hotrod looper motors on it. A good prop man can rework the prop and cure the problem, for about $350. You can pull your hair out messing with the setup, drop the motor another couple of inches, try a different prop and might get it fixed, but there is a very easy and inexpensive cure.

The cheapest and easiest fix is to go to BPS and get you a SE SPORT 300 hydrofoil and put it on the motor, cost about $40.

This should totally cure the problem and also give you a much better hole shot to boot. Been there, done that many times and I've never seen one the SE 300 didn't cure the problem. If you want to try and fix it without the SE 300, drop the motor about three inches and make sure your are trimmed all the way in coming on plane. If it doesn't have one will want to get a blowout ring for the gade also, this will probably cure the problem and then you can start raising the motor up in 1/4" increments.

Make sure you have the proper thrust washer, the gade takes a smaller one than most other props and I've seen more than one gade with the wrong one.  Pull the prop off and that big washer behind the prop off.  Make sure the shoulder on that big washer fits down inside the prop hub and the flange is resting on the hup.

I put one on that 285 several years ago to fix it until I could get the prop tuned. Loved it so much, after getting the prop reworked, it's still on that motor today, even though it's no longer needed to get on plane.

Do you trim the motor all the way down before hitting the throttle?  Since you mentioned this is your first boat, you may not know you need to trim it all the way down first, and then start trimming it back up after the front end starts to come down.  If you start with the motor trimmed up, the bow will come up high, and then as it comes down your RPMs will shoot up with little gain..... then you'll porpoise a little before it finally begins to smooth out as it gains speed.

A takes a little practice with the trim switch to learn when and how much trim to adjust as you're gaining speed.  So don't worry about "getting it right" at first -- just improving as you learn the "sweet spots".

Hope that helps!

P.S. Don't slam the throttle all the way down when you start.  You're hole shot will be faster if you do it a bit slower.  It's much like flooring it on your car - you'll go faster if you don't burn out.  Plus, slamming it down puts a lot of stress on the prop and will weaken it.  Eventually, you'll spin it on something seemingly simple, and wonder why.

Thanks guys for all the input and help....Ive takin it out on the lake everyday this weekend so far, and yes it is trimmed all the way down when taking off, and I dont begin to trim it up until it is on plane.  I found that when washes out, especially when there are more than 2 people in the boat, if the RPM's get over 3500 when taking off.  When there are just 2 in the boat it is not so bad, but will still do it some.  

Can anyone tell me where I can order a ventalation ring/blow out ring to put on my prop.  I talked to the mechanic that I bought the motor from and he said to try that since there isnt one on the prop.