I purchased a nitro 882 with 150 mercury.  this is my first high performace boat.  I am having a problem with planing.  when i trim down to take off and get on plane the boat porpoises and when i trim even further down to stop the porpose problem the motor alarm goes off.  i get on plane at about 3000 rpm.  if i do not trim down to get on plane the front of the boat comes way out of the water and will not get up on plane.  any suggestions.  thanx

Welcome aboard!

Welcome aboard!

;D

Welcome to the wonderful world of bass boating. I take it you didn't take this out for a test spin, letting an experienced, qualified boater drive it for you before purchasing?

You need to provide more data. This could be as easy as you not running it correctly to the prop being incorrect or the engine height off.

What type of prop are you running(pitch and number of blades, the brand would be helpful but not necessary)?

What is the engine height set at (measured with the engine in the down position with a straight edge running out from the very bottom of the boat perpendicular to the motor. Measure from the straight edge to the prop shaft center)?

Are you using a jackplate (Width of the jackplate from the transom to the outer plate, where is it set at)?

Are you using a hydrofoil, doelfin or any other type of boat performance enhancing device like these?

What is your maximum rpm at Wide Open Throttle?

Is this porpoising with the boat empty or loaded?

I'm assuming this is a used boat since BPS no longer sells the 882. You need to give us information as to what you're running to even begin tackling this.  Explain exactly how you're running this boat from a dead start to plane.

this was my fathers boat. sad to say he is no longer here to show me how to use it. i am sure he less than 100 hours on the motor. he got sick not long after he bought it.  it has original prop and engine height set at factory. no jackplate. it has a hydrofoil he put on when he bought it. never had it wide open. porpoising is with just me in boat.

the prop is 3 blade. from a dead start i get the rpms up to about 1800 slowly and then give it about 3/4 throttle to get it on plane. i start with it trimmed about 1/2 way between level and all under. i try to run at about 3500 rpm. when i get it on plane it starts to porpoise and i trim it furthur down to stop it then begin to trim it back up slowly. i bought boat from my mother after he passed. she said he never seemed to have a problem with it. I wondered if i was trimming it under too much and water is blocking the exhaust and causing the engine trouble warning to go off before i get it trimmed back up? i took the hydrofoil off to see if it ran better without it but it ran worse.

First, you are trying to come out of the hole with the motor trimed out way too far if you're getting that much bow lift.

You should be able to come out of the hole with the motor trimed in a little from neutral and should have a better hole shot with the motor trimed all the way in. If you are having problems coming out with the motor fully tucked, you have setup problems. THe alarm my be oil level problems or sensor problems but if you constantly get and alarm with the motor tucked, (trimmed all the way in) you need to have that checked out, it's not suppose to do that. Porposing is telling you the boat is trimmed too high.

If running a vented prop, the motor is suppose to rev up to about 3,500 rpm when it coming out of the hole. That's called controlled cavitation, it lets the motor spin up into the peak torque band to help get the motor on plane quicker. It will start out slowly gaining rpm and then make a quick jump to about 3,500 and the boat should quickly start gaining speed. When the boat speed catches up with the rpm, the cavitation goes away.

As cart7 mention, there are some other numbers that would help. Max rpm the boat will turn at WOT and properly timmed out. Prop pitch and type, motor height and other things also have a major part in how you come out of the hole

Just read your last post, you should be able to nail the gas to WOT and come out of the hole without letting off.  Hydrofoil tells me he was having problems also.

W2S is right on.  Right off the bat it sounds like you're not running the thing correctly to begin with.  You should be tucking that motor most of the way down from a deadstart.

Another thing you may want to try is giving a Nitro boat dealer a call and taking that boat in to them to see if the engine's set at the right height on the transom.  It almost sounds like it may have been set wrong from the git go if your Dad was running a doelfin on it.  A Nitro dealer should have a pretty good idea of the best engine height and prop pitch for that boat to perform best.  

I trim all the way under for hole shot. Punch it with full throttle until I get on plane then I back the throttle off a bit and trim out until I reach what I call the "sweet spot". You should recognize the "sweet spot" by engine noise and no prop torque at the helm. On my boat you can loosen your grip on the wheel and go straight down the lake. Then I increase the throttle to the desitred speed and still go straight down the lake.

All of this takes only seconds and your boat is very stable. I go straight down the lake with no steer torque when I have the boat set up properly. I do have a plate on mine called "The Edge" which is just a metal plate with the trailing edge turned down a bit. It seemed to give me a slightly better hole shot.

If you reduce the throttle you will hit a speed(throttle position) where the boat starts to porpoise. To stop the porpoising you either tuck the engine under a bit(I mean just a tap or two) or give it just a bit more throttle.

On occasion I get stupid and forget to trim under before I start out and you are right the bow comes way up and you don't get up on plane. It is dangerous since you can't see. When I get stupid I back the throttle off and trim under; then go again.

A huge number of bass boats go down the lake trimmed out way too far with a huge rooster tail. I have read and it applies to my boat that the rooster tail should not be higher than the engine cowl.

I should have mentioned that when I trim out I just tap the switch a few times to reach the "sweet spot"

I recently had a problem with my boat planing and couldn't figure out why.  I messed around with the engine tilt and that easily fixed it.  With mine, I gun it with the tilt about 75 degrees and as I'm taking off, I dig the motor all the way in and it planes out very quickly.