Boat with no lift

[Kirby Wilson]

Just bought a 2011 Z7 with a 150 optimax. Have had it out twice and both time it has very little lift at full trim. 24 pitch tempest plus prop turning 5400 rpm. 47 to 48 mph gps. Motor is in the 3rd hole.

Have around 75 lbs tackle in the center front storage, full take of gas and 425 person weight. Any sugestions?

 

[Sean Troy]

Is the 5400 RPM at WOT? Seems a little on the low side.

 

[Kevin Broussard]

Humm, something's not adding up. I have the same boat but a pro XS, same load, same RPM, same prop and I run 50-52 MPH. WOT I can spin it 5700.

 

[Sean Troy]

Sounds like it may not actually be trimmed correctly?

 

[Kirby Wilson]

The boat lifts a little untill about half of the trim travel. What about a jack plate?

 

[Kirby Wilson]

With out trim 5000 rpm

 

[tony silveira]

Your not going by trim gauge are you? I know mine isn't accurate at all. I just go by feel.

 

[Kirby Wilson]

I can feel the boat lift a little untill about half way on the trim gauge and the hight of the rooster tail. Can see water spray about 2 feet in front of me.

 

[THOMMO59]

Your trim gauge is easily adjusted. When your engine is trimmed right in, the gauge should just hit the bottom mark. If it doesn't, tilt your engine up, back off the 2 x 5/16' screws that tighten the sender ans move it a little a time and retest and you will get it perfect in no time. Also, check that you engines power trim isn't actually creeping down under load.

Trim the engine to max trim, take exact notice of the position or take a buddy to watch. Try to get on the plane and if the trim is leaking down , the motor will move by itself.

This would account for not getting the lift you want and also low revs as the boat basically plows through the water.

 

[Kirby Wilson]

Thanks for the info

The trim is working correctly

 

[Scott Hammer TOXIC]

You do know that after you reach and pass the "sweet spot" trimming, your performance will decrease? I say that because you mention "full trim". There is no such thing....your proper trim setting is somewhere in-between full tucked under (for holeshot) and fully trimmed out which is where your trim stops. Your boat will tell you where that is.

 

[Kirby Wilson]

There is no sweet spot The boat has very little lift and once the tirm is about half way up it has no more lift. I can see water spray about 2-3 ft. infront of the drivers seat.

 

[Scott Hammer TOXIC]

If you are plowing water, you are not on plane. Give the details on how you take off in your boat. There is something wrong.

 

[Kirby Wilson]

Had the boat out this weekend. Full throttle the boat come on plane. Then when the boat is trimmed up it gains speed until it reaches 47mph GPS. The boat is at full trim and I can see water about even with the front of the console. The boat is lifting a little. The rooster tail is about 1 to 2ft above the motor. The motor is set in the 3rd hole from the top. RPM is 5350 calculating to about 28% prop slippage. Still cannot tell the boat is lifting after about 1/2 trim but it must be lifting a little to be gaining about 2mph with the last half of the trim. This is with 2 people, fishing tackle and full tank of gas. With one person 51.4mph @ 5500RPM

 

[Kirby Wilson]

Could a hook in the hull be causing the problem or would a jack plate help the problem?

Looking at the prop it looks ok, but may need to have it checked also. Before this boat I have a 350 ranger with a Mag II.

 

[Scott Hammer TOXIC]

If your rooster tail is 2 feet above the cowling of your motor you are over trimmed.



It should go no higher than the cowling

 

[Kirby Wilson]

I agree but the boat gains a little speed during the last part of the trim! Something not right.

 

[THOMMO59]

Something is very strange there Kirby, to give you a comparison, I have a 2011 Z6 with a 115hp and 22p laser prop. I can get 52mph on the GPS, absoultely flat knacker but I can tell you, the last 25% of my top end is all in the trim. Unless I keep trimming up until almost blow out, I just won't gain speed, regardless of what my trim guage tells me.

You almost sound like something is dragging you back down onto the water.

I'm really interested to see what the final outcome is, have you asked your local dealer to meet you at the laked to test?

 

[Kirby Wilson]

 

[Kirby Wilson]

Talk to the dealer and they are going to check it out.

Thanks for the info.

 

[Kirby Wilson]

Took the boat to the dealer today. Had a bad prop. Replaced the prop. The boat now has lift and pick-up speed. It was raining hard at Truman lake but pick-up about 5 to 6 mph.

 

[THOMMO59]

Excellent, glad you got it sorted.