Hard steer

[David Scogin]

I have a 2011 Z7 150 ProXS. Mercury recommends 5250 to 5750 rpm. I can only get around 5200 RPMs.(about 57-58MPH)Have to trim motor at highest trim for fastest speed and most RPMs. Dealer said they set up the boat with one person and 12 gals of fuel. I run with mostly full of fuel and 2 people and would like to see higher RPMs. I have a 24p Tempest prop, I tried a 23p and gained 200 more RPMs but lost 5-6 MPH.(about 52-53MPH) so that didn't work. Also cannot hardly turn left without both arms and all muscle after boat is on plane, its really frustrating. Does anyone think the addition of a 6 inch Jackplate would help to resolve these issues? Any other suggestions? Thanks.

 

[Jim B]

It sounds to me like they set your motor too low. Im sure Bob B will be along and he can offer you some advice on where it should be without a plate and just about anything else concerning the setup. He is the man when it comes to this stuff.



Personally i think a jackplate will help a lot. My Z7 with a 175 Pro XS can turn 6k easy with a 24 tempest, i also have the motor jacked 2.5" below pad.



I helped a member here set up his Z7 with a 150 when he had it and with a 6" plate with the propshaft at 2 3/4" below pad and a 23 tempest it ran a solid 62 at 5600 rpm and the hoelshot was great and the water pressure was good. The 23 tempest seemed like the right prop for that boat/motor combo.



I also disagree with your dealer on the fuel and person load. Personally i like to set my boat up with like half a tank or more of fuel and an extra guy. that way when i get it decent under those conditions it really runs awesome when im alone and the boat is light.

 

[Bob Bourget2]

The motor should be mounted in the second hole, or 3/4 inch above transom*. How much time do you have on the engine? I would also assume that you have conventional cable steering, not hydraulic?

*Hydraulic equipped boats can be mounted 1.5" AT....

 

[David Scogin]

Sorry I didn't clarify, it has does have hydraulic steering, that is one reason it bothers me, I don't think it should take both hands just to turn left. As far as the below pad number, I measured but don't remember, I will try to check again at lunch today. Motor has right at 23-24 hrs. And I am 99% it is mounted in second hole, but check that again at lunch today. Thanks again.

 

[Bob Bourget2]

Just out of curiosity, the 23" Tempest you tried....was it a new prop or rebuilt? Something VERY wrong with those numbers....

 

[David Scogin]

It was a used prop but in excellent shape, it came off a friend of mines Ranger boat, he runs more RPMs than he wants to so we swapped to try and see what would happen. Yeah kinda freaked me out too, but speed numbers were GPS and RPMs went to 5400 from 5200. It made a big difference in the hole shot but killed top end.:wacko:

 

[Bob Bourget2]

But was it rebuilt? It sounds as though it was not rebuilt properly. HOWEVER...we are skirting the issue....

-1] The motor can be raised to 1.5" AT. Per spec.

-2] Steering. Again, the assumption is that the steering torque is at WOT, at full trim. I don't know of many boats that would be different. This is where a jack plate will help. Set-back will enable you to achieve the same speed with less trim, and less steering torque. You MIGHT even gain a little speed.

-3] Give the motor more time to break-in. They usually need close to 50 hours before they loosen up. With the coming of cooler, drier air, you will also see a speed increase.

-4] The prop on your boat is the correct prop for that application. Give it time....

 

[David Scogin]

I was wrong Motor is in middle hole, 1 inch above transom,(If I measured at right place.) Prop is 3-3/4 inch below pad. Motor is very hard to left anytime while on plane, trim doesn't affect it alot but it is worse and almost not manageable at full trim. Also Highest RPM at full trim and fastest speed, It kinda feels like it would do better if it could trim higher but already throws water at engine height if not over that height. (Kinda hard to tell when driving.) I can sorta deal with the RPMs and speed and can wait if jackplate is needed to correct, but the steering is a safety concern for me. A 5 mile run will wear you out.

 

[Bob Bourget2]

Measurement is from transom top to the "flat" of the motor bracket where it would "sit" on top of the transom if lowered. Your description of rooster tail and trim requirements lead me to believe there might be a weight distribution issue. Do you have much gear {or anything} forward of the consoles?

 

[David Scogin]

Not a weight distribution issue. 7-8 rods on left side, misc on right side but not much weight at all, Tackle in middle box up front. I have tried moving stuff around but no difference at all. I have taken everything out except rods and tackle, with no difference. I guess I'll take to dealer and have them check it out, spoke to them earlier and he said boat should turn either way easily. The steering at full trim and WOT is so hard to left, I basically have to use both hands at upper left of wheel, pull down and reach up and pull down again just to turn. I believe something just ain't right the way it is setup. As I type this I recall my last boat had manual steering and it was much easier to turn. At idle and low speed It will turn fine, speed up and trim it and it don't wanna go left. It makes me believe it has something to do with the torque of prop.

 

[Bob Bourget2]

If the motor is at full trim, no matter what kind of steering, on a right hand rotation equipped motor, it will have tremendous steering torque, to the left....especially going 50+ mph. If it steers normally, {and you should be able to find a neutral, either direction} with trim adjustment, chances are there is no issue.

 

[David Scogin]

Thanks for the responses.

 

[Bob Bourget2]

No problem Dave. Glad we can help.