200 opti,/20ft astro setup

[1pabassman]

I'm trying to set the height on my 1998 20ft astro bass boat,an a 200hp optimax,what is confusing me is where should the cavitation plate be level with ,thievery bottom of the boat or the step up on the transom which is 7 inches higher then the true bottom of the boat?, I have it level with the step up now but I'm worried about the water pickup,but the motor does have the low water pick up on the cone,?

[pmgoffjr]

"Pad" is the very bottom of the hull. You have a offset transom.
So, you're probably way too high, measure from the very most bottom of the hull, that's your starting point.

[1pabassman]

I dont understand, what do you mean measure from the bottom?,also if I go that low I would have to move the motor down 10 inches?

[Rip Bass]

The measuring point is the very bottom of the V on the hull. When people say to level the motor with the pad,it doesn’t mean to put them level,( at the same height), it means make the motor and pad parallel to each other. Once they are parallel,measure the vertical distance between them.To do this,I put a long enough straight edge under the pad,extend it to the nose of the lower unit,(center of the prop shaft), the hold the straight edge up to the pad with a bottle jack. Once the straight edge is in place and the motor is level,you measure the distance between the top of the straight edge and the center of the prop shaft. You’ll want to start with the shaft 3.5” under the pad. You may need to go up or down from there to get the best performance.
It sounds like you are several inches too high now and will not be able to plane out.

[1pabassman]

Awesome,I understand that,but,as the motor sits now I will have to go down about 6 inches but my skeg is already 1/4 inch from hitting the floor already? An it is a 20inch motor?,this dam astro trailer sits very low in the ack

[Tom Rollins]

To avoid dragging the skeg on the floor, simply trim the motor up.

[Rip Bass]

If you lower the tongue jack it will raise the back of the trailer. If that’s not enough you can pull the trailer tires up on some boards enough to trim the engine level. Using the method I mentioned above,the trailer doesn’t need to be level to the ground,only that the pad and engine are parallel.

[1pabassman]

Thanks for all the help guys,I mis worded the reply i didnt have to drop the motor down what i had to do was raise it 5 inches,and i got it set at 3inch below the hull,gonna try tommorrow with a 25 pitch and see where I'm at,theproblem was,i was running a 23p, and at wot i only got 50 mph at 5200 rpm,put a 21 pitch an wot was 51 at 5300 rpm so mercury said i could go either 24 or 25,so i had a 25 laying around so well se,oh fyi all the 2 props I tried had great holeshots ,last summer I ran a 175hp efi and run 63 full load, so this 200 pro xs got to be alot better than 50

[pmgoffjr]

Time out...
Is this a new motor?
If it is, it's ten hours before the computer lets it get out of break in mode.

[1pabassman]

No this motor is a 2011 an had 85 hr on it when I purchased in november,here is the disgusting results from yesturday test,I set the height to 3 in below pad,put a 25 pitch,it only run 47 mph an rpm were 4100 wot,swapped it out an put a 24 pitch fury 3 blade,ran 50 mph at 4700,went back to a 23 lazer,ran 51mph at 5000 rpm wot,at this point I am very concerned something is wrong with this motor that it is not running to it's full potential, I could really use some help figuring this out . Will the wrong battery In the boat affect the performance of the motor,since this is my first opti i didnt know i could not use a dual purpose battery even though i dont have problems starting except the first time starting it is a little sluggish but after that it cranks fine.

[pmgoffjr]

Take it to a qualified tech and get it diagnosed. You're running on less than six, and that motor will grenade quick if a cylinder isn't getting fuel.

[1pabassman]

That's what I was afraid of,thanks for the help, is there a way I could check so I dont have to pay that big bill,living on 800 a month disability dont go far. Also wouldnt that show up on my vessel view

[pmgoffjr]

A compression test will be your first task. If that’s good then at least you’ll know if you’re dealing with a dead duck or not.

[1pabassman]

Ok I did it yesterday and I got 125 on all 6cyl on a warm test, plus I have vessel view and when I was idling it every thing was perfect on the vessel view,no issues

[pmgoffjr]

There's way more things that can go haywire on a optimax than I can do much besides change plugs and impeller. You have something going on, but not sure where to direct you.

[1pabassman]

Yeah I'm convinced because I should be running mid 60's easy ,I'm calling to make an appt tommorrow

[1pabassman]

This is what sucks about buying a motor from a dealer 2 states away,and in november,their 3 month warranty runs out by the time you can get it on the lake,so now I'm stuck with the bill for a motor that most likely was trouble when they sold it to me,anglers choice marine

[pmgoffjr]

Could be something easy like garbage gas.
At least it doesn’t have a hole in a piston.

[mdtritn21]

You want the center of the prop shaft 3.5" below the lowest point of the hull not the cavitation plate. http://www.bbcboards.net/showthread.php?t=62660 Look at the drawing here.

[1pabassman]

Right now it is set at 3 1/4,but heres what I found,the motor checked perfect,but I had to change cranking battery because I was using a dc group 29,so I put a 1000 mca cranking in and put a seperate dc battery for all my electrics,the biggest move was,I spoke for an hour with a motor tech at mercury and we went through all the specs and he found that I should be running a14 to 14 3/4 dial by 17 pitch prop on this motor,I have been running a 21 an 23 p lazer 2 prop which after he looked the numbers up he discovered both were only 12 3/4 dial props and neither prop should be on the motor because they are made for outboards 135hp an less so due to the fact I dont have that kinda money I ordered a 14 1/2 x 17 p solas titan 2 prop which after discussing it with the tech he said that prop is almost the identical twin to the tempest prop,so I will update after I recieve it an test. Until then I'm using the 23 lazer just to get around slowly.