Is the motor height going to be an issue?

[S.E.R.E.NITY NOW]

Theres a few different homemade versions of risers...a few on this site, seen in the search.
Have you been in this boat yet?

No I haven't. I've been working on it the past couple of months to get it ready for the season. Thing is if it's not right I don't really have the experience to know it's not right or how it should be operating. Trying to start off with the industry standard and go from there. Everything I've watched or read says it's too low. Have to test it I guess and see if how it performs to get a baseline.

 

[MDCrappie]

That's what I'll end up doing if it needs to come up more. The adjustability of a jack plate would be nice but I really don't want to move the motor back any further.

Did that put the cavitation plate level with the transom or slightly above?

I don't remember exactly where it sits now and the motor is in the shed. What I did though was raised the motor 1/2" at a time. Got to the point where I needed raise it above where the clamp would not hit transom so I made that plate. I then raised the plate 1/4" at a time (securing it with 4 screws into transom) and did test runs. When the motor started to "blow out" I stopped and took the bracket back down to the last spot I had it. Then I bolted the bracket thru the transom. IIRC my top speed went from 10 or 11 up to 14+mph.

 

[Bailey Boat]

Do you realize that the jack plate also sets the motor back?? Almost un avoidable....

Check Tiny Boat Nation for a "Transom Plate".... https://tbnation.net/products/transom-mounting-bracket

If you order make CERTAIN of your existing transom thickness.....

 

[TriBull]

Love having an adjustable jack plate on my 12” StarCraft. Easy to make height adjustments to get it right, handles great, tremendous top speed, and leaves lots of room on the transom for my ladder and boat hook. I have a 9.9 Yamaha and use a short tiller extender for steering.

 

[Zum]

No I haven't. I've been working on it the past couple of months to get it ready for the season. Thing is if it's not right I don't really have the experience to know it's not right or how it should be operating. Trying to start off with the industry standard and go from there. Everything I've watched or read says it's too low. Have to test it I guess and see if how it performs to get a baseline.

Looking at your first post, Im thinking you might be a big guy?
The riser should be your best bet but without using it hard to say how high.
With where its at no big problems will occur, just know it deeper in the water.

 

[FuzzyGrub]

Solid advice all around. Thank you.
I do plan on running it first before I make anything too permanent. My issue is my lack of experience. I'm not entirely sure what I'm looking for or feeling for to say yes or no as to how it should be set. That's why I was looking to put it at the industry standard and go from there. The 1" I raised it with the square tubing is easy to try out and change and see what difference I notice. I am a little worried the clamps are too close to the top of the transom.
Here's how it looks raised 1" from where it was. Still 1.5" below the transom if going by a straight edge along the hull.

Agree with Thill, test it. It is probably going to run fine with the 1" blocks. Going to flush may pick you up some mph, but might cause problems when turning. Many mfgs recommend 1" below. My 10HP Sportwin sits like that on both boats I've used it on.

To go higher than the 1" blocks, can you just use the transom thru bolt mounts?

Get a Tiny Tach or equivelent to record WOT rpms, along with something for GPS speed,

 

[S.E.R.E.NITY NOW]

So I got the boat out today to test things and do the break in on the 9.9 here's how it performed with the 1 inch lift. So the cavitation plate sits 1.5" below the transom. Just me in the boat.

Could not get on plane unless the motor was trimmed all the way down.

Steering was heavy but not unmanageable and it wants to pull to the right. Trim tab adjustment?

No water splashed in from the motor, just from my transducer I had mounted to low was throwing a rooster tail when on plane.

When on plane it maxed out at 20.9 MPH but it took about 6-7 seconds to get on plane. Not sure how that compares to other boats with similar characteristics.

I have a baseline now at least so if I make changes I guess I'll know I'd they're an improvement or not. I think I'm going to raise it up the next 1.5"

Is there any benefit to moving the engine back like a jack plate would do?

 

[Still Afloat]

If you are getting 20 mph with a 9.9 it’s probably Ok. Any idea what RPMs it was running at WOT?

Jackplate manufacturers claim that moving the motor back will get the prop in cleaner (less turbulent) water and increase performance. There is probably some truth to that statement.

The only reason that I’m trying to avoid a Jack plate is the cost and more important, the weight of the outboards that I’m running. The 25 jet is about 205 lbs and the 25 Zuki is 175 to 180 lbs. Moving that weight further back on my 1448 is not ideal.

I also have a 9.9 Suzuki that has been modified to a 20hp. I’d guess that your 9.9 is similar in weight, maybe a 100 to 120 lbs depending on options. Anyway, it would not be an issue to move this motor back a bit. Actually, I prefer the lighter motor but, it’s just fine with a 1” shim. Spending a wad of cash for jackplate seems like a poor return on the investment for a couple of mph at wot.

I might have to go with a jackplate if the Zuki 25 prop doesn’t like the same hole heights as the Merc 25 Jet. Of course this would require pods and probably a few other things. It’s crossed my mind more than once to sell both 25s and just keep it simple.

 

[S.E.R.E.NITY NOW]

If you are getting 20 mph with a 9.9 it’s probably Ok. Any idea what RPMs it was running at WOT?

No I don't have any way of measuring RPM.

 

[FuzzyGrub]

Yes, adjust the trim tab to compensate for the pull. Manual should tell you which way to adjust.

Raising the motor might help a little with the planing time, might not. Mostly it will be a gain of a few mph of top speed.

A lower pitch prop will help with planing time, but need a tach to see where your WOT rpms are now. The lower pitch prop will take some speed off of the top end though.

 

[Still Afloat]

Your boat looks good!

 

[S.E.R.E.NITY NOW]

Yes, adjust the trim tab to compensate for the pull. Manual should tell you which way to adjust.

Raising the motor might help a little with the planing time, might not. Mostly it will be a gain of a few mph of top speed.

A lower pitch prop will help with planing time, but need a tach to see where your WOT rpms are now. The lower pitch prop will take some speed off of the top end though.

It's never going to be a fast boat. 20mph is more than enough for what I'll be using it for. It would be nice to get on plane easier though. I can drop it down to about 15mph and stay on plane. Anything below that it will drop off.

 

[S.E.R.E.NITY NOW]

Your boat looks good!

Thank you. I'm trying not to over do it with things I don't need. Not a lot of space to work with but it needed a few things to make it functional. A casting deck would be nice but I'm going to run it like this for this season. Having the flat floor is already a bonus.

 

[S.E.R.E.NITY NOW]

If you are getting 20 mph with a 9.9 it’s probably Ok. Any idea what RPMs it was running at WOT?

Jackplate manufacturers claim that moving the motor back will get the prop in cleaner (less turbulent) water and increase performance. There is probably some truth to that statement.

The only reason that I’m trying to avoid a Jack plate is the cost and more important, the weight of the outboards that I’m running. The 25 jet is about 205 lbs and the 25 Zuki is 175 to 180 lbs. Moving that weight further back on my 1448 is not ideal.

I also have a 9.9 Suzuki that has been modified to a 20hp. I’d guess that your 9.9 is similar in weight, maybe a 100 to 120 lbs depending on options. Anyway, it would not be an issue to move this motor back a bit. Actually, I prefer the lighter motor but, it’s just fine with a 1” shim. Spending a wad of cash for jackplate seems like a poor return on the investment for a couple of mph at wot.

I might have to go with a jackplate if the Zuki 25 prop doesn’t like the same hole heights as the Merc 25 Jet. Of course this would require pods and probably a few other things. It’s crossed my mind more than once to sell both 25s and just keep it simple.

Jack plates are expensive but I'd like the adjustability. For now I'll live with it and run it some more. See how it does with a second person in the boat. This motor weighs 84lbs but I have the tank and storage bin and a small 20ah lithium iron battery back there too. It might balance out better with someone else up front but I'm by myself for the most part.

 

[MDCrappie]

So I got the boat out today to test things and do the break in on the 9.9 here's how it performed with the 1 inch lift. So the cavitation plate sits 1.5" below the transom. Just me in the boat.

Could not get on plane unless the motor was trimmed all the way down.

Steering was heavy but not unmanageable and it wants to pull to the right. Trim tab adjustment?

No water splashed in from the motor, just from my transducer I had mounted to low was throwing a rooster tail when on plane.

When on plane it maxed out at 20.9 MPH but it took about 6-7 seconds to get on plane. Not sure how that compares to other boats with similar characteristics.

I have a baseline now at least so if I make changes I guess I'll know I'd they're an improvement or not. I think I'm going to raise it up the next 1.5"

Is there any benefit to moving the engine back like a jack plate would do?

Classic symptom of motor mounted too low. Proper way to correct is to raise the motor. When I bought my Carolina skiff 16 you could not take your hand off the steering wheel at any speed above idle. Can't believe 2 different owners lived with this for 20 years. I raised the motor (40hp) 3 holes and now I can run hands free up to WOT and the boat tracks perfectly straight. Better throttle response and no blow out. It's a bolt on motor and went from top hole to bottom hole. I question as to how dealerships can be so clueless. The boat runs 3-4mph faster and zero steering issues. I even added a piece of cove base molding to stop waves from coming over transom when fishing. I felt it was actually dangerous to drive before I moved it up.

 

[Stinnett21]

To decrease time to plane, move the trim pin on your motor closer to transom.

 

[thill]

20.9 mph with a 9.9 is very good, in my book.

Go fishing! USE the boat and stop worrying.

AS YOU GET TIME, do a few things...

1. Tighten the steering tension a bit, if it pulls hard when you take off.
2. Loosen the steering tension if it's just hard to steer.

3. Adjust the trim tab above the prop on the cavitation plate to reduce pulling to one side.

4. Buy a tiny tach off Amazon to find out your RPM. They are maybe $15.

5. Once you know your RPMs, you may want to go down a prop pitch or two to get on plane faster, let your engine breathe easier and run at the recommended RPM at WOT... but ONLY if it needs it.

Congrats, and ENJOY your boat!

 

[LaqueRatt]

I don't know much, but I'm surprised a 9.9 will even get that boat on plane and 20+ mph seems mighty impressive. I don't know what more you could want really. If you desire more, you probably want a bigger motor.

 

[flatheadsteve]

20mph is moving with a 9.9 in that boat. A tachometer would tell you if and how much you could potentially change prop pitch. You can play around with where you have the trim set to see if that helps the time to plane any.

 

[Zum]

Like others have mentioned, your speed is good.
Getting a cheap induction tach (tiny tach or knock off) is a good investment, tells your hours use, rpm and knowing your rpm is the only way to pick the right prop.
Nice looking boat, Id say your in the ballpark for sure, speed is good, planeing time wasnt terribly long. A lower pitch prop or a 4 blade prop would plane you out faster and most likely keep you on plane at a slower pace but you will probably loose some top end. A tach will help you fine tune, easy to hook up, wrap 1 wire around your spark plug wire and find a ground for the other wire, done.