180 df90 2004 hull & engine. Anyone got this dialed in?

[native77]

New to me to me clean boat. ;It's a DC but looks to be the same hull as the CC

Engine is nearly as high as it can go, cav plate still buried about 1" under water at 6000 rpm 32 mph.

Engine height too low, am probably getting a fixed height bracket to raise it another 1.5" +,-

Seems to want more pitch, current prop is 13 7/8 omc/brp prop

i am thinking go to a zuke 14x20 estimated lower rpm by about 500 which would bring max rpm to 5500 which is zuke stated max for that motor.

this is my first 4 stroke, lovin the boat.

any feedback from CC or DC owners on the engine height or prop recommendation a are welcome


It will likely never cross the inlet as it was added to the family as a river toy ...Indian River..mostly inshore dash and cruise ...her Morgan big sister is in the back of the shot..

[acdaddy0]

Native it looks to me like it's too high already! It could be sucking air or cavitating causing high rpm due to less bite on blades . I have a 13 3/4 x17 on my two stroke 115 hp puts me around 5800 and 40 mph. Does it rev high when you turn? I would lower it to where stick is just under plate. Should give you better bite , lower rpm . If it is sucking air you will have higher pms and possibly lower speed. Maybe lower it a hole at a time and see what happens that way before you jack it up more with plate. Can you trim it up much before it revs out? I can't imagine a 20 p on a 90 hp . I bought a spare prop at 19 p and it's a little too much for my 180 cc. Lowered rpm to 5000 and speed fell off about 3 mph. Also less torque.

[acdaddy0]

I don't have a really good pict but mines in the next to last hole from top. Still sucks air a bit in hard cornering but works well. You sink it too low and speed will suffer. Also I think there is a difference between a four and two stroke prop. I believe it is the actual surface area of blade being more for four stroke. That being said I'm pretty sure the one I use is actually for a four stroke but it works great.

[native77]

acdaddy
Thanks for the reply.
The df90 is definitely too low as the cav plate is buried under water when trimmed for best speed at wot - straight, turns all the time.

I see you have both trim tabs and a hydrofoil, both lift the stern at speed.  Not sure if you added them but someone tried to get the stern lifted.  I will go to a hydrofoil is no other options solve this, but likely I will raise the motor with a jack plate.

General,rule is for every foot the engine is mounted rear of the keel raise the cav plate 1" higher than the keel, some say 1/4" for every inch.  Because of the cutout forward of the motor, this hull would need the cav plate 1.5-4.5 inches above the keel.  The most I can get is about 2.5" and the cav plate is still 1" below the water.  

I was was hoping I could find a seapro owner with a df90 on this hull with it dialed in.

As far as the prop, the df's have a 2.59:1 gear ratio, I think your engine is 2.0:1 so the prop speed on the df's are about 30% less at any given rpm meaning the df's would need more pitch. 

I did a lot of research on seapro before purchasing, like the boat a lot so far, handles nice, and guess it will only get better once it's dialed in.

again, thanks for the response.  

[T-Topless]

I have the 180cc with a Yamaha 200 2-stroke. Same cutout in the hull.

I put a 4" setback jack plate on it and raised it a lot.
WOPening throttle, when she hits about 5,000 RPM (trimmed up even more), it feels like it shifts gears and jumps to 6,000RPM and jumps to 60-67mph+ (depending on load). Couldn't run it this fast without the Smart Tabs ...

[acdaddy0]

I had just finished installing trim tabs, the level is still under it and hadn't takin doel fins off yet. Was not pleased with the hydrofoil and didn't really need hole shot lift but get it if I want with tabs. I have a short shaft johnson , 20". Yours may be 24" . 

[acdaddy0]

Ttopless may have the best answer! a jack plate would let you move it around to exactly the point you want without pulling bolts and jacking up etc.

[native77]

I knew it had to be raised.  Went to bobs machine shop this mornin.  Got the 4" plate with up to 5" lift. Installing now....without a hoist.  Should be fun. 

[native77]

Southern cross , I'll keep this updated in the event anyone can learn from my mistakes.  That's boating.  rofl


I will will first see if I can get plate level with water flow at cruising speed/rpm, the re re re evaluate. 
Btw love the name 

[acdaddy0]

Yes, if your not changing and possibly making mistakes your not learning! I've never looked at my cav. Plate while underway. Will tommorow. Keep us posted and Picts!

[native77]

Shaft length is 20". I found the original sell sheet for the cc and it states the hull is designed for a 20.  This boat was from a dealer chatlee in NC. Silicone sealant not 5200 on the mount bolts. I can see they either went the safe way for liability or just simply didn't  know how to set it up.  Maybe is was seapro?  

Any one know if these cam from factory rigged or done at dealer in Chatlees case?  Just curious. 

Just  finished with the install, galled one of the nuts, was getting dark.  Connected up 200' of air hose to get the die grinder to cut the galled bolt nut off lowest (top) hole is now at the 2" above keel, which was the highest I got before. More pics maybe tomorrow. 

[acdaddy0]

I'm not positive but pretty sure all were dealer rigged with different brands of motors. You'll get it , hard work equals results!

[freezerfiller]

Sept 24, 2014 14:33:32 GMT -6 acdaddy0 said:

really need hole shot lift but get it if I want with tabs. I have a short shaft johnson , 20". Yours may be 24" . 

notworthy notworthy I heard about those tabs, but I had no idea!!! ....Can I borrow your ruler?

[T-Topless]

Yes, the 180cc is supposed to have a short (20") shaft motor. The 190CC got a long shaft.

The only problem with raising the engine is if you run the boat in rough seas, as the engine will pop out going over waves, so you'll have to be careful on the throttle if you do this.

Personally, I don't think 90HP is enough to warrant a jack plate on this boat, but that's up to you... 32MPH is pretty good with 90HP on a 1,500lb hull with 15deg deadrise and no pad.

[acdaddy0]

Dirty minded Freezer!! Didn't even see that one coming! Ha another one!

[acdaddy0]

Sept 25, 2014 5:20:11 GMT -6 T-Topless said:

The only problem with raising the engine is if you run the boat in rough seas, as the engine will pop out going over waves, so you'll have to be careful on the throttle if you do this.

Personally, I don't think 90HP is enough to warrant a jack plate on this boat, but that's up to you... 32MPH is pretty good with 90HP on a 1,500lb hull with 15deg deadrise and no pad.

This is how you do it if your married. First you get a  hydraulic jack plate and install because you hurt your back moving motor around and had to take a day off work. Then later on down the road you'll convince wife that a 150 hp would save on gas due to less rpm and you could get a good trade in for that one. Convince her it would save you in the long run!! Then your goons have no choice but to get trim tabs to level out torque issues.  VIOLA,!  You got a kickin boat that hauls the load and has all the control that "I" love!  

[T-Topless]

That's funny - married 23 years here ... w

Wanted to put a 250 on the boat, but wife put her foot down on that one (so I built the 200 up some)

[native77]

Thanks for all the help guys.

32 @ 6100 , but I know there is more through getting the set up right. 4200 is about 22mph.  

Rough weather is what her sister is for, the Morgan, it's built like a tank.  The 180 DC will likely never cross the inlet.  

I only want to get the cav plate at the water line and benefit from the lowered drag and hoping to get a bit of stern lift from the cav plate hydrofoil effect.  Only then can I get it propped right.  If it's turning 600 rpm above spec, she can handle a bit more pitch. Maybe get it to 25 @4100 ish.  

My my experience is small diameter props blow out much easier that larger diameter, these lower units use 14" props and prop speed is lower than most due to the low gearing.

Here are a few pics of the install, no hoist.  Like on mythbusters, don't try this at home.


Rested the skeg on a cradle, 3 straps, one to each stern hook and the pivot tube, one across the entire stern.  Block the trailer wheels, got the engine secured in all 4 directions.  Used 8" 3/8 bolts on one side to " gently push the engine back while using trim to rock the mounting bracket 1/4-1/2" at a time. Voila there is room to mount jack plate, 5200 and bolt one side in, leave the bolts to engine loose, remove the 3/8 bolts for other side, rinse and repeat.

[acdaddy0]

I'm not helping just making comments while you work! I'm enjoying your work , hoping that I'll learn from this . It goes against what I THOUGHT I knew about the cavitation plate lining up with the bottom of the boat. I would have lowered it as seeing first photos. Keep the posts and Picts coming . Can't wait to see what happens. I love seeing someone getting in there and gettin it done!!

[acdaddy0]

Intrigued by this , I researched measurements and proper placement on paper. Also watched videos, I now believe placement is unique to every boat. Some with pads and the vee's. Liked this video. Also a great song.