Limited to 9.9hp

[JimS123]

Re: Limited to 9.9hp

The angle of the pic might be deceiving, but it sure looks like a long shaft motor on a short shaft transom. The "cavitation" plate is the one above the prop - that's where the measurements are made.

The mounting hole is at the bottom of the transom bracket. If that's a photo deception as well, tilt the motor up and use a u-bolt through the center of the transom bracket. ALL motors can be bolted on - some just require a little ingenuity.

 

[Scott Danforth]

Re: Limited to 9.9hp

its a short shaft motor from the pic, however the transom looks like it is cut down short. I agree, a side shot showing the keel and anti-cav plate relationship would help.

 

[dkonrai]

Re: Limited to 9.9hp

its a short shaft motor from the pic, however the transom looks like it is cut down short. I agree, a side shot showing the keel and anti-cav plate relationship would help.

+1 that motor looks like its sitting waaaayyyy low.
dino

 

[slowleak]

Re: Limited to 9.9hp

The AV plate is 3/4" above the bottom of the boat.
The transom measures 16 3/4" tall, or 15 3/4" vertical measurement, and the motor measures 15" from the bracket to the top of the AV plate.

I've got three props, one is the two blade it came with, the other a 9x8" three blade off a newer 9.8hp Merc, and a 9 1/4" x 7 with no other markings that came from a junk 7.5hp a buddy had.
All have new bushings and were serviced by a local prop shop.

I did loan the 9.8hp to a buddy who wanted to test run a 12' flat bottom that weighed only 98 lbs, with him at 137 lbs and nothing else in that boat it flew, but I'm not 137lbs and never will be.
Keep in mind I do have the 16' version of this same boat, its does the same thing, but is slower overall.

What do you think would happen with the two blade prop and a hydrofoil?
I've left the two blade since it seems to move more water, or at least make a bigger wake or throw more water behind the boat. The three blade moves water but if I go full throttle too fast it just loses grip and revs.

The bottom line is that the 14' boat is the best choice overall, its a deep 14' boat with a flat bottom, going to a 16' doesn't add much capability, only more drag due to the longer hull and slightly wider beam.
Due to the partial bow plate on the 16' they both have roughly the same amount of room inside. The first 22" of the 16' is closed off with a bow plate with a chunk of foam flotation beneath it.

I've got the chance to buy a 15hp Honda motor, (marked as a 9.9hp), but am concerned about its 111lb weight.
But I'm thinking that the low end grunt of a four stroke may help this boat?

 

[steelespike]

Re: Limited to 9.9hp

Few small 4 strokes have low end grunt compared to a 2 stroke.Being a 15 it will blow the doors off your 9.8.
But I don't think it could match the OMC 15 and its 77 lb weight. and 2.42 ratio.
The 15 is va relieved 9.9 they are esentially the same motor and use the same props.
the 15 and 9.9 come with the same standard the 15 has a max rating of 7000 the 9.9 before 89 has a 6000 rpm max
You need to run a prop that is less than the 8" the 9 1/4 X 7 is a good bet.and try the doelfin.
Opinions say the Doelfin is hands down the best choice.
I would point out that a 7" prop for the OMC 9.9 and 15 is a 10" diameter.

 

[JimS123]

Re: Limited to 9.9hp

Four strokes are dogs out of the hole. The 2 strokes are the ones with low end grunt. Besides, you need to cut weight, not add more.

If it were available, a 4-blade prop might help some. The 3 should be better than the 2.

I can't help but go back to your 1st post, saying it didn't work with a 110# person at the helm.

You have an equipment problem! Without seeing a horizontal pic from the stern at keel level I'm afraid we can't be much more help. While you're getting that, buy a tiny tach and also report your WOT rpm.

 

[roscoe]

Re: Limited to 9.9hp

Try a different measurement.

Measure from the top edge of one of the prop blades, upward to the bottom of the hull.

This should measure .5 to 2 inches.

 

[Scott Danforth]

Re: Limited to 9.9hp

I would almost consider ventilating the prop to get out of the hole

 

[dkonrai]

Re: Limited to 9.9hp

iboat prop for a jonnyrude 9.9/15
Solas Amita Aluminum Boat Propeller #2113-093-10 for Johnson 9.9 - 15 HP Outboard 1974 - 2005 9.9-15 HP, 2-Stroke - iboats

 

[64osby]

Re: Limited to 9.9hp

My '57 10 hp pushes my 14' Lone*Star to 15mph with a 500# load.

You have an issue with the motor or hull IMO.

 

[reelfishin]

Re: Limited to 9.9hp

Those older Starcraft hulls were heavier than their newer counterparts, so the hull weights you mention sound about right to me.
After reading through these posts I had to go out back and weigh the 1973 Starcraft 14' hull I've got here and mine weighs 294lbs bare hanging from a competition scale meant to weigh motorbikes. The max weight rating on this one is 940lbs, with a max hp of 20hp. The transom looks identical to the one shown buy the original poster here. The transom is not cut down, nor does the one shown here as the original aluminum cap is still in place.
For years I ran a 15hp Johnson on a 15' mod V hull with stick steer and full floor and three seats. I got 17 mph on the fish finder, when I added a hydrofoil, I believe mine was a Stingray brand, I got 23-25mph. This was long before we all had GPS to go buy.
That boat was heavy, probably well over 800lbs empty.
I can't say how accurate the fish finder was but by the seat of the pants feel goes it was pretty quick.

I'd get rid of that two blade prop and go with at least a three blade model and add the hydrofoil and see what happens.
If it were me, I'd sell that 9.8hp and find a good OMC or even a Yamaha.
Forget the four stroke, their still way too heavy for your boat.

 

[slowleak]

Re: Limited to 9.9hp

My '57 10 hp pushes my 14' Lone*Star to 15mph with a 500# load.

You have an issue with the motor or hull IMO.

I've been all over this hull, there is no issue with the hull, it looks as good as brand new all over. I even went out and pulled the seat foam out again to check the weight and each foam block weighs 4.66 lbs. and 5.2lbs which seems in line with the 1.5 lbs per cubic foot weight listed for expanded poly styrene. I'd guess that there's between 6 and 7 cubic feet of foam total beneath the two rear bench seats. The front bench has no foam, just wood over a metal frame.
There are three hardwood bench seat panels, weighing 14, 22, and 27 lbs. each They apear to be either red oak or some sort of tropical wood like teak.

The motor is mounted with the av plate 3/4" above the bottom of the hull checked with a straight edge. The motor attains 4900 rpm with the factory two blade prop, 5400 rpm with the 9 1/4 x 7p prop on the boat. I had a local shop test run the motor in a tank with a test prop and the motor can attain the rated rpm for the test prop/wheel used.

I've got a box of used hydrofoils here, most are either Doelfins or Stingray brands. The Stingray is the smallest of all of them.

 

[Nuaticocat]

Re: Limited to 9.9hp

Can you post a pic of the hull? From the way you describe how it runs, sounds like the hull is a displacement type hull. Has it ever been on plane? I had a 14 fisher v hull, with a 25 merc. Ran a 9.9 Johnson on it for a little while : 9.9 performed the same as the merc, just not as much top speed. Even with 500 lbs of old guys in it.

 

[colbyt]

Re: Limited to 9.9hp

Slowleak, something is not adding up here. How wide is your boat? How heavy the OB?

I have a 14/48 (67" beam). With 600 pounds of lard (300 front and back), a class 27 battery in the back, 42 lbs of OB I always have enough freeboard to feel safe even if I am standing at the transom. Now I have no expectations of planing but 3.5HP is the limit on one of the lakes I fish and the other is 5; both are no wake. We manage to cruise along just fine.

 

[JimS123]

Re: Limited to 9.9hp

Can you post a pic of the hull? . Has it ever been on plane?

He said it won't plane with a light load and a little kiddie driving it. We all know there is an equipment problem. When the pic is finally posted, we'll all say..."there's your problem".

 

[slowleak]

Re: Limited to 9.9hp

Here's two pics I got from the last owner when I bought the boat, the green carpet is gone, as are the oars. I also swapped out the 6 gallon tank for a 3 gallon tank.

The hull is bare, as it was when new. Who ever owned this took care of it or had it packed away for many years unused.
I'm not 100% sure if its a Sea Farer, Sea Scamp, or Sea Star model. I scanned a page from the brochure that came with it that called it a Super Star 14 but the color didn't match.
The specs seem to be the closest to any of the Starcraft models.

Basically its got a 57" beam with a 50" transom. Its deeper than most 14' boats and heavier gauge than most I've seen.

The bottom is basically flat with a slightly rounded bottom at the stern.
To give an idea of how deep this hull is, if I stand up between the last two bench seats, the gunwales hit my at about the knees, or about 23" tall.

I've also got a chance to pickup a 20hp Mercury, I think its a 1970 or 71 model but that too has a two blade prop. The guy who owns it currently runs it on an almost identical boat and claims he gets over 30mph out of it but he's maybe 120lbs tops. The motor sounds good but stalls when you back the throttle all the way off.

I've watched him run that motor on his boat and it flies, but he runs it with a tiller extension from the middle seat. Its way heavier than my 9.8hp. He's asking $400 for the motor and its got a new water pump, new prop hub, and new spark plugs. Its got 145 psi on both cylinders.
When his boat takes off from a stand still, it sinks low in the water then pops right up on plane within 30' or so. Once on plane it just takes off. Mine right now sinks much like his does but never pops up on plane.

 

[JimS123]

Re: Limited to 9.9hp

Those pics can't help us diagnose the hull / motor problem.

All I can say is my Sea Nymph looks quite the same as yours, and she runs perfect with a 9.5 and 4 people aboard.

What's the serial number of your motor?

 

[slowleak]

Re: Limited to 9.9hp

Here's the only bottom shot I have here, the boat is in a dark barn with no light right now, and with 8" of snow outside, its not coming out for a while I guess.
There is no dents in the hull, anywhere, the motor is mounted at the proper height, and I've tried raising it as much as 2" above where its at in the above pic but putting a 2x2 chunk of wood under the bracket. All that did was cause the prop to churn water real bad, it acted as if it were in shallow drive position all the time.
When in the water, with two persons and all gear, if I look down at the drive the AV plate is just slightly below the surface of the water, that never changes, even when I give it gas, the water level over the AV plate is still about the same, the prop seems to evacuate all the water and the boat level just gets lower in the water.
I've had other boats that did this but never one that didn't recover as it started to move.
From the drivers seat its a bit unnerving to look to either side or behind and see a wall of water following the boat a good 6" over the gunwale level.

I think its got more to do with the prop vs the size of the hull than the shape of the hull.

I do think a hydrofoil may be an answer but I'm not sure yet if I want to drill any holes in the motor or the hull yet.
I'd rather find either a better solution or another motor.

 

[steelespike]

Re: Limited to 9.9hp

I'm convinced the boat is sound. With your full load I don't think you can solve it with that motor.
Also the boat is small. A Starcraft SF14L is bigger at 14'3" 63" transom,68"bream,5 (p) 700 lbs., max weight 1020.25HP.
Your boat is 700lbs I think that is supposed to include the motor.
I think you have a chance with a OMC 9.9 or cheat with a 15.The 9.9 is rated for 6,000 rpm prior to 89.
89 on 6500. That means that when going to a smaller prop if you get it to plane you may get a little more speed.
There are 7" props and also 4 blade props available and SS as well.

 

[JimS123]

Re: Limited to 9.9hp

Beautiful boat...awesome condition. The trailer is repainted -- is the boat original paint?

Maybe its just a matter of the fact that your requirements are exceeding the boat's capabilities.

Personally, I customize everything. I'm not satisfied until I've drilled dozens of holes and mounted dozens of new parts. As long as the holes have a bolt in them I'm happy.

I have 2 tiller tinnies with a Doelfin on both. With all the weight aft for me its a requirement. Some say the fin is a bandaid...I say its optimizing performance with an optimum layout.