Starcraft SS201

[dozerII]

Okay I'm coming back with everything fixed and running at it's best. 1986 StarCraft SS201, 1989 Mercruiser 4.3 LX 205 Hp
1.81 GR Alpha, Boat weights 2300lbs. Running at 4600rpm at 37mph gps. I have the trim adjusted as per Merc specs
21.5" . In a straight run the prop will blow out before I can get the bow up much at all with the trim, in turns I almost have to trim all the way down to prevent blow out. There is another member here on Iboats with the same boat with a 140 OMC he can get 42 mph no problem. Where do I look, I'm pretty much lost here.

 

[steelespike]

Re: Starcraft SS201

delete

 

[steelespike]

Re: Starcraft SS201

OK so this setup is new to this boat or at least didn't start out in this boat. My first thought is the drive is mounted too high
Or something on the boat is disturbing the water near the prop.
Is the prop in new condition?Perhaps the wrong prop what is the diameter?
Your numbers indicate your slip is very high 28% at a more normal 12% your speed would be about 45 .
I would think that boat would hover around 50 carefully setup and lightly loaded.

 

[dozerII]

Re: Starcraft SS201

OK so this setup is new to this boat or at least didn't start out in this boat. My first thought is the drive is mounted too high
Or something on the boat is disturbing the water near the prop.
Is the prop in new condition?Perhaps the wrong prop what is the diameter?
Your numbers indicate your slip is very high 28% at a more normal 12% your speed would be about 45 .
I would think that boat would hover around 50 carefully setup and lightly loaded.

Thanks for the reply SS, the boat came with this set-up , but the motor was replaced. I did a complete refit of the hull over the last year right down to the hull, floors foam the works. there is no dents in the hull or deformaties. I'm really at a loss.

 

[jestor68]

Re: Starcraft SS201

What prop are you running?

 

[jestor68]

Re: Starcraft SS201

[QUOTE=dozerII;4295073 I have the trim adjusted as per Merc specs
21.5"

I don't understand that statement.

 

[dozerII]

Re: Starcraft SS201

What prop are you running?

I'm running a Mercruiser prop 14 1/4 X 21 The trim adjustment I referred to is how far it can be trimmed up safely at WOT.

 

[steelespike]

Re: Starcraft SS201

Check the timing both that it is set right and is advancing as it should.
So are you saying they say to not trim beyond 21 1/2 Degrees? I not acquainted with what degree is usual.
So is the prop old,new al. ss. As props age the diameter actually can get worn undersized.
You might check for a spun hub.Not likely but as strain increases in a turn it might spin and perhaps just the right conditions in a straight line.Grasping at straws here.If the prop is old I think that a new prop will resist venting better.,and a 4 blade even better.
Perhaps you have a friend that will let you borrow a known good prop to test with.
Is there a whale tail on the out drive?

 

[dozerII]

Re: Starcraft SS201

Check the timing both that it is set right and is advancing as it should.
So are you saying they say to not trim beyond 21 1/2 Degrees? I not acquainted with what degree is usual.
So is the prop old,new al. ss. As props age the diameter actually can get worn undersized.
You might check for a spun hub.Not likely but as strain increases in a turn it might spin and perhaps just the right conditions in a straight line.Grasping at straws here.If the prop is old I think that a new prop will resist venting better.,and a 4 blade even better.
Perhaps you have a friend that will let you borrow a known good prop to test with.
Is there a whale tail on the out drive?

The motor has thunderbolt ignition so no advance plates. I will have to get a timing light that will give me total advance. The prop is an aluminum in new condition with no damage, no whale tail or trim tabs. I did have issues with how the engine was running but believe I have those fixed.

 

[dozerII]

Re: Starcraft SS201

Any one have any suggestions?

 

[Paddichuck]

Re: Starcraft SS201

DII - sorry to read about your troubles.

I suspect a 4 bladed prop might help but would not really be addressing your problem.

Do you have any transducers near the centreline that might be causing turbulence?

How high is the anti ventilation plate above the hull?

Are you sure about the trim angles?

If you don't have something disturbing the water near the centreline of the hull my best guess would be the anti vent plate is too high or the trim angle is too steep.

If you were referring to our V5 SS201 above its actually a 3.8L 185 hp OMC swinging a 14 x 19 - 3 bladed prop (have both SS and Al props with same specs) and light loaded we see 40 mph at about 4200-4400 rpm with +/- about 1 mph depending on which prop and load. That is why I guessed your 4.3 at 205 HP might deliver a couple extra mph if set up nicely.