Prop question

[dnyhuf]

I have a 1992 cajun 1900 tournament series w/1992 johnson 200gt running a 4 blade ss 133/4 x 24 prop, 5500 rpm, 50mph. seems slow out of hole, should top speed be better also? any suggestions?

 

[steelespike]

Re: Prop question

Not an expert but I can tell you generally speaking a 4 blade will hold down your top end.Your rpm is right at the 200s hp rating.200 @ 5,500.A 3 blade would give you a little more top end.Can't tell you where your rpm would be.
I'm guessing that a 24" prop on a 19 ft boat won't have great hole shot.
Though again not an expert.Some one should be along with more specific info.

 

[dnyhuf]

Re: Prop question

Should I drop to a 3 blade 23" perhaps?

 

[dnyhuf]

Re: Prop question

bump

 

[dnyhuf]

Re: Prop question

bump

 

[Dhadley]

Re: Prop question

You're at 18-19% slip. That's not good at all. You should be spinning a small diameter 24 a bunch more than 5500 with a 200 GT. Low top speed, low top rpm and a slow holeshot all indicate the motor isn't running right. If it's indeed hittin on all 6 then check your top timing. If it were mine I'd put it on a test wheel to make sure the motor is doing what it's capable of.

After we know the motor is capable we'll look at set up. Jackplate? How's the balance? Do you need a lot of positive trim to carry the nose?

 

[dnyhuf]

Re: Prop question

Didn't seem right, I will follow your suggestions and get back to you with results. Don't have a test wheel, will take it to a shop. No jackplate, balance? , some vibration, especially at low RPM. Yes a lot of positive trim.

 

[dnyhuf]

Re: Prop question

Would Joe Reeves instructions for WOT timing out of water suffice?

 

[Dhadley]

Re: Prop question

That should get you in the ballpark or at least tell you if it's way off.

 

[Dhadley]

Re: Prop question

Couple of other thoughts -- when you advance the throttle the timer base is moving, right? And without a jackplate I'm not sure you'll get the set up right on that boat.

 

[dnyhuf]

Re: Prop question

Couple of other thoughts -- when you advance the throttle the timer base is moving, right? And without a jackplate I'm not sure you'll get the set up right on that boat.

You have lost me with the jackplate comment. Would you please explain?

 

[Dhadley]

Re: Prop question

That boat needs help to carry the bow. The offset will help change the fulcrum or balance point. It also will help reduce gearcase drag. Getting the most out of that rig will also require a bigger diameter prop. The jackplate will allow that.

 

[dnyhuf]

Re: Prop question

Timing did not seem off, but took it to a shop to have it gone through. Tech said all looked ok. Told him about issues discussed in this thread, and that a jackplate was not in the cards at this time. He gave me a prop to try, and asked that I post results here for feedback. So here it goes.

1992 Cajun 1900 Tournament = 1350lb., 40gl. fuel, 1 person
1992 Johnson 200GT
Early Raker 141/2x22 three blade
WOT = 5800 rpm @ 59MPH

And here is what I originally posted.
"I have a 1992 cajun 1900 tournament series w/1992 johnson 200gt running a 4 blade ss 133/4 x 24 prop, 5500 rpm, 50mph. seems slow out of hole, should top speed be better also? any suggestions?"

 

[Dhadley]

Re: Prop question

There ya go! Right around 11%. Amazing what a little diameter and some rake will do! The Cajun can usually benifit from bow lift (our experience). Very nice!!

 

[dnyhuf]

Re: Prop question

Thanks Dhadley, I have learned alot, makes me want to learn more.

 

[Dhadley]

Re: Prop question

Your efficiency should go up too. There are props with more lift but those old Rakers are hard to beat sometimes. I think you nailed it!