Newbie here! need help with prop/RPM/listing!!

[poolshark4016]

Howdy all!! What a great place for info, especially for a new boater. We just bought a new to us 1994 Four Winns 230 Horizon with a 454 OMC King Cobra 300 HP I/O. It cam with 3 props--two 19 pitch aluminum props and one 20 pitch stainless prop. As soon as we got it home, we took off the stainless and put on the aluminum as suggested by an avid boater.

We took her on her maiden voyage to a local lake on Saturday. With "correct" weight distribution on the boat, it seems to lists slightly to the left on plane. Sits true on idle. Also at 4600 RPM, we got to about 40 MPH. This seemed slow to us. The boat does not have trim tabs. I assume the speedo works properly but truly unsure. Manual says she should do roughly 49-50 WOT--certainly didn't feel that fast.

Question: Do we have the right prop?
Are there any quick fixes for the slight list?
Anything we can do to up the speed?

Thanks for ANY help. Also sorry if I missed any info or didn't specify correctly--I am really "green" to boating. Thanks SO much!

Steph:redface:

 

[QC]

Re: Newbie here! need help with prop/RPM/listing!!

Welcome aboard Poolshark! 1st thing I think you should do is borrow a GPS to verify speed . . . 4600 RPM, 1.42 gear ratio (strong belief), and a 19" pitch should be waaaay faster than 40 MPH. To go that slow you neeed to be at 30% slip which is very high for what is a reasonably high speed. I used 15% and got 49.5 which would be very respectable and doable if your numbers are right (pitch, gear ratio and RPM)

You kind of have three issues to deal with:

1) Prop choice which you should repost in the prop section when we figure out # 3 (why did someone recommend taking off the Stainless? )

2) List to port, this is normal as the propeller rotates to the right forcing the hull to the left. Try her with some weight to starboard. She will list at rest slightly to starboard, but may be flat at high speeds. This can be managed with helm adjustable trim tabs, but otherwise is common to single propeller boats. Sometimes this is difficult to check with your eyes from the helm. You can check with a level when she is on the trailer if you know all else is flat. Then recheck while underway and compare.

3) Not clear as to the performance of the engine itself. Really need to confirm all is running right to make any performance/propeller/speed optimization choices. She may be perfect, but you/we need to know that to make good choices. I think she is probably running right or you would not have got the 4600 RPM. I'd like to see numbers with the GPS and the SS 20". This also assumes the tach is right which is never a safe assumption . . .

Good luck!

 

[Bondo]

Re: Newbie here! need help with prop/RPM/listing!!

Also at 4600 RPM, we got to about 40 MPH.

Ayuh,..... Is that All she's Got,..?? Wide Open,..?? Balls to the Wall,..??

A BBC should spin a 19" prop to close to 5 Grand,... Or More....

My Guess is a down on Power, Sick motor....

 

[poolshark4016]

Re: Newbie here! need help with prop/RPM/listing!!

Thanks for the insight all. We will borrow brother's GPS and get a true reading on speed. Also we put on the SS 20" in place of the 19 so we may see better results from that as well. BTW, we were told to take the SS prop off until we got used to running the boat for safety reasons? I guess..lol.

More to follow after next outing (this weekend).

 

[QC]

Re: Newbie here! need help with prop/RPM/listing!!

If you're running in shallows it may be a good plan to run the Aluminum until you get more 'sperience . . . Nice lake that the bottom is obvious, run the SS.

 

[Don S]

Re: Newbie here! need help with prop/RPM/listing!!

4600 to 5000 rpm is the recommended rpm range for the OMC 454 HO engine. Which, BTW, is a 93, there was no 454HO in 94.

Did you have it trimmed out to best speed and rpm? Trim is not something you do by where the gauge says it is. You have it trimmed down to far and you will loose rpm and speed.

 

[poolshark4016]

Re: Newbie here! need help with prop/RPM/listing!!

4600 to 5000 rpm is the recommended rpm range for the OMC 454 HO engine. Which, BTW, is a 93, there was no 454HO in 94.

Did you have it trimmed out to best speed and rpm? Trim is not something you do by where the gauge says it is. You have it trimmed down to far and you will loose rpm and speed.

We are still working on how to trim to get the proper speed and so forth. Realized the year on the motor when I did some research on it. We are taking it out for a second time this weekend...when you talk about trimming, are you meaning to bring up the outboard just enough to where it is just under the water and not "tucked under" the boat? Still learning...thanks!

 

[Don S]

Re: Newbie here! need help with prop/RPM/listing!!

when you talk about trimming, are you meaning to bring up the outboard just enough to where it is just under the water and not "tucked under" the boat?

Yes, all the way down will help you get on plane, but you have to trim up (sometimes quite a bit) to get full rpm and speed.
When up on plane, trim up till your rpm starts going up and your speed starts dropping, That is when you are trimmed up too much.
Down too much is low rpm and speed.
Find the happy medium. Play with the trim, you will learn .

 

[poolshark4016]

Re: Newbie here! need help with prop/RPM/listing!!

Yes, all the way down will help you get on plane, but you have to trim up (sometimes quite a bit) to get full rpm and speed.
When up on plane, trim up till your rpm starts going up and your speed starts dropping, That is when you are trimmed up too much.
Down too much is low rpm and speed.
Find the happy medium. Play with the trim, you will learn .

Thanks so much, Don! We will give it a go this weekend and try to find that happy medium to get maximum speed. Appreciate the quick responses of this site.

 

[poolshark4016]

Re: Newbie here! need help with prop/RPM/listing!!

oops

 

[Don S]

Re: Newbie here! need help with prop/RPM/listing!!

Post that question over in Boat topics and questions (NOT engine), this forum is for IO problems, we also have a forum for Props. Have a look at the index of all the different specialized forums we have. http://forums.iboats.com/

 

[poolshark4016]

Re: Newbie here! need help with prop/RPM/listing!!

Post that question over in Boat topics and questions (NOT engine), this forum is for IO problems, we also have a forum for Props. Have a look at the index of all the different specialized forums we have. http://forums.iboats.com/

Ok Thanks !!