WOT of 5100. Manu. says 4400-4800 What to do?

[darrklim2]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

OH PS the drive ratio is 1:81QUOTE]

Sorry but I don't think this is possible. You probably have a 1:1.81 not 1:81.
Meaning 1 revolution to 1.81 revolution

 

[John_S]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

"I figure thats AWESOME since the prop will spinn 81 X to one crank shaft turn. Sounds pretty fast to me. Maby thats too fast for a 23p?"

Actually, it means it takes 1.81 engine revolutions for one revolution of the prop. The "normal" V6 regular altitude ratio is 1.62, where it takes 1.62 crankshaft revolutions for 1 turn of the prop. I'd have to check a prop calc, but the 23" pitch w/1.81 is about the same as a 21" w/1.62 ratio.

It is easy to tell if hub is spinning, just mark the hub and prop. Do a run and recheck the marks. If they moved. hub is slipping.

A larger diameter prop will give more bite on accel, but a runabout won't benefit as much as a cruiser. On a runabout the larger diameter will lower your top speed some.

The best trim position depends on hull, weight, motor, prop, etc. I trim all the way in, and then bring out to the first mark on trim gauge. It is about 1/4 of the way up of the available trim.

 

[BAYLINER185]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

YEA I trim pretty much exactly like that myself.

So I may wind up with better performance then with the 21P? Im really confused on all this now up in pitch or down I have no idea. I need to go down and see what the out come is to know weather to go up or down to get this thing up in MPH.

I will check for a spinning hub this week end, That is definetly possible. I know about the markign technic to check and I figured I may wind up doing it to see what happens.

Thanks

Vic

 

[John_S]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

The 21" will give you a better hole shot. Less top speed. If your hub is spinning, you don't have a good baseline. With your ratio, I suspect you will end up back with a 23".

 

[MikDee]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

Just a note here, a bigger diameter prop is usually not needed on an average small, fairly light boat. I had a 24' SeaRay Cuddy with a 260 Mercruiser that used to fall off plane when turning, so I had to go to a larger diameter prop of the same pitch 17", and it did the trick! If I remember correctly, I went from a Mercruiser prop, to a Michigan prop, to get the larger Diam. & same pitch. Don't go with a larger Diam. prop then you need, or it will scrub speed.

 

[BAYLINER185]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

Well Since the new prop wont show up till MONDAY I plan on breakign off from work as early as possible to marrow afternoon and head out to the lake and do a hub slip test. If it is slipping then GREAT I think thats an easy fix. When the new prop coems in Ill go out and give it a try and see what it really does. Not much I can really do right now.

I wounder if I can tell by pullign my prop and re mounting it? I never had a problem in the past with hub slip but I wasn the one who mounted this prop so I supopose anything is possible.

Thanks for the advise, Ill check into it all as the prop will arive next week but at least for now I can try a few things until it comes.

Vic

 

[BAYLINER185]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

Well aparantly the tach wasnt set right by the factory!

Sine my BAYLINER dealer reset my tach and I just got back from the lake I am very happy to report a top speed of 52 MPH on the stock 23pitch prop.

So now what do I do when the 21P I ordered arives?

I guess I can save it as spare just in case or I can send it back to IBOATS.

Top RPM was just about at 4800 RPM and the boat can problably go faster right around 5K but Im still in break in and I dont wanna push it over the limit just so soon.

BAYLINER 185 is impressivly fast!

iM SO HAPPY NOW!

 

[doublehelix]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

Well, after reading all the replies here and over on the Bayliner site, I stayed with the 21" pitch, went to 4 blades, and decreased the diameter by 0.25". Stuck with Aluminum just cause its inexpensive and I tend to find all the stumps no one else does. Tomorrow is test day.

So here is my setup:
3.0L I-4 Mercruiser in a 18.5' year 200 Bayliner - Capri 1950.
14" x 21 pitch 4 bladed aluminum prop
Sting Ray XPII Hydrofoil Stabilizer

 

[Crownie2]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

Let's get back to the basics...

According to the Mercury Marine Prop Calculator, unless you are at high altitude, for that gear ratio, you are propped correctly and should expect about 43mph at 4,600 rpm's (unless their other issues with your boat we don't know about).

Sounds reasonable to me. Better get the tach checked.

Also, I don't know about Bayliner, but normally the drive is shipped without the prop and the dealer installs the prop he wants.

If the tach proves to be wrong, I would recommend a 3 blade SS prop for overall best performance.

Bob

 

[StangLX302]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

Well, after reading all the replies here and over on the Bayliner site, I stayed with the 21" pitch, went to 4 blades, and decreased the diameter by 0.25". Stuck with Aluminum just cause its inexpensive and I tend to find all the stumps no one else does. Tomorrow is test day.

So here is my setup:
3.0L I-4 Mercruiser in a 18.5' year 200 Bayliner - Capri 1950.
14" x 21 pitch 4 bladed aluminum prop
Sting Ray XPII Hydrofoil Stabilizer

How'd it work out?

 

[U Rest U Rust]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

I had the exact problem. 89 sea sprite 23' w/cuddy (heavy). 5.0 merc i/o. had a 15X17 took a long time to plane out and lost plane on turns and at 20mph. tough handling as well. At WOT 35 MPH at 4100. Went to a 16 x 20 and it planes out alot quicker and handles better. I have not WOT. will try it today and see where I am at. Would like to get htis puppy to low 40's at 4400-4600 but I dont think thats going to happen....

 

[doublehelix]

Re: WOT of 5100. Manu. says 4400-4800 What to do?

Well I tried the 4 bladed Solas Aluminum prop in 21" pitch and 14" diameter and something was seriously wrong!! The hole shot seemed slugish like the boat was stuggling to turn the prop. The max RPM went down to something like 4100. I could not believe that the RPMs would suffer so much by just adding a blade and changing the diameter DOWN by 0.25". I did like the prop for just one reason. It got the boat on plane about 200 RPM lower than before. But everything else sucked. Are the Solas Props Cupped? That is the only explanation that I could come up with. Perhaps when you add a blade, you need to go down in pitch? But remember that the title of my original post was that I was overreving so I thought, stay with the same pitch, and by increasing the blade count that would lower my RPM and everything would be OK. Wrong!! I sold the Solas Prop on Ebay since iBoats has a "no prop return" policy. That sucks.

I have a Mercury Black Max prop on order in 14.25 x 21 pitch and will try that. I is just a replacement for what I now have (minus the dings and missing chunks) so it should perform as well and maybe better that what I had originally.