www.iFourWinns.com

Dedicated to Current and Future Owners
It is currently Thu Mar 28, 2024 11:07 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 8 posts ] 
Author Message
PostPosted: Wed Oct 30, 2019 9:58 am 
Offline
Guppy

Joined: Wed Oct 09, 2019 9:48 am
Posts: 5
Hello,
I'm replacing the prop on my 2004 194 funship.
I'm running a newer Volvo penta 5.7l / sx outdrive. Upgraded from the 5.0gl by previous owner.

I'm not very familiar with props other than I've been running a 3 blade aluminum. Not really sure on the specifics of pitch and diameter other than it's whit'my last mechanic told me to get. So I'm guessing OEM. 

I'm thinking about swapping with a 4 blade stainless steel prop but have no clue what specs to get.

Been thinking something's been off with this current set up as I've never been able to break 40mph full throttle and it takes forever to plane with more than 3 ppl onboard.

I usually cruise at around 3500rpms at about 20-25mph
and at about 30-35mph at 4500-5000rpms.

I'm thinking a good bit of this has to do with a wrong prop for what im running.

pulling the boat out to swap the prop in the next week and fix an oil leak in the outdrive I noticed on my last outing. Hopefully a simple fix. (Stupid logs)

Any help or input you guys could give me in this matter would be greatly appreciated!







UPDATE:

Ok so I resealed the outdrive and changed the gear oil.
I've also scrubbed the hull and upgraded to a new 4 blade prop.

Got her back in the water today n noticed a few things

1. Hops up on plane and accelerates a hell of alot faster! So I'm super happy about that.

At WOT I'm clocking 39mph on GPS at 5000 rpms.

Cruising at 30mph around 3500rpms.

Numbers still seem a little off to me tho. Specs on this boat with the smaller 5.0l engine suggest top speed of 50mph WOT at 5500rpms.

Keep in mind I'm running a 5.7l vp engine.

I understand with 4blades I'll sacrifice top speed but shouldnt I still be around 45mph or hit 5500rpms still?


Top
 Profile  
 
PostPosted: Wed Oct 30, 2019 10:39 am 
Offline
Guppy

Joined: Wed Oct 09, 2019 9:48 am
Posts: 5
Prop I'm running now is a 15x15 turning point 4 blade


Top
 Profile  
 
PostPosted: Wed Oct 30, 2019 4:40 pm 
Offline
email admin your custom rank

Joined: Thu Jun 29, 2006 10:26 pm
Posts: 5661
Location: Long Island NY
It could be that while the engine was upgraded, the outdrive has the same gear ratio as the less powerful 5.0 engine. So that is the limiting factor, the 5.7 can pull a taller gear ratio due to more torque but you are still rev limited to not more than 5,000 max wide open rpm. You may have it set up as well as it can be.
I'm using a 15.5x15 on my OMC Cobra with the smaller 4.3 V6. More or less the same performance, tops out at just about 5,000 rpm.
These old school pushrod engines are not intended for over 5000 rpm operation unless the valve train is upgraded. You can try going up in pitch, that might give you a few more mph but your acceleration on plane will be slower.
Also, make sure to use the right viscosity oil for marine engines, auto engine viscosities can break down with sustained high rpm use such as in boats. I use Merc's 25/40 which holds its viscosity well and is easy to find. Volvo used to recommend a full syn 30 wt and then changed to a 10/40 full syn.

_________________
88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II


Top
 Profile  
 
PostPosted: Wed Oct 30, 2019 5:20 pm 
Offline
Guppy

Joined: Wed Oct 09, 2019 9:48 am
Posts: 5
Thanks for the response.

That makes alot of sense. How do I upgrade the gear ratio if possible?

Either way, with the 5.0l engine this boat is supposed to get closer to 50mph wot at 4600 rpms.


I do enjoy the speed at which this prop pops me up on plane. But i would like to be able to top out at a higher speed so I can cruise at a lower rpm for economy sake.

I typically ride with anywhere from 3-9 adults n tow tubes alot.. old prop took forever to get on plant with a full boat. N I had to Jimmy the boat to even make that work.. hoping 4 blades improved this.

I'm told the new prop is more than likely under pitched as my rpms are topping out at 5000 rather than 4600


Top
 Profile  
 
PostPosted: Wed Oct 30, 2019 5:31 pm 
Offline
email admin your custom rank

Joined: Thu Jun 29, 2006 10:26 pm
Posts: 5661
Location: Long Island NY
It’s expensive! You have to change the upper gear housing, not worth it IMO.
If you go up 2” in pitch you should be back down at 4600 and might pick up a few mph. Each 1” in prop pitch is about 200 rpm. So a 3 blade 15x17 would probably put you right there.
If you are going to use the boat for water sports though I'd stay closer to 5000, because the load of pulling up people is pretty substantial. Being slightly under-propped (as long as not over 5000) is much better than over propped. Over propping strains the engine every time you pull it up on plane and that will eventually overheat exhaust valves and lead to rough running, and the need for a top end overhaul.

_________________
88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II


Top
 Profile  
 
PostPosted: Wed Oct 30, 2019 7:36 pm 
Offline
Guppy

Joined: Wed Oct 09, 2019 9:48 am
Posts: 5
Question.

The high rpms. I've noticed when I hit sharp turns while towing tubes or hitting big waves the engine revs and i loose thrust. Could this be the rev limiter kicking in?

I have to quick shift to neutral and back in gear to reenguage.

Could this be a combo of being underpropped and cavitation?


Top
 Profile  
 
PostPosted: Wed Oct 30, 2019 7:39 pm 
Offline
Guppy

Joined: Wed Oct 09, 2019 9:48 am
Posts: 5
And as far as adjusting pitch, I currently run 15x15 4 blade.

My old prop was 14.5x19 and still never saw over 40mph even being over revved at 5000rpm.

Think I wanna stick with 4blade and adjust pitch. 19 or 21 pitch has been suggested your thoughts?


Top
 Profile  
 
PostPosted: Fri Nov 01, 2019 11:11 am 
Offline
Shark

Joined: Tue May 06, 2014 7:25 am
Posts: 145
Location: Ohio
jay1686 wrote:
Question.

The high rpms. I've noticed when I hit sharp turns while towing tubes or hitting big waves the engine revs and i loose thrust. Could this be the rev limiter kicking in?

I have to quick shift to neutral and back in gear to reenguage.

Could this be a combo of being underpropped and cavitation?



That sounds like cavitation from underpropped. Switch to a 17 pitch 4 blade and I believe turning point does an exchange program if your prop isn't damaged. I run a 15x17 4 blade SS Powertech on our 5.0 gxi H200 which will still do over 50mph.

_________________
2008 H200 Frenzy Edition 5.0 GXi

1993 Horizon 190 5.0 EFI (Sold)


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group