Prop help. 194 funship

[Jay1686]

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!

 

[QBhoy]

Hi
You really need to know what prop is on it now and what rpm you are getting flat out and trimmed up.

Its very strange what you are getting now.
That boat should likely get a fair bit more speed than that. At first one might presume you are over propped if it’s slow to plane and struggling top end...but when you say it’s doing 3500 rpm at only 24 mph...that would suggest you are under propped to me.
Is the boat about 19ft ? I’m not familiar with the boat really.
I have a similar sized boat with only a little more power at mayne 40hp or so more. It will sit at about the same speed at 2200/2300 rpm.

 

[Jay1686]

It is a 19 footer.

I'm pulling it out Monday, scrubbing the hull, pinpointing to oil leak and pulling the prop..

I probably am over propped.

The manual says it should hit 50mph wide open with the original 5.0l vp engine at 5000rpm with OEM prop 14.25x21, 3 blade alum so I know theres something wrong.

 

[Jay1686]

Since I've got the 5.7l engine in her, would that affect the size of the prop I use?

I do want to move back to stainless steel and switch to 4 blade.

 

[QBhoy]

Yeah it would defo affect the prop you need usually. Are you sure the original 5.0 was a GL ? I think they are carb engines and usually 4800 max.
Anyway. I’m not sure what you are, over or under propped. If you were over propped I don’t think your rpm should be as high as that at 24/25 mph. I would have thought it would be at least a 50 mph boat and more with the 5.7.
Mine is around the 300hp mark or mayne slightly more. She will run over 60 gps any day of the week and has seen just on 67 mph gps with one prop on it. Likely a more specialised hull, but I’m sure it will be every bit as heavy at 1400 kgs.
Hows the compression ? And all the basics

 

[Jay1686]

Honestly not 100% I know it was a 5.0 cause he kept the plastic cover plate. Could a been a girl. But now it's a 5.7 but not sure of the lettering.

I'll let u know the prop when I pull it off Monday.

Not sure how to test compression. Was told it was fine last mechanic that I overpaid lol

 

[Bikestdy]

How are you reading speed? If you are going by speedometer, could you please recheck with GPS? You also say that you plan on scrubbing the hull. How bad is it, does it have a lot of growth/buildup, that also can affect performance.

 

[Jay1686]

Update. Pulled the prop today. And pinpointed my oil leak.
prop shaft seal so easy fix.

The prop I had was a 14.5x19 3 blade


I read GPS speed. Never been over 40 mph

 

[Jay1686]

Ok used prop wizard n ordered a 4blade 15x15 turning point prop and the necessary seals.

Will keep you updated once I have the boat back in the water with how it affects my performance

 

[QBhoy]

Ok used prop wizard n ordered a 4blade 15x15 turning point prop and the necessary seals.

Will keep you updated once I have the boat back in the water with how it affects my performance

Hi

with respect. How did you determine that ?
Its miles off the mark for sure, given your figures.
Honestly miles.
If you get 35 mph at 4500-5000 rpm with a 19” and it’s seen 40... no way you need a 15”. Honestly. Don’t order that prop.
Go get some exact GPs and rpm figures.
What did you put into the calculator

 

[briangcc]

Yeah I agree with Qbhoy here. I know nothing about props but I can tell you that on my 19' Four Winns with the 270HP Volvo I was swinging a 3 blade 19 prop and pulling 50-55 GPS. Something's off if you're using more motor and a similar prop.

Shoot...my lowly 180HP 4.3L swings a 4 blade (I think its 19 or 21 pitched) and will do 50 GPS. And that's a lot less motor than you're packing.


I'd check the tach first to see if its accurate as a 15 pitch prop seems awfully small. I wouldn't order that and would start elsewhere like...are you sure you're getting full throttle? Engine health? Don't rely on hearsay from previous owner, actually dig in and confirm what you were told.

 

[Jay1686]

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?

 

[Scott Danforth]

if you bought the 15 pitch prop, you bought the wrong prop as others indicated.

we are here to help, however with a 5.7, you should be about a 19 or 21 pitch prop. however to determine what you need, you first have to go thru all 6 questions needed to determine the correct prop.

see the stickies.

 

[Jay1686]

What 6 questions?

The prop the turning point wizard gave me was a 15x15 4 blade prop

 

[Jay1686]

It does perform better but not optimum with this prop.

I do like turning point for sure.

What do I need to find the right size?

Engine is in pretty good health. At least I feel I maintain it well.
Still it is my first boat. How do I make sure I'm getting true full throttle?

 

[Jay1686]

Also trying to figure out the exact model of my engine.
I think it's a 5.7gl but I'm not really sure. The old one was definitely the 5.0gl

Any ideas?

 

[Scott Danforth]

what does the serial number tag on the side of the block say it is? you posted a picture of the intake manifold

 

[Jay1686]

Unfortunately I cant seem to find one.

 

[Jay1686]

Correction. Seems I wasnt looking in the right place. Tho I have no idea how I'm gonna be able to get to it but I'm bout to try

 

[Jay1686]

Nope no tag.