2000 VIP - Need Prop Change?

[KCobra78]

Purchased a 2000 VIP Deckliner 215 with a 4.3 Alpha One Stern Drive (2 Barrel - 190 HP) - 19" Pitch Prop (3 Blade - Alum) - The boat also has Smart Tabs on it. I had the lower foot rebuilt by the dealership when I purchased the boat. It would not run out of idle - so the 2 B - Carb was rebuilt as well. The boat has ran fine since then except for one time when it backfired and bogged down. I shut it off - checked the levels and it ran fine afterward for over 30 min back to the dock... Not sure what caused this but I could not duplicate it again.

My issue is my top RPM's are 3950 with a speed of 32 MPH as per the GPS. From everything I can find .. this engine should be 4400 to 4800 top RPM. I have used the Mercury Prop Online tool to Select the prop but it gives me 11 choices. If I am reading it right... it says best pitch would be 16.43.. I don't know enough to go forward. So any help would be great! I know my boat is pretty heavy...the program said Boat/Engine/Gear is 4900lb... so what diameter do I need as well ? Since the boat is heavy.... do I need a 17" with a larger diameter? Please help this rookie !

 

[KCobra78]

PS..... and do I need a 3 blade or 4 blade ? Cupped or Non-Cupped ? HELP ! LOL

 

[KCobra78]

• Boat type: Deckboat
• Usage: Overall good performance/0 ft
• Engine Manufacturer:
  Mercury
• Engine Type: Sterndrive
• Engine Year: 2000
• Number of Engines: One
• Engine Family: V6s
• Engine: 4.3LH
• Drive / Gear Case: Alpha 1.62 Gear Ratio

[h=3]DETAILS[/h]

• Calculated Pitch: 15.04
• Calculated Weight with engine(s):5,490.80 lbs
• Calculated Engine RPM: 4,600
• Calculated Boat Speed: 36.45

 

[KCobra78]

OK.... I found the weight of the boat (3200) and added 1200 in gear/pass with 44 gal of fuel on the prop selector... and got the results above..

It now has a lower pitch suggested...

Anyone good at this ?

Thanks

 

[steelespike]

Is 3950 @ 32 lightly loaded? We need the lightly loaded numbers to evaluate your setup.
Lightly loaded wot rpm and gps speed.If smart tabs are applied to aggressively they will slow the boat and may handle strangely.
I would suggest releasing the tabs all the way for the test.
All that figuring is ok but we need to know if the setup works as is with the light load. The boat and/or motor may have issues
A test run will tell us what we need.

 

[alldodge]

According to my findings is the dry weight of the boat is 2740 lbs. This link states they achieved 43mph with a light load.
http://features.boats.com/boat-content/2000/08/on-deck/

 

[KCobra78]

Steelespike - yes the 3950 @ 32 is with a light load ( Two Passengers) I backed the smart tabs off for the test - the boat actually gains .5 mph with them engaged.

-Break-

Thanks AllDodge for that additional information on weight !

 

[steelespike]

Boat dry weight is 2880 no need to add the motor.
My feeling is on a light load speed should be over 40.
AllDodge mentions 43 mph on a similar boat.
Is the bottom cleran and smooth
I do think your motor needs a check up.
A compression check,be sure the throttle opens all the way.
Timing set right and advancing as it should.
You need to make up about 800 rpm
Rule of thumb thats a 4" reduction in pitch.
I feel that a 17,19,or 21 would be more typical.
But as it stands a 15 is what you need.
I would wait till you check out the motor before a prop change.
Do you trim up for best speed?Does the boat respond to up trim?

 

[KCobra78]

Steelspike
Yes.. the bottom of the boat is clean and smooth... I just purchased it from a Dealership in Augusta, GA. They did a complete service on the boat and also rebuilt the lower end and carb. Would you still think I could have an issue with compression? I will check to make sure the linkage on the throttle goes all the
way open etc.. I would hope they would have noted any issues...but that could be my luck.... they did a river test with the carb rebuild as well....

I do trim up and the boat does respond.... I can hear the pitch of the engine change and the speed does increase a couple of MPH. It's not a drastic change..
but there is a change... The boat seems to get up on plane ok with the trim all the way down..... and once the boat nose is down .. trimming up does increase the RPM... not a lot like I said.. but there is a change..

I agree with you... from all I read about the boat prior to purchase.... the boat should run low 40's

anyone know the compression for a 4.3 V6 ? I can do that over the next few days and let ya'll know what's up from there..

Thanks again soooo much for everyone's input

 

[steelespike]

If a dealer is preping a boat for sale and does a water test they should note the results rpm and speed.
3950 and 32 mph clearly isn't normal for a 4.3.
When you pull the plugs for the compression note their condition and what cylinder.
Minumum pressure 100 psi and within 10% between cylinders.

 

[KCobra78]

Ok... I had a mechanic come by the house and check the compression.. All are within 5% of each other and avg 125 - He said all the plugs looked great and
the only thing he could find was a loose wire on the choke... so he put a new butt connector on it ...
He also checked the travel on the throttle and it is opening all the way..

What do ya'll think ? Change the prop?

It currently has a Mercury Black Max on it.. PN 832830A45 19P Which is a 14 1/2 x 19

Ideas?.... should I go to a 17 or a 15 ? Should I stay with the 14 1/2 or go up or down ?

Thanks in Advance for your Input

 

[steelespike]

Well the tech proved what wasn't wrong;he basically did what I suggested no effort outside of that.
I'm pretty sure there is a base line timing setting and while electronically advanced it wouldn't hurt to check the timing advance is accurate.
Are the plug wires original 15 years old? Did they change the outdrive gear ratio when they did the lower repair?
A 15" prop "SHOULD" get you into your rpm range. About 150 to 200 rpm per inch of change.
While the 15 will get you into the critical rpm range top speed could very likely be about the same or less.
But performance will be stronger.

 

[KCobra78]

Steelespike

Yes the wires are new. Both the plugs and wires were replaced by the dealership when they serviced the boat. I don't think they changed the drive gear ratio...
I will call them and ask though....

I am confused on the speed comment... are you saying that even though I change the pitch to at 15 and increase the rpms to normal range... I will still only
go about 32 MPH?

 

[steelespike]

Steelespike

Yes the wires are new. Both the plugs and wires were replaced by the dealership when they serviced the boat. I don't think they changed the drive gear ratio...
I will call them and ask though....

I am confused on the speed comment... are you saying that even though I change the pitch to at 15 and increase the rpms to normal range... I will still only
go about 32 MPH?

Your 19" prop theoretically moves 19" forward in one revolution. A 15" moves only 15" in one revolution.
Easier to turn so the motor can get within its operating range.
The 4.3 should be able to run about 4800 rpm with the 19" prop.
I did a quick calculation; Assuming 4800 with a 19 we get about 48 mph It's not unusual for a 4.3 to reach close to 50.
Your somewhat heavy deck boat may not get to 4800 its just a for instance calculation.But again should be well into the 40s.
4800 with a 15 gets 37 mph. So not the 32 I guessed but a significantly less speed. And actual numbers will depend on the actual rpm.
If you look up props for the 4.3 you'll note that a 15 is way down the list where your dealing with very hard to push hulls like a pontoon
The 19 is just about midway where you might find boats intended for a motor like a 4.3. And typical props would likely be 17,19 or 21.
Depending on typical load and activities.
Is your hull a deep V? 18-21 degrees at the transom?

 

[Tail_Gunner]

Now that's a pretty nice boat actually take no offense to this its a cool party barge not a performance hull. A 4.3 might be a tad small for that boat but that is a opinion. With that said my first order of business would be to install a 4 barrel carb.....Now to practical point a 16p 4 blade solas would probably win the day based off all the info given. Good luck it should be a great boat for gatherings and pleasant cruising. By the way the 4.3 is great motor but they dont have a lot of tourqe that 19 is pulling it down hard once you get a 15/16 it will be able to flex its muscle a bit.

 

[steelespike]

From his description I take it is a deck boat not a pontoon.
And we haven't expected 50 mph speed.There was some discussion of 4.3s flirting with 50 mph.
He describes backing off the smart tabs for the test run.
He talks of the boat responding to up trim few pontoons
have much use for trim.There is some mention of a similar model making 43 mph.

 

[Tail_Gunner]

From his description I take it is a deck boat not a pontoon.
And we haven't expected 50 mph speed.There was some discussion of 4.3s flirting with 50 mph.
He describes backing off the smart tabs for the test run.
He talks of the boat responding to up trim few pontoons
have much use for trim.There is some mention of a similar model making 43 mph.

Party barge used a term of endearment, a good friend has one in a starcraft damm nice boat's for a social gathering or family affair.Yes the 16 should take it to the mid fourty's with that type of hull the more blades in the water the better