Slow plane when loaded heavy.

[johnsobo]

15 Z6 115 4 stroke command thrust (2.38:1 gear ratio) 25 pitch fury prop no plugs, 3 batteries noco 3 bank charger. I usually fish alone and do not use the live wells so it perform quite well and planes quickly and around 50/53 top speed

Lately I have had a fishing partner, with 2 guys, tourny load, full live wells, only 1/4 tank of fuel it is kinda slow to plane with the nose high. It runs fine, vessel view had me bouncing between 6050 and 6100 rpm (max rpm 6000) at 48 mph so I know the prop is correct. Guessing I need a foil because if I drop to a 24p fury I will over rev.

Thoughts?? Thanks

[John Jackson]

Yes, a foil will help. So will a 25" or 26" Bravo. Nothing holeshots better than a Bravo.

[jarhead175]

When the nose is up is the motor screaming or bogged down? Ever notice rpms when it breaks over?

[johnsobo]

When the nose is up is the motor screaming or bogged down? Ever notice rpms when it breaks over?

I would say bogged down, kinda chugs along then breaks over . Sorry for the edit I remember looking at the tach but cannot remember the rpm.

[Fatshaft Merc]

Open up a vent hole.

[jarhead175]

Agree sounds like it needs more venting. Next question do you know your prop to pad?

Always set up a boat to run with a tournament load (full of fuel, livewells full, two adults, and their gear). Get it to run loaded and it will only be better light set it light and load it up you will be unhappy.

[lpugh]

What is the RPM when the bow lifts to get on plane, should be around 3500
As others have mentioned it may need more venting
I am suspicious the motor is to high and prop it to big as you have 21 percent slip which would cause a poor hole shot and excessive slip if to high
A 24 Fury at 15 percent would give you about 5800 and 49 MPH as well as improves hole shot. Start off with the p to p set at 4 in and then adjust the height to obtain the highest GPS speed to find the sweet spot. Use a prop calculator to obtain the slip numbers for you boat
Fury like to be run deeper and usually no plugs in them
Try dropping your motor a inch with the 25 and check the slip numbers, the RPM may drop a lot with very little or no speed loss
You must get the prop slip down first to evaluate what you need

[mdtritn21]

A 25" prop is too much pitch for a 115 on your boat and your running it high and slipping real bad to get it to turn those rpm's. I'd try to find a 23" tempest or a 23" fury to test. It should give you the same top speed but a lot better hole shot. Do you have a jack plate on your boat now?

[John Jackson]

Keep in mind his 2.38 gear ratio. Running a 25" prop is like running a 20" prop with the normal 1.75 ratio.

[johnsobo]

Thanks for the help all. If it does not rain sat I will fill the boat up and take my buddy out to get the numbers requested as well as p2p. Once I get all the info I will post with all the info. For now the prop has no plugs and no jack plate.

The motor is mounted all the way up on the transom, Should I Invest in a small jack plate or just pay to have the motor dropped?
Thanks John

[jarhead175]

Jackplate

[lpugh]

^^^^^^^ yep

[johnsobo]

One thing I was able to check since it was easy and the boat is in my driveway was prop to pad. It appears I have 5 in.

[lpugh]

Have you verified the tach is accurate, if analog it may be way off

[johnsobo]

I got the info from my vessel view mobile (smartcraft).

[jarhead175]

5" sounds too deep. Most boats I have set up I start at 3-1/2" and go up 1/4" every run till I lose speed or water pressure then drop it back down to the previous setting and leave it. Once you find that sweet spot for your hull and they are all different even if it is the same exact model then you fine tune the prop to get the rpms you want.

[mdtritn21]

Do you have a jack plate or is the motor bolted to the transom? 5" prop to pad sounds like it's mounted in the top hole on the motor without a plate. If it is try raising it one hole to 4.25 under and that is where it should run. That may help but I still say it's too much pitch for that boat and motor with a load. Mercury makes a 2.07 lower and a thrust command lower with 2.38 gears which it what you say you have on their 115 hp motors and none have 1.75 gears.

[johnsobo]

So I got the boat out Saturday, I will start with some of the stats that were requested
2015 - 115 Merc 2.38 lower gears
25p fury that was worked on once before no plugs
No jack plate
3 batteries
Noco 3 bank charger
Motor mounted as high as it will go
P2P 5in
2 guys 450 lbs estimate
32 gallon live well full
1/2 tank gas 12 gallons?
From stop give full throttle nose goes right up. Rpms rise to 3000 but seems like 3000 to 3500 takes a while. At 3500 nose starts to come down. By 3800 rpm boat is on plane...
keep going but added weight of gas dropped the speed again...this time down to 46.
Rpms still 6000

Called Mark Croxton we spoke for awhile and he thinks that last place that worked on my prop messed it up since it never seemed right since I got it back and the slip is so high.

He also suggested dropping to a 24 fury. I ordered one but the weather looks like crap for a good while.

I will update what happens with new prop..

[lpugh]

The 24 will help a great deal, I assume a Fury. If so after getting good baseline info talk to Mark about tuning it for your boat, I am sure you are on the right track now. I would also ask Mark as to what prop he thinks would be best for you
I would also consider installing a Manuel jack plate as that will make tuning a lot easier and save some setup time

[jarhead175]

As high on boat as possible and still 5" p2p? Is it a long shaft motor?