08 60hp merc efi 4 stroke planing

[shimano19]

I have a 2008 merc 60hp efi 4 stroke and sometimes I have an issue getting it to plane With 3 people in the boat. It's on a 16' smokercraft pro angler XL rated for max 75hp. I have the motor trimmed all the way down, and at WOT it will sit at 4000rpm no matter how much I trim up, eventually after about a half km the rpms will increase, get on plane and will hit 6000rpm. I have switched the factory prop from a 13 pitch to a 12 pitch and have a hydrofoil on the outboard. The motor runs very smooth and always starts first shot. Could there be any issues with it or is this just how it is with 3 guys?

Thanks

Edited June 2, 2016 by MikeCmuskie

[Dara]

I would say thats just how it is. My 60 yamaha is the same way especially loaded and into the wind.

Them 4 strokes just don't have the hole shot snap of a 2 stroke

[NANUK]

Hard to tell without size of boat, size of outboard and maximum hp rating for that boat.

I run a 4 stroke on my boat and it gets on plane before you can count to 3, that's with the kicker hanging on the transome.

I have it maxed out HP for the boat.

Edited June 2, 2016 by stonefish

[Sinker]

Hard to tell without size of boat, size of outboard and maximum hp rating for that boat.

Yes, this.

 

S.

[shimano19]

it's a 16' smokercraft pro angler xl with 60hp 4 stroke merc efi

Edited June 2, 2016 by MikeCmuskie

[shimano19]

Hard to tell without size of boat, size of outboard and maximum hp rating for that boat.

I run a 4 stroke on my boat and it gets on plane before you can count to 3, that's with the kicker hanging on the transome.

I have it maxed out HP for the boat.

Haha sorry was typing in a rush at work, I'll edit it

[DanD]

Is the motor mounted at the proper height?

With the motor trimed parallel to the keel, the bottom of the cavitation plate should be in-line with the keel. If the plate is to low, it can cause gear case drag and make it harder to get on plane and you'll loose some top end. If to high it can cause cavation and again make it harder to get on plane or the prop will just spin out.

I been tolled no more then 3/4" either above or below the keel.

With you saying that the rpm stay low for a long time; I'm thinking the motor might be to low?

 

Dan.

[shimano19]

Is the motor mounted at the proper height?

With the motor trimed parallel to the keel, the bottom of the cavitation plate should be in-line with the keel. If the plate is to low, it can cause gear case drag and make it harder to get on plane and you'll loose some top end. If to high it can cause cavation and again make it harder to get on plane or the prop will just spin out.

I been tolled no more then 3/4" either above or below the keel.

With you saying that the rpm stay low for a long time; I'm thinking the motor might be to low?

 

Dan.

Will check that as soon as I'm home

[NANUK]

What is max HP rating for your boat ?

What is prop size ? Dia & pitch ?

[shimano19]

What is max HP rating for your boat ?

What is prop size ? Dia & pitch ?

Max 75

Prop is 11 3/4 diameter pitch is 12

[DRIFTER_016]

First a question: what do your RPM's max out at while running?

You need to prop so you get close to max RPM to be running most efficiently.

As stated check your motor height. Generally you want the cav plate to be level to 1" below the bottom of the boat.

 

I have a couple of suggestions for after you check out motor height and WOT RPM.

 

1/ ditch the hydrofoil and replace with a pair of Smart Tabs.

2/Change out your 3 blade prop for a 4 blade.

[lifeisfun]

I'll second the suggestion DRIFTER_016 gave you on smart tabs, have them and love them. http://www.nauticusinc.com/smart_tabsSX_automatic_trim_tabs.htm

Make sure first that your motor is properly mounted as suggested by others above.

Edited June 2, 2016 by Lifeisfun

[Sinker]

I have a 16ft starcraft with a 40 horse tiller. It will jump on plane in seconds.

 

Something seems off with your settings on the engine.

 

Check the height for sure, and also check where it sits when trimmed all the way down. It seems like its sitting too high.

 

Trim up=bow up

 

Trim down=bow down

 

S.

[AKRISONER]

a close friend has a 16 foot smoker craft with the four stroke merc and the thing wont plane with one person in the boat...

 

once it does get on plane it bounces around and feels like you are getting in a car wreck every time it hits a ripple...not a fan at all.

Edited June 2, 2016 by AKRISONER

[Dara]

Just about exactly what I have only in a Sylvan and also rated for 75

 

Mostly it does ok but when things aren;t right it just hates to get on plane

tops out with just me at 35 mph on gps

5000 rpm gives it 30 mph with 2 people

Edited June 2, 2016 by Dara

[shimano19]

WOT is 6000 while on plane, when it's trying to get on plane with 3 people it will sit at 4000rpm and will randomly start climbing and hit 6000rpm. Boat planes quick and fine with 2 people. Cav plate sits level to bottom of boat. I've read of a lot of people having this issue. I think it's just a weight issue since it's good with 2 people. Was just wondering on everyone's insight

[DRIFTER_016]

By putting a set of smart tabs on it you will be able to get the back end to lift faster and hopefully pop up on plane faster.

A 4 blade prop will also help getting out of the hole and up on plane more quickly.

It does sound like your boat is pretty maxed out weight wise with 3 in the boat.

[Mister G]

You might already be getting all you can out of a 4 stroke Merc..........it's not a 2 stroker and never will be......it is what it is.........

 

Last resort, get a E-TEC and watch the huge difference in the hole shot.......

[mike rousseau]

I don't know that boat but I'll guess its a console

 

I've seen 16' consoles having issues with 3 guys and gear

 

Fairly normal

 

We used to get the biggest guy to go to the front of the boat to help it plane out

[BillM]

I have a 16ft starcraft with a 40 horse tiller. It will jump on plane in seconds.

 

 

 

Loaded up with 3 guys and gear? I think when the OP is by himself the boat is fine. It's only when it's loaded that it's a problem.

[Fisherman]

Fill two big coolers and put them in the front, just for curiosity. I have to do that with mine if it's rough out.

[Sinker]

 

Loaded up with 3 guys and gear? I think when the OP is by himself the boat is fine. It's only when it's loaded that it's a problem.

3 guys, gear, and 8 dozen duck decoys i still get up on plane and run 22-23mph.

 

 

3 guys and fishing gear is no problem at all, even in rough water.

 

S.

[Dutch01]

I have a 16' Legend SC with a 40 Merc 2 stroke. Less power than yours, but two stroke, and probably similar hull to yours as I think Smokercraft made Legend at that time (if not still).

 

Trimmed down, my boat won't plane out with 3 in it. When I feel it stall out a but I trim up a little at a time and she gets fully planed. Eventually.

 

My top speed is about 31-32 mph with 3 guys.

 

I'm guessing that you're just maxed out with 3 guys in the boat as it's currently setup.

 

If you get the trim tabs please let me know how they work. Maybe they'll work for me too.

Edited June 3, 2016 by Dutch01

[scugpg]

What's the hull weight and do you have any batteries up front? does the boat sit quite high in front when it's trying to plane?

 

Appears the new 16 xl's now have a 90hp max.

Edited June 3, 2016 by Spooled

[AKRISONER]

hearing this stuff is concerning.

 

I run a 14 foot tinner with an 91 suzuki 15, loaded literally to capacity (casting deck, gear and people) and i still run 21mph.