Need help deciding upon a motor

Talk about anything that floats your boat (no pun intended). This is general talk about anything not related to boating/fishing.
The Hamilton Guy
Posts: 17
Joined: 05 Aug 2019, 11:36

Need help deciding upon a motor

Post by The Hamilton Guy » 05 Aug 2019, 11:41

Hey,
I have a wide body deep V Legend Boat with a 15 HP 4 stroke motor.
I need to replace the motor.

I am open to suggestions.

I am looking at buying a new 20 HP or 25 HP Mercury 4 stroke.
There is a cost AND weight difference between the two and I’m not sure if it’s significantly worth it to go up to the 25 HP motor.

Suggestions?


Sent from my iPhone using Tapatalk

lovedr79
Posts: 2566
Joined: 07 Mar 2011, 19:58
Location: Harrisonburg, Va.

Need help deciding upon a motor

Post by lovedr79 » 06 Aug 2019, 08:07

if you can afford it, go with the 25hp. i wish i would have when i bought my boat.
Grizzly 1448SC
Lowe 10' jon

User avatar
Jim
Site Admin
Posts: 17549
Joined: 29 Nov 2006, 21:00
Location: Shrewsbury, MA
Contact:

Need help deciding upon a motor

Post by Jim » 06 Aug 2019, 08:17

I have the same mentality, get the biggest one you can afford.

What is the weight difference?
Be Respectful!
This site is rated PG, No Politics, No Porn, No Bashing allowed!

The Hamilton Guy
Posts: 17
Joined: 05 Aug 2019, 11:36

Need help deciding upon a motor

Post by The Hamilton Guy » 06 Aug 2019, 08:38

60 lb weight diff between 20 and 25 hp


Sent from my iPhone using Tapatalk

User avatar
DaleH
Donor
Posts: 2381
Joined: 12 Dec 2014, 14:32
Location: Eastern Mass

Need help deciding upon a motor

Post by DaleH » 06 Aug 2019, 09:01

More HP will bring that hull alive! I’d go lightest 25hp you could get, with BEST dealer near you, if buying new.
#1) 1st tin rebuild, 18' Lund http://forum.tinboats.net/viewtopic.php?f=21&t=36583
#2) 25' Parker refurb from EMPTY hull http://www.classicparker.com/phpBB3/vie ... p?f=15&t=6
#3) 16' V-tin rebuild http://forum.tinboats.net/viewtopic.php?f=21&t=36465
#4 Procraft SV14
#5) 16' Starcraft entirely NEW Transom Skins http://forum.tinboats.net/viewtopic.php?f=3&t=37548

User avatar
onthewater102
Posts: 2148
Joined: 15 Mar 2014, 16:57
Location: CT

Need help deciding upon a motor

Post by onthewater102 » 06 Aug 2019, 09:28

Trying not to get too verby in the response, but you're comparing two totally different machines. This is not just a 5hp difference that mostly comes into play at the top end of the RPM range like I achieved by converting an older 2 stroke 20hp to a 25hp with a carb change. There are a number of other mechanical differences between the two setups beyond the additional weight that are far more important.

The 25hp is a 3 cylinder vs. the 20hp which is only a 2 cylinder. The 3 cyl will develop more low end torque out of the longer cylinders (same bore longer stroke - just like a 383 small block vs. a 350), but it also has a lower final drive ratio (1.92 vs. 2.15), so that torque will be put to good use throughout the operating range as it will be turning the prop faster at any given RPM speed on the engine. This should translate to both faster pickup and a higher top speed using the same pitched prop as you're generating more power throughout the RPM curve.

I've used the Yamaha F25 2 cylinder 4-stroke which has 2 larger cylinders (2.56" bore vs. the 2.40" used in either Merc) and a higher final drive ratio (2.00). It doesn't have sufficient low-end torque to get a boat on plane quickly even though it eventually will spin fast enough to develop enough power to achieve a respectable top speed (27mph in a decked 1448 with 2 guys & gear). Even though the F25 weighs about 15lbs less than the Merc looking at the spec differences I'd absolutely go with the 25 over either the Merc 20hp or the Yamaha F25.
I have a marriage license and a fishing license, but I only carry one in my wallet.


For Sale - Custom Hand Tied Jigs, Bladed Jigs,Custom Rods

2002 Alumacraft 1436LT w/ 1984 Mariner Tiller Converted to Remote & 55# Minn Kota Terrova 12v (removable)

1985 Bass Tracker III - Restoration w/ 1988 Mercury 60hp

User avatar
jethro
Donor
Posts: 1100
Joined: 25 Jul 2013, 16:12
Location: Henniker, NH

Need help deciding upon a motor

Post by jethro » 06 Aug 2019, 10:03

Agree on biggest you can afford. It will reduce the possibility of buyers remorse. The cost issue is basically buy once, cry once.
I fish, therefore, I am.

1993 Starcraft SF 14 DLX side console with 25 hp Mercury 2 stroke
2003 Sylvan 2100 Profish walkthrough with 150 Mercury Saltwater and 6hp Mecury 4 stroke kicker

The Hamilton Guy
Posts: 17
Joined: 05 Aug 2019, 11:36

Need help deciding upon a motor

Post by The Hamilton Guy » 06 Aug 2019, 10:40

Buy once cry once!! Like that.

I’ll go for the 25 HP.
There’s a Mercury dealer near me and a Honda one too. The Honda’s more money, but are the Mercury motors still good enough to not warrant the extra expense of the Honda?

Also...I’m going to opt for a tiller steer, manual start and tilt, as my boat is a 14’ deep V wide hull aluminum boat. I guess I have prop options to pick once I get into the 25 HP range? How do I decide what kind of prop I need?


Sent from my iPhone using Tapatalk

User avatar
DaleH
Donor
Posts: 2381
Joined: 12 Dec 2014, 14:32
Location: Eastern Mass

Need help deciding upon a motor

Post by DaleH » 06 Aug 2019, 11:53

Use the prop calculator listed as a ‘sticky’ in the Motors forum. It is dead nuts!
#1) 1st tin rebuild, 18' Lund http://forum.tinboats.net/viewtopic.php?f=21&t=36583
#2) 25' Parker refurb from EMPTY hull http://www.classicparker.com/phpBB3/vie ... p?f=15&t=6
#3) 16' V-tin rebuild http://forum.tinboats.net/viewtopic.php?f=21&t=36465
#4 Procraft SV14
#5) 16' Starcraft entirely NEW Transom Skins http://forum.tinboats.net/viewtopic.php?f=3&t=37548

The Hamilton Guy
Posts: 17
Joined: 05 Aug 2019, 11:36

Need help deciding upon a motor

Post by The Hamilton Guy » 07 Aug 2019, 09:44

I’m planning to get a new 25 HP 4 Stroke Mercury.
To save money I am planning to get the one with manual start and tilt.
Some people say that would be too hard to pull start.

Are the new 25 HP 4 Stroke Mercury outboards very hard to pull to start?


Sent from my iPhone using Tapatalk

User avatar
jethro
Donor
Posts: 1100
Joined: 25 Jul 2013, 16:12
Location: Henniker, NH

Need help deciding upon a motor

Post by jethro » 07 Aug 2019, 10:10

The Hamilton Guy wrote:
07 Aug 2019, 09:44
I’m planning to get a new 25 HP 4 Stroke Mercury.
To save money I am planning to get the one with manual start and tilt.
Some people say that would be too hard to pull start.

Are the new 25 HP 4 Stroke Mercury outboards very hard to pull to start?


Sent from my iPhone using Tapatalk
4 Strokes are definitely a little tougher to pull than an older 2 stroke with no mechanical valve train, but it shouldn't be that tough. I do think that for resale purposes e-start on a 25 horse is a really good choice. If you think you'll never need to resale the motor, or at least for a very, very long time, maybe it's not an issue, but almost everyone looking to buy a 25 horse outboard is going to want e-start. Don't forget that the e-start motor will come with a charging system to keep your battery topped up. I don't think the manual start will but maybe? A charging system is a big bonus for the house battery which runs lights, bilge, graph, etc.
I fish, therefore, I am.

1993 Starcraft SF 14 DLX side console with 25 hp Mercury 2 stroke
2003 Sylvan 2100 Profish walkthrough with 150 Mercury Saltwater and 6hp Mecury 4 stroke kicker

The Hamilton Guy
Posts: 17
Joined: 05 Aug 2019, 11:36

Need help deciding upon a motor

Post by The Hamilton Guy » 07 Aug 2019, 10:21

Ah! The charging system is a good idea. That way I don’t have to worry about keeping the battery charged.
Ok. Thanks.


Sent from my iPhone using Tapatalk

User avatar
onthewater102
Posts: 2148
Joined: 15 Mar 2014, 16:57
Location: CT

Need help deciding upon a motor

Post by onthewater102 » 07 Aug 2019, 11:08

No - you'll still have to charge it between trips, the gas motor doesn't run long enough to recharge the battery from the drain of graphs & lighting, even though in theory it could. The amount of gas you'd burn just to run your outboard as a generator long enough would not make sense. It's a nice feature that if your battery ever gets low you still have a way of powering your nav lights or bilge in order to get home safe.
I have a marriage license and a fishing license, but I only carry one in my wallet.


For Sale - Custom Hand Tied Jigs, Bladed Jigs,Custom Rods

2002 Alumacraft 1436LT w/ 1984 Mariner Tiller Converted to Remote & 55# Minn Kota Terrova 12v (removable)

1985 Bass Tracker III - Restoration w/ 1988 Mercury 60hp

The Hamilton Guy
Posts: 17
Joined: 05 Aug 2019, 11:36

Need help deciding upon a motor

Post by The Hamilton Guy » 07 Aug 2019, 11:42

As for the battery, the short shaft apparently can’t have the power tilt, but can have the power start. I learned it will still have a pull cord which is great if I need it.
Other than the power start and a fish finder, the battery really won’t be needed for anything else.

What type of battery would be best?

My boat has lights, bilge and a trolling motor but I never use them.


Sent from my iPhone using Tapatalk

The Hamilton Guy
Posts: 17
Joined: 05 Aug 2019, 11:36

Need help deciding upon a motor

Post by The Hamilton Guy » 08 Aug 2019, 14:50

I’ve been told that for my 14’ Legend Deep V boat the extra 60lbs of the 25 hp motor over a 20 hp motor, on the back of the boat, with the short shaft might be too heavy and let water over the transom. It was suggested I’d be better off to just get a 20 HP 4 stroke with electric start.

I’m thinking of going that route.

Which make of motor is better, a Honda or Mercury?


Sent from my iPhone using Tapatalk

Post Reply