I am current working on a new to me daily driver. Boat is an aluminum flatbottom pilothouse jonboat, 18', 54" bottom and 20" sides. I figure it weighs less than 1250lbs. I'm repowering it with a Mercruiser 140hp 3.0 and Alpha One drive. The drive has a Solas 14.3X23 aluminum prop. I'm sure this is way too much prop for this engine/ boat combo. Any ideas for a baseline would be appreciated.
Announcement
Collapse
No announcement yet.
Repower, need prop ideas
Collapse
X
-
All I see is a 130hp with a 1.94-2.0 gear ratio depending on the year model. In any case, a 23P is the recommended prop pitch for 800# load with 20 gal. fuel for a 2.0 GR. Should be ok for all GR. assuming your boat weight is indeed no more than 1250# for a total weight of 2800# with engine, fuel, and 800# load.
-
Hope to get it in the water in a few weeks, we'll see what it does then. I know the previous owner of the ski boat the power train came from said the prop was too much for it, but that was an '87 Avanti 170DL fiberglass boat. I'm not sure of the year model of the engine, he replaced it not long before finding the rotten transom. The stickers on the valve cover say 140, but he did say that cover was from the old engine and this one was a higher HP.
Thanks for the response, I'll update after the splash.
Comment
-
Its a 3.0, cant get much more HP that 140Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W
1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420
Past Boats
1970 Wooster Hellion - Merc 9.8
2002 SeaRay 190BR - 5.0 - A1G2 - "Cheeseheads in Paradise"
1984 Avanti 170DLI -3.0 stringer- "Ship Happens"
What’s behind you doesn’t matter. – Enzo Ferrari
Comment
-
I think the boat can handle the I/O easily. I was told that at one time it had a 115 outboard on it. The transom has been rebuilt with 1.5" of plywood sandwiched between 1/4" aluminum in and out. The front engine mount is tied into the transom and two stringers using 2X3" tubing, so I don't think there will be a problem there.
If other projects would stop getting in the way I'll get it in the water soon for a trial run.
Comment
-
I think you might be almost off to a good start. I’m aware of heavier 18 ft bowriders like bayliner 175 and maxum etc etc with the 3.0, 2-1 ratio and running well with a 23” not lightening quick out the hole but useable and fairly impressive too ends of mid 40’s gps. I think a 23” is a good start. I don’t think you would be more than an inch or two out on pitch, if at all.
Comment
-
What is the Gear Ratio of your Drive? Might as well get that info now. You should be able to find it on the trim or decal that wraps around the upper gear housing. As mentioned in the earlier posts, the 3 liter is pretty much maxed out already, and more recent MerCruisers had a 135hp rating.
A trial run with the 23" will give you an idea of where you are regarding propping. What year is the engine? That will come in handy determining the WOT rpm range it needs to be run, as thru the years the spec would change.
Comment
-
Mechmagcn I remember your earlier post regarding keeping this (under consideration at that time) Stern Drivel upgrade freeze safe during occasional cold snaps. Now it looks like you've committed. What is your plan?
....I'm still a bit envious of a Hub/Wife that can commute to work on the water.'96 Larson 174 SEI BR. 4.3LX 4 bbl Weber s/n 0F786604. Alpha One Gen II s/n 0F709315
Comment
-
Originally posted by Mechmagcn View PostStill not quite sure on the freeze protection. Our current boat has electric hookup for a small heater on a timer to keep my wife warm on our commute, I'll probably use either a block heater or magnetic oil pan heater.
although a help, I wouldn’t rely on this. A few years ago round here, about 50 or so engines were freeze damaged when the a breaker failed in the local marina. All the guys who had only used heaters and not drained their engines were caught out. Just a thought
Comment
-
iboats Boating Forum Directory
Over 100,000 Questions & Answers
-
-
Outboard Motor Topics
Mercury Outboards
Johnson Outboards
Evinrude Outboards
Force Outboards
Yamaha Outboards
Mariner Outboards
Suzuki Outboards
Honda Outboards
Chrysler Outboards
Tohatsu Outboards
Nissan Outboards
Outboard Motors: non-repair
Vintage Outboards
I/O and Inboard Topics MerCruiser
OMC I/O, Inboard
Volvo Penta
Propeller Help
Boat Propellers
-
Boat Repair and Products
Boat Building and Repair
Fiberglass Boat Repair
Marine Electronics
Boat Trailers and Towing
Boat Names
Boat Covers
Boat Parts
Boating Activities Talk
Boating Topics and Questions
Boating Activities and Destinations
Boating Blunders
Boat Shows
Wakeboarding
Water Skiing
Fishing Discussions
Freshwater Fishing
Saltwater Fishing
-
Boat Type Topics
Aluminum Boats
Bass Boats
Bowrider Boats
Center Console Boats
Cruiser Boats
Cuddy Cabin Boats
Deckboats
Fishing Boats
Fish and Ski Boats
Houseboats
Jet Boats
Jon Boats
Pontoon Boats
Powerboats
PWC Forum
Ski Boats
New Boats
Used Boats
Boat Manufacturers
Boats (250+ Manufacturers)
Bayliner Boats
Sea Ray Boats
Zodiac Boats
-
Comment