I have a 2150 LSC with the Mercruiser 5.0L MPI and 21 Alum Prop. With a very heavy load (4 adults, 4 Children, all our stuff and Fuel) it was tough to get on plane. We did enjoy rushing everybody to the front of the boat during the hole shot but I am looking for a better solution. My first inclination is to go to a smaller bite prop like a 19 and/or trim tabs. For the technically minded, the 21 Alum prop is the recommended, I get WOT of 4800 RPM at 50 mph (GPS) so the prop seems fine but want to be able to take another family with me and tube and such. Thanks in advance for your help. PS. I also posted a similar question under another thread with no response.
Prop Engine Combinations 2150 LSC
- Thread starter enod
- Start date
For heavy loads and the ultimate water sports prop the Mercury High-5 is the way to go. I would find a dealer with a demo program and borrow a 19 pitch. I think you would be amazed at what it does for your hole shot and pulling power.
Thanks for the input. I figure worst case I can try a 19 and switch props as needed depending on my use for the day. Not too hard to do and with just the four of us the 21 works great. I want to try a trip from Lake St. Clair down the Detroit river and out into Erie to Put-in-bay and the 21 will be nice. Any other advice from others?
WRONG.
The 5.0 will not handle a 21" Prop on anything short of a piece of plywood. Fully load the boat...fuel, water, beer, beer and people. Load it to the max weight permissible by your USCG Placard.
Bring her to WOT. Record the RPM and speed. I'm willing to bet the RPM is not close to the manufacturers specs. Keep the diameter as large as possible. Drop the pitch ~1" for every [EDIT] inch 100 RPM's shy you are of max RPM. Start your prop search from there. [/EDIT] Go to a 4 blade prop. The extra blade creates lift in the stern. BTDT with my 2465. Ended up with better performance, less fuel consumption and higher cruise speeds than with the "factory spec" prop. PM me if you have any questions.
I'll give that a try. Seems good cuz the marina's will let me demo props so I can give em a try to test out your math. Appreciate the input. Cud just load the beer and throw out the people, for testing purposes. What's a gallon of beer weight - 6.5 lbs/gal?
