Printable View
I知 running this Mariner 150 and I知 getting about 50 mph gps. I feel like I知 under propped. I知 guessing it came with this 15 pitch stainless prop. I知 turning excess of 6000 at WOT. I don稚 have a Jack plate. Should I go to a 21 or 23 pitch prop?
Sent from my iPhone using Crappie.com Fishing mobile app
Attachment 397718Quote:
Originally Posted by minnerchunker
Sent from my iPhone using Crappie.com Fishing mobile app
21 would be a little steep if you are turning 6000 right now.
The ballpark rule is 200 RPM per 1 inch of pitch. To drop 500 RPM you would need 2.5 inches more pitch, 18 would be pretty close.
Thanks
Sent from my iPhone using Crappie.com Fishing mobile app
I have a 91 150 mariner. Running a 23p pitch. I get 54 mph at 5500 rpm. On a fiberglass ranger boat.
Sent from my SM-G781U using Crappie.com Fishing mobile app
Whatever you do, please don't over prop it. Nothing kills an engine faster than lugging it (which is what happens when it can't get up to it's optimum RPM range).
Not an experienced pro but I can tell of the one I had. 18’ Bumble Bee bass boat with the 2 liter 150 hp Mariner. I had a Laser II 25 pitch with the edge turned a little and it ran 60 to 63 with me alone and my RPMs were about 5500. Not a great hole shot but not terrible either. Good bow lift when trimmed. I also had a 25 Quicksilver with no edge work and it ran high 50’s and not as much bow lift. Tried other borrowed props and everything over revved, even the 27 pitch trophy 4 blade.
Running. 25 pitch high five on my 200 mercury,,, same motors I believe just bigger bore,,,
When I owned mine, I was told several things that may or may not apply. One was that a 200 hp front could be put on mine. I thought this odd as most of the 200’s I ever saw were built on a 2.5 liter power head and mine was a 2 liter. Props mostly interchanged but the diameter may have been different. That I never found out cuz the ones I had worked well for me.
I think at some point you’ll try a prop that keeps the rpms down enough and doesn’t take away your hole shot. I always spoke with everyone that had a setup similar to mine. Keep in mind, some of those folks didn’t have a clue what they had or why it worked good.
I ended up following the advise of the guy at my local boat store and bought a 19 pitch Solas prop. Mid 50's is ok I guess but it still turns 6000+ at WOT. I'm satisfied for now. Another note, I had to return the first prop I'd ordered because the prop housing was too large. We had to use the prop selector for a 115hp in order to find the correct size. I appreciate all the responses.
I'd be totally satisfied with that. Your motor gets MUCH less stress (therefore, longer life) being under propped vs over propped. Much better to be able to back off the throttle a bit and let the engine loaf than to have it lug trying to turn too much prop.Quote:
Originally Posted by minnerchunker
Based on your comment on the size of the prop hub, you have a Mariner "mag 2" outboard. The smaller hub lower unit is geared for faster turning of the prop and has lower water pickup for higher setup on the transom. The engine is actually a 2.4 ltr nikasil block . It was designed for the lighter bass boats at a time when 150hp was the limit set by many tournaments.Quote:
Originally Posted by minnerchunker
Having said that, those lower units are no longer available so have that one serviced regularly. I've setup a lot of those motors and ran one last summer on a champion 186DC. Unless you have a really heavy boat, a 24p prop should put you in the lower/mid 60s.
Thanks a lot sliderman!