My 2000 merc 90 redlines at close to 6000 rpm. I usually cruise at 4500 to 4800 rpm and on calm days I run at 5000 rpm. I have over 2000 hours and last winter had the motor gone over and its great (compression etc). Most of the hours are trolling but lots running. I bet once you troll with your 60 you won't use your kicker. The fuel burn is less that 5gph at 5000 rpm. My buddy runs his yam 115 at 5000 all the time and he is well over 2000 hours.
My Last Boat Build
- Thread starter spring fever
- Start date
spring fever
Well-Known Member
I'm beginning to think that's going to be the plan- weight distribution' -best prop possible (Is it worth going stainless) and running at 1/2 fuel-I have a 25 gal tank which is a lot of weight on a boat of this size. I should also mention it was tested in a lake not the ocean- which may change things a little
RiverBoy
Well-Known Member
what’s the weight difference between the 60 and 90? I know you got the boat built for jigging upfront , but what if you go out to say, sentry or grants and the winds picks up and you have to cross back over with some big waves coming at you. might want that extra jam to power you up and over the hills. i dunno. food for thought
ExFlyGuy
Well-Known Member
I should mention the boats were lodge boats and I only ran them. They were run with full fuel all the time and with 3 guys.
I would wait to do any prop changes until you test it in the salt and see what your max rpm is there.
scott craven
Well-Known Member
The short answer is yes.
Less flex = better hole shot
MikePA
Well-Known Member
I was told when looking for a prop for smaller engines in the past that below 150hp the engine isn't putting out enough torque/power for it to matter. Not sure if that's true or not.
Rain City
Crew Member
I think there's something to that for sure. You could go nuts and get one of those fancy $2000 props and that might do it.
spring fever
Well-Known Member
That is my concern-I know me --I don't always take the first weather hint especially if the bite is on. Watch this space-I am on the trail to fix this. The weight difference is about 120 lbs. Don says it will drop the boat 1/2 inch
scott craven
Well-Known Member
Sure worked on mine, no longer needed a dole fin
RiverBoy
Well-Known Member
oh wow i didn’t know it would be that much heavier. same as the gas thing though. i’d rather have mucho gas on board. wonder how the dealership ( i’m assuming bill howich ) would feel about a trade in already.
i had a buddy that repowered his whaler with a yammy 70 hp 4 stroke and hated it. put all sorts of props to try and get more power. the dealership ( not howich ) was quite accommodating as they were trying to avoid the inevitable from happening. he eventually traded it in on a 90 which was max rating for the boat and just that little bit made all the difference.
i’m not a prop expert by any means. who knows maybe you hit on the right one and this is all for nought
Aquaholic
Crew Member
Aquaholic
Crew Member
You have the command thrust lower unit, so it carries the larger V6 prop selections. It already pushes a lot of water with the larger diameter props. I hope you get it sorted.
Does it need stern lift, or just some pop to get out of the hole? I think the max rpm for the CT version is slightly less than the standard leg. Make sure you're using that spec as you try to prop for max rpm's. (edit...rpm range identical for both versions)
Mercury says: Command Thrust (CT) models have a gearcase with a larger torpedo and a bigger-diameter prop. CT can lift a heavy boat onto plane more easily and hold it there at lower speeds without impacting top speed.
Available Command Thrust gearcase for 40 / 50 / 60hp Four Stroke models offers more control, improved hole shot and enhanced mid-range power. The combination of a gearcase that sits deeper in the water, a bigger prop with 20 percent more blade surface, and lower gear ratio provide unmatched thrust, maneuverability and boat lift.
Your CT 60 weighs 260, the 90 and 90 CT weigh 359 and 363 respectively.
Does it need stern lift, or just some pop to get out of the hole? I think the max rpm for the CT version is slightly less than the standard leg. Make sure you're using that spec as you try to prop for max rpm's. (edit...rpm range identical for both versions)
Mercury says: Command Thrust (CT) models have a gearcase with a larger torpedo and a bigger-diameter prop. CT can lift a heavy boat onto plane more easily and hold it there at lower speeds without impacting top speed.
Available Command Thrust gearcase for 40 / 50 / 60hp Four Stroke models offers more control, improved hole shot and enhanced mid-range power. The combination of a gearcase that sits deeper in the water, a bigger prop with 20 percent more blade surface, and lower gear ratio provide unmatched thrust, maneuverability and boat lift.
Your CT 60 weighs 260, the 90 and 90 CT weigh 359 and 363 respectively.
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spring fever
Well-Known Member
Yes it is
Squire
Well-Known Member
In the 70s and 80s it was the rare fishing boat that achieved 40 mph and running near max was the norm. The two-strokes of the day were typically run at one audible notch under max rpm.
The OP may benefit from a four blade prop of 2-3 inches less pitch in order to achieve manufacturer recommended max rpm. The online Mercury prop selector tool is a good resource. You enter your WOT with the current outboard model and prop combination and it generates prop suggestions that may get you closer to manufacturer specs. I would try this before giving up on the 60 hp
Aquaholic
Crew Member
do you have enough hours on it to do a sustained max rpm run to see if it is getting to redline?
spring fever
Well-Known Member
Well guys-you can't "Make a silk purse out of a Sows ear"-The boat turned out to be all I had ever envisioned and I knew it was underpowered the second I pushed it up. No amount of proping and travelling at half fuel was going to fix it. Outboards are scarce so I lost very little when I traded back-couldn't get a 90 buut there was a 115 with the right leg!! Just have to tow to van and swap in about 11days-going to be a long wait!!!
Rain City
Crew Member
Great news
Corey_lax
Crew Member
Same weight from 90hp-115hp so might as well go big or go home.
