20SF w/150 Evinrude Top-End

[rcnight]

Gents: Took the boat out to the lake yesterday and was hitting 40 mph at 5600 wot - one person w/less than half a tank. I'm running a 1996 150 Envinrude with a stock stainless 15x17 prop. Also have a T-top. How much of a difference will I see if I go up to a 15x19? How about engine mounting? How much foot should be below the hull? Does that translate into mounting holes? I have 3 holes. I'm now mounted in the top hole - or at it's deepest. Thanks for your input.

[Blue197320]

that seems pretty good to me. i had a 150 evinrude with no t-top and was turning an aluminum 15x17 and was getting 36mph at 5500 rpm. of course mine was an '85 and it was tired that was also with no tabs and had fishing stuff in the boat and 2 people.

The numbers sound about right or maybe a tad low. Mine runs 47 mph at 5400WOT with 150 ETEC and a 19 inch prop. But- I have a brand new engine so that might make the difference - also it's an ETEC which I believe may actually be a bit more horsepower than the stated 150.

[eggsuckindog]

Sounds like it could probably go higher - 1 to 1 1/2" above the hull bottom for the Cavatation plate. You probably could swing a 19 which would give you a higher cruise - although I would get the motor set up right and get a normal load in it and see what it does. If it is a 90' V6 rather than a 60' it likes it about 5300/5400 the 60' about where you are. Keep in mind that T Top is like a sail and the faster you go the more drag - 40 is very good though

[Blue197320]

i think the prop makes a big difference. i got a 200 merc and i top out at 44. engine trimmed up and t-top and fishing stuff and 2 people with full tank. thats at 5500. at the regatta it was flat calm on my way back in. then i could only get 48-4900 WOT and if i remember correctly 40 mph. that was ALOT of ice, 4 people, regatta toys. im running a SS yamaha 19p. gonna get rid of it. really really wanna hit 50 with 2 people on flat water.

[Bigshrimpin]

I had a 1999 150 Ficht on my 20 MA and I could barely break 40mph. Those 60 degree OMC motors seem to have a LOT of low end power, but don't breathe very well at high RPM. When I switched over to a 1981 Merc V225 with a 19 Mirage Plus and I could break 50mph solo easily.

If you want to go fast . . . find a 1986 or 1987 Evinrude 225 2.7L (bridgeport) or a 2.5L Mercury 200 (1991/2 Mercury 200hp 2.5L had the 7 petal fronts like the promax).

Older 1991 and earlier Mercury 2.4L 200's are a good compromise (great power to weight ratio) 83 and later 2.4L motors had fingerports, all 200's and most 175's were chrome bore.