I have a 15x21 3 blade on it now, when tach was working, it would turn like 4,800 rpm's. hole shot sucks ass. I researched and found that a 13 1/4 x 20 is all around prop. I am just trying to get info from anyone using this engine and what size prop they run. Thanks

Find out whats the Max Reccomended RPMs that motor can turn. Too much prop is gonna put more strain on your engine.

Will check the prop on the 90 Mariner when I get back down to the camp. What size boat you running it on? Jack plate?

Express 17ft CC , no jackplate. Boat will plane alright not under load; tried to pull a kneeboard and a tube and with 5 people in boat, it was not getting up at all. I read enough to figure the diameter is too much already, sounds like i have a low pitch v6 propeller. just running it did turn like 5200-5400. But I am not out for speed, need hole shot for water sports and fishing loads.

Thanks for the replies, i shall just check with The Prop Shop in Lafayette, they know their stuff.

a tube and a kneeboard is alot more to be pulling out the water that you think plus 5 people in the boat thats a good load for a 90

Used to pull a tube and a kneeboard with a 40 merc all day long with 3 to 4 people in a boat, had a 13 pitch prop and was a 17 ft crawfish skiff. So with right lower pitch propeller, that 90 should pull that with 5 peoples in boat, we not huge folks either , so guessing boat load around 800 lbs total with icechest and etc...... We used to pull 2 kneeboards with a 25 and 2 in the boat.

i just seen my 90 struggle before with about the same load in a 19ft carolina skiff it did it but it wasnt as easy as just 1 or 2 people in the boat was all im saying

I gotcha, fiberglass heavier than aluminum also. I get your point exactly though, if you was to go with a lower pitch prop, you lose top end, but gain low end power and mid range power. thats where I am at, need low and mid power not speed.

yeah on the carolina we had a 13x19 but now on the 1860 alweld it takes a 13x21 and it and does in the low 40s on both boats hope this helps at all