Mercury 15 or 9.9

[gofishin]

Hi, I am planning on adding a kicker to 2020 620FS Cup and wondering what others recommend for size, 15 or 9.9. I am seeing that many pros are running 9.9. Primary use will be for fall walleye trolling on Mille Lacs and P2/P4 on Mississippi River. My previous 620 had Etech 15 which I thought was a great motor. Really liked the ability to adjust rpm from handle.
For those of you who have a 15 or 9.9, your thoughts and recommendations please.

[Senderofan]

I went with a 15 hp Pro...…..When my rig was new, the 15 has an alternator with double the output of the 9.9. Helps keep the starting battery charged.....especially if you have power steering on the main motor. I do see that Mercury now has a 9.9 Pro with the same alternator as the 15....but in a remote configuration......so pick your flavor. Guess the one with a tiller handle has the 6 amp versus 12 amp alternator.

[gbin]

I got the 15 hp kicker for my 2020 620FS Cup, and I like it very much - but I honestly think the 9.9 hp would have served me just as well.

Gerry

[MikeG1]

The EFI models for the 9.9 and 15 have exactly the same alternator output……. 12 amp….145 electric watts.

[clawman]

Originally Posted by MikeG1

The EFI models for the 9.9 and 15 have exactly the same alternator output……. 12 amp….145 electric watts.

That being @ WOT. The more RPM's your motor turns more output. I have a 9.9 on my 621 and that pushes it just fine even pulling cranks. If you spend more money it is not a sign you love your boat more

[gofishin]

Thanks for the replies. From Mercury specs it appears the 9.9 is a de-tune of 15. Clawman do you fish and rivers, wondering if 9.9 will push your 621 against current.

[kswalleyer]

15 for me....if ya need to get back to the ramp its a bit more. mine does 6.5 mph at WOT on 621

[Senderofan]

Originally Posted by kswalleyer

15 for me....if ya need to get back to the ramp its a bit more. mine does 6.5 mph at WOT on 621

I should have also said this.........we used our kicker to limp back to the boat ramp after a prop strike with the main motor. about a month ago We can manage @ 6 mph at WOT with our 15 hp....not sure what a 9.9 would do....but we are a tinny and have more resistance because of our rivets. Some of the areas we fish are 40+ miles from our launch. A couple of mph's might not seem like a lot.....but in a semi emergent situation????

[egladding]

I had a zv18 and installed a 15hp efi kicker. I fish musky and walleye and troll against river current. The 15 was a must to get up above 4mph when trolling musky. My buddy has a 9.9 on his 620 and it works good going downriver but has to run full throttle to troll upriver above 4mph. For the little extra the 15 costs, it shouldn't even be a question.

[K Gonefishin]

I had a 9.9 on my 621, now have a 15 EFI, buy the 15 IMO. Great motor.