At what level should I keep the RPM's when full throttle?

Question

I just bought my 1st boat, 18 1/2 ft Kenner 112 hrp. Mercury engine 800lbs max. Still in the breaking in stage. I am concerned about the the RPM's. I don't where the red zone would be.

Answer 1

Can you clarify the horsepower, Mercury doesn't build a 112 hp motor. It not sure, provide you serial number and I will tell you Monday what you have or you can call Mercury customer service with your serial number and they will inform you. 920-929-5040.

Mercury did not build a 115 EFI 2 stk, Only carb and Optimax. The roster tail should be long and low, if you can see it you are trimed to high putting the thrust of the prop to the surface of the water instead of pushing the boat forward.
The max rpm for the 4 stk will be 5000 to 6000 for the early model 06 and late model is 5800 to 6400. The Optimax is 5000 to 5750. 05 was the last year of the carb motor.

Answer 2

Give it some run in time probably 10 hours.Before full throttle runs at full speed . Check with Mercury Marine these electronic controlled fuel injected engines are governed not to over rev. Different props will change the rpms and how fast the boat climbs out of the water to full plane. It is a race on the lake where ever you go. And water ski boats need different prop to do that job properly.

Answer 3

merc serial number and model number sticker on the pivot bracket will state w.o.t. max rpm's you say breaking in still, so knowing they don't make a 112hp i am guessing 115hp. now there is a optimax 115hp, a 115hp efi 2stroke and a 115hp efi 4 stroke.in all applications 5500 rpm is a safe bet. but find the tag so you can be sure. now don't maintain w.o.t. for more than 5 minutes for 10 hours after that call it good. oh, the owner's manual covers all the breakin limits. you never want to go over max rpm. for rigging and setup i rec. 1/4 tank of fuel 1 occupant no extra junk like icechest in boat. trim engine til boat just frees up and steering eases. then accel to w.o.t. with small adjustment to trim. rooster tail should be same height as engine cowling or just able to see a little bit when you glance back to check. if very little tail then engine may need to be raised, up another hole or 2 or buy jackplate adjusting. if tail is to hi then trim in til it is at top of cowling. now don't overlook prop pitch, may need different pitch to obtain proper max rpm. either way when rigging or setting up then you want to be about 250 rpms under max with highest mph you can obtain from trim adjusting.

Answer 4

first 10 hrs is break in, change throttle position every 2 minutes, NO WIDE OPEN THROTTLE til after 10 hrs, then still keep that short too, if it's a two stroke add a LITTLE bit more oil to the fuel mix, use carbon guard "It's cheap insurance" the fuel now is so bad, it's cheap, and concentrated, so a little goes a long way 1 oz for every 8 gals of gasoline

Answer 5

I would assume its regular fuel engine. Maybe about 3500-4000 rpm should be good. If diesel, no more than 3000 rpm. Also best thing to do is read the owners manual. they would have that particular info in there.

Answer 6

use the boat you ll find out ,she will let you know,just remember you don't run you car wide open all the time..so don't try to run fast all the time,use the boat and get a feel,you can hear the motor you`ll know when it too much

Answer 7

Just go easy for a few months. Ask the vendor.
http://www.mercurymarine.com/