yamaha F20plr can't get over 4200rpm

[tryn2lrn]

Just a quick question I spent the day breaking in my new 20hp four stroke, when I was able to try full throttle for short periods after the 2 hours of varying low rpms the motor won't go over 4200rpms. Now let me mention one important fact the motor is mounted on a 1400lb boat. Is it because of the big boat and constant load it's trying to move that the rpms won't go higher? Or should the motor be able to spin to the 5500 rpm limit no matter what the load or just standing still? If it is because of the load can someone give me some advice on a prop change. I really don't care about speed and know I won't plane the boat but it feels as if any rpms above about 3200 won't move the boat any faster and it sounds like it's working pretty hard at 4200 trying to move the boat. FYI I usually am on HP restricted lake that's why the 20hp. I was on a bigger lake for breakin and had a few miles to cover so I was trying to get all I could out of it. I would rather have a prop that had a bit more torque if I can only get up to 4200rpm.

Thanks for any help

[tryn2lrn]

stop spamming the forum

Idiot spammers

[99yam40]

report the spammers and state your prop you are running.Sounds like way over proped and that will hurt the motor

[tryn2lrn]

I have a 9.25 x 10 on the motor from the dealer. Which way should I be going? I am assuming I should be going down to like a 9.25 x 6?? Any guidance is appreciated.

Thanks

[99yam40]

lower will give higher RPM probably need to check the prop forum or do a search for what pitch you need. Sounds like way too big of a boat for that motor

[tryn2lrn]

you are correct that the boat is way too big for the motor. I am not trying to replace the performance of the 115 that came off.......I just want to make sure I am not hurting the new 20hp motor. I just want to make it as good as I can get it. It just didn't sound right and I know the the recommended rpm should be around 5500. So if I understand this correctly and I can compare this to cars or even better a 10speed bike this prop on the motor is like trying to run in 8th gear all the time with a 400lb rider?