90 hp outboard

[Matthat]

I just purchased a used 17’ aluminum boat with a 90 hp outboard
Wot was 3500 rpm’s and ran great
Changed the prop now the wot is 4500 , ran great for a few minutes and started missing intermittently
Didn’t do anything other than change the prop
Any ideas?

 

[jgmo]

My first GUESS is that your tachometer.may be off.

You say it ran great at 3500 so I take it that you were happy with the speed both times.

If that's a Honda 90, the rpms should be up in the 5500 or even a bit higher.

I think 6000 is maximum.

If the tach is not reporting accurately, it could actually be hitting the rev limiter and cutting out because of that.

90hp is a LOT of power for a 17' aluminum boat so I can't say i would be comfortable at the speed that outboard could push that hull on plane. I'm a big chicken though.

Do you know what HP the transom is rated for?

Just an idea.

Good luck.

 

[WayWay]

I just purchased a used 17’ aluminum boat with a 90 hp outboard
Wot was 3500 rpm’s and ran great
Changed the prop now the wot is 4500 , ran great for a few minutes and started missing intermittently
Didn’t do anything other than change the prop
Any ideas?

JGMO is spot on with the RPM (attached are some spec that may interest you)