Need to replace prop on 81 Evinrude 25 hp

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Osageinmt,

Glad to read that you're on the right track to boating perfection. You need to dial a transom shim height that when alone at close tight turns prop doesn't aerate. Know that pulling head out transom to check water flow passing by lower leg can be intimidating, includind dropping cameras, cel phones into the blue, could ask another boater to ride side to your transom and check lower leg condition.

Check with you alone same as on your last outing new 10 pitch prop, that will surely put you on the max 5500 wot rpm with good top speed, wot rpm will drop accordingly when extra family members are added. Would you say you have achieved an increment of around + 500 rpm while boating with you alone and lightly loaded when passing from 12 to 11 pitch ?

Post final results with 10 pitch, that's you alone and then with family members added to check rpm difference under both modalities. Just for the record.. This is the sweet engine/transom height example I like using, try to dial same and boat happily forever under all water cond.

https://www.youtube.com/watch?v=oBeZjaA76VM


Happy Boating
 
Last edited:

osageinmt

Seaman Apprentice
Joined
Jun 9, 2015
Messages
35
managed to get the boat wet with the 9" X 10p prop today. I put it in the river which is not something that I have done in the past myself and another guy, gas, batt, etc: I could turn 6000 + anytime I wanted...did it a couple times, didn't really mean to. it really reved I could hold it around 5400 to 5500 with ease you could just feel it wanting to go faster.

the max rpm today was 6043 top speed by gps was 21 mph.

I never opened it up we were just easing along looking for sandbars, and I did manage to find one. Only going about 2-3mph when I ran up on it, pushed it off and went on our way up river.
Not a lot of water in the Missouri around here this time of year.

too much prop maybe for just me and the wife in a lake, but will be great when I fish with a 300 + size guy in the boat. I'll go back to the 9.25 X 11 prop, I'd rather run at the lower part of the rev range, than run it 6500 rpm any time you weren't really paying attention. if you blink it's 5200 then 6000 rpm quick.
 
Last edited:

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Are you revving 6500 metered revs say you alone and lightly loaded boat with a 10 pitch prop ? What about same cond with a 11 pitch one ?

Happy Boating
 
Last edited:
Top