Prop help

[kirmy22]

I have a 1972 evenrude 50hp it has a 13.25x17 prop pushing a 15 ft fiberglass boat , I don’t have a tachometer but my engine is not getting high enough rpm,s it’s not winding up like it should, any idea what prop I should be running. This is the original motor for this boat. Engine runs great just not getting enough rpm. Thanks

 

[kirmy22]

I have a 1972 evenrude 50hp it has a 13.25x17 prop pushing a 15 ft fiberglass boat , I don’t have a tachometer but my engine is not getting high enough rpm,s it’s not winding up like it should, any idea what prop I should be running. This is the original motor for this boat. Engine runs great just not getting enough rpm. Thanks

 

[alldodge]

Have you checked compression?

 

[jimmbo]

You need that engine to be running between 5000 and 6000 rpm at WOT, preferably in the Upper Half of that range.
You are getting what speed, about 29 -30 mph?
A 15 would probably be a better choice.

 

[racerone]

How did you determine that the engine runs " great " ??-----By ear or with a tachometer or dynamometer.----Agreed ---Step # 1 is a compression test !!

 

[kirmy22]

Compression is 150 top 151 bottom. And yes The engine runs smooth, no miss fire you open it full throttle and it just doesn’t get where it needs to be.

 

[tblshur]

just a thought have u pumped the primer bulb while at full rpm ?is carb butterflyies fully open and timing advance full:joyous:

 

[boobie]

Edit....