93 20hp to 30hp

[flangler]

I've looked around and saw a few threads about the topic, but nothing really answered my questions. I've been doing a lot of research and comparisons of schematics, and there is real only two things I know I need to change, and one I'm not sure of.

So I know I need to change the carb and manifold. But what I'm not sure of is the Bypass cover plate. Now for each motor they show a different part number for it on shop.evinrude.com. However on another site (that it won't let me post) they show the plate being compatible for both the 20 and 30. Would there really be a huge difference between the two? Doesn't seen much like a "tuner" part. Would the timing need to be advanced any? So any thoughts? Any help would be awesome, thanks!

 

[Bosunsmate]

Re: 93 20hp to 30hp

Bypass cover plates i only use when im looking at the rings to check they are still intact. Cant see how its a tuner part myself. Id buy the one that is specific for a 20 or 30 and just check it mates up to the covers right

 

[JB]

Re: 93 20hp to 30hp

So you think you will get a 50% increase in HP by changing the carb? Not very likely, Flangler. To get that kind of increase you will need to modify port timing and compression ratio as well.

 

[dkonrai]

Re: 93 20hp to 30hp

correct me if im wrong, but the wont the torque be the same? only the top end will change due to the increase in rpm?

 

[flangler]

Re: 93 20hp to 30hp

So you think you will get a 50% increase in HP by changing the carb? Not very likely, Flangler. To get that kind of increase you will need to modify port timing and compression ratio as well.

In my original post I wasn't asking if I I was going to get a 50% increase. I was asking if there were any other parts that I may need to change.

 

[JB]

Re: 93 20hp to 30hp

From 20 to 30 is not a 50% increase?