Rude 115hp

[joel45acp]

I have a '78 Evinrude 115 pony motor that runs great now that I fixed the kill switch. The darn black and yellow wire was cut for some strange reason. Anywho, I was wondering what can be done to increase the power output? As it stands, it pushes my 1994 Blue Wave 189 Tunnel Classic with me only at 28mph. Is that about right? I've played around with the motor tilt to obtain max speed. I measured this with my GPS. It does have a 4 bladed SS prop at the moment. How would it compare to a modern 115hp motor? Thanks in advance.

 

[emdsapmgr]

Re: Rude 115hp

Your engine was hp rated at the crank. The newer engines are hp rated at the propshaft. Possible your engine would be 8-9% less hp in the modern world due the rating differences. You could change to a set of 135 heads. (consider that you will probably need to rejet your mains when you do the heads.) Your engine already has the intake filler blocks, so there is not much more to be done without some block machining. (porting and the bubble exhaust system.) A set of composite reeds is a nice addition. They will help idling and midrange pickup. Maybe even a couple of hundred rpm on top. That engine will pull with a 135 till you get into the upper rpm ranges, when the 135 will pull away. You stand to gain the most by working on your engine setup: make sure the engine is re-mounted to the right height and that you have the right stainless prop. Prop the engine to run 5600 to 5700 rpm.