swapping powerheads

[gunlocators]

Ok I have 98 Model evinrude 115hp can the power head be changes or swapped for a 135hp powerhead and if so how far back age wise can the 135 hp be let say can a 89 power head be put in place of this 98 for example. Also if compatible what other issue may one run into. I will not be doing the work i would have a marine mechanic do it if this is even feasible. My goal is i want as much HP out of my bass boat as its rated for and i can go to a 135 the 115 runs good however i am looking for top hp for better performance

 

[emdsapmgr]

Re: swapping powerheads

I am assuming you have a 98 crossflow 115. No need to make the switch. The old 135 crossflow was hp rated at the crankshaft, your new 115 is rated at the propshaft. Little actual difference between these two hp ratings. If you want more hp from your 115, you can consider adding higher compression heads (from an older crossflow) and add the NLA intake filler blocks from an old crossflow 140. You will probably need to rejet the hi speed jets in the carbs. Composite reeds make a nice addition also.

 

[gunlocators]

Re: swapping powerheads

Great info now i need to find a mechanic that can do it I am wanting to sqeeze out a little more HP and if I can do it with out total power head swap then great!!!