1996 Evinrude 88 SPL increase in HP

Is it possible to upgrade an 88 SPL to a 112 or 115 hp motor or are there too many factors to consider.

I would figure carbs and exhaust but what else? I have a motor grave yard about an hour from my house and I can get almost any part I need with a little searching in their yard and warehouse.

Thanks for any info.

Re: 1996 Evinrude 88 SPL increase in HP

carbs exausht and I am pretty sure there are some things different in the block itself..best to sell what you have and get a 115..I have a 1995 I will sell..in great shape if you are near Savannah GA..if not I am sure you can find one near you.

Re: 1996 Evinrude 88 SPL increase in HP

Both engines use the same low compression bathtub heads, so the difference is in the porting of the block, the exhaust system machined on the powerhead back, and the carb throat size. To make a 115, you would have to tear the engine completely down and have a machine shop work on it to change it to a 112/115 block. If you are looking at the machining route, you may just want to locate a used 115 bubble back block and go from there. You may find that some bolt on components may increase your hp cheaper: add a set of NLA rubber intake filler blocks, a large set of 1 5/16" carbs and some old high compression heads from an early 140 crossflow. A set of composite reeds is a nice addition also.

Re: 1996 Evinrude 88 SPL increase in HP

the absolute easiest way is to sell your motor and buy the 115....10 X's less headache and worry....and spend the rest of the time you would have used looking around for parts, tearing down your motor, sending out to a machine shop and then reassembling what you have , then tweaking it.... going boating!!!!


or just buy the 115 stickers, and put them on your motor because i wonder if you will even go 5 mph faster in the end anyway


bob

Re: 1996 Evinrude 88 SPL increase in HP

I have the original 1977 115 that came on my boat and it will push the boat with the same prop 5 - 6 mph faster but that 115 is screaming. The 88 is much quieter and better on fuel. Not quite the torque of the 115 but I believe the 115 has lower gearing. I'll leave them both alone and keep a look out for a nice 120 or 130. My 88 is just about as perfect as an engine can be and especially for being 14 years old. It'll work fine for now.

Re: 1996 Evinrude 88 SPL increase in HP

Likely both engines have the 13:26 gear ratio. Both engines will have similar initial power, but the 115 will walk away from the 88 at higher rpm's. That 115 used high compression 140 heads, has larger carbs and has the NLA rubber intake filler blocks (good for 3-5 hp.) The older engine came with no rev limiter-the 88 rev limits at 5800 rpm. Yes, the newer engines make much better use of sound deadening in the midsection and the airbox than the older ones.

Re: 1996 Evinrude 88 SPL increase in HP

wiliermdb said:

I have the original 1977 115 that came on my boat and it will push the boat with the same prop 5 - 6 mph faster but that 115 is screaming. The 88 is much quieter and better on fuel. Not quite the torque of the 115 but I believe the 115 has lower gearing. I'll leave them both alone and keep a look out for a nice 120 or 130. My 88 is just about as perfect as an engine can be and especially for being 14 years old. It'll work fine for now.

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The newer motors (1985 and newer) are prop shaft rated for HP, the older ones crankshaft rated. That's a 5 to 7% difference. They also have a lot more low end torque.

Re: 1996 Evinrude 88 SPL increase in HP

Personally I would sell the motor I had and buy the motor I needed. Too many factors and hours involved for what may turn out to be marginal improvement.
Just my 2 cents though.