How Much Horsepower am I pushing????

I have a 1977 115 Evinrude block assembly bored .030" over with wiseco pistons. I have the 135 Carbs,135 cylinder heads and 135 exhaust manifold on it. The motor is all fresh, just rebuilt last year. Holding a good 150# of compression on each cylinder. I was just curious on about how much HP this thing actually has?<br />Later:<br />Jason<br />P.S. If I go with the Boyesen Power Reeds, how much of an increase in HP numbers can I expect?

Re: How Much Horsepower am I pushing????

well, while all of these things might sound good they are not really dependable. sure they might last a few years but they will break. if I had to guess how much hp you were pushing out of that 115 my guess would be about 155 to 160 hp give or take 10 (just a guess) but the more hp you increase the more gas it wants to drink.

Re: How Much Horsepower am I pushing????

Hi, Jason.<br /><br />Why do you care? Unless I am mistaken, what you are trying to get is more speed.<br /><br />What did you do about port area and timing? Did you do anything to your ignition advance curve and max advance? Have you changed your prop pitch and profile?<br /><br />What is WOT speed, before and after?<br /><br />If you can give me those numbers, and the type boat you have, I can calculate an approximate hp for you. Don't be surprized if your new hp is only 120 or 130.<br /><br />The Boyesen reeds don't add hp. They allow more rpm, which makes more hp. Expect to replace them each 20 or 30 hours of WOT operation.<br /><br />Good luck.

Re: How Much Horsepower am I pushing????

If I'm not mistaken the 135 was a whole different beast from the 90-115-140 group. The 135 being a small journel as was the 85. I'd say its a crapshoot whether you get any horsepower boost from those add-on. Did you get the deflectors for the tuned exhaust or just the bubble?

Re: How Much Horsepower am I pushing????

JB, <br />I am just curious on how much power this thing is pushing, thjats all. The boat is a 1985 Sunbird. The wide open speed the last time I checked it was 47 @ 4900 rpm's. I have not had a chance to check the timing on this thing yet.<br />Walker,<br />I only got the bubble, no deflectors<br />Later:<br />Jason

Re: How Much Horsepower am I pushing????

Jason, you need more RPM's. You should be turning up around 5500. Check your timing at maximum advance. Might need a smaller prop to get the most out of that motor.

Re: How Much Horsepower am I pushing????

Unless I figured wrong, 1900 lb. loaded weight,<br />wot of 47, works out to about 117 hp.<br />@ 4900 you haven't even hit peak hp yet.<br />Get it up to 5500 - 5800. Should be a noticeable improvement in top end speed and more efficient at cruise.<br />Make sure link&sync is correct, make sure wot is actually wot physically. Carb butterfly's should be horizontal when wot.<br />Check installation of motor in relation to handling, higher the better, less drag (do a search on x-factor).

Re: How Much Horsepower am I pushing????

If you still have the 115 ports, you still have a 115(crankshaft sea level horsepower). At 4900 you are making about 80 (sea level) horsepower at the prop. Maybe. With 135 carbs you are making Shell Oil Co. very happy. To be running 47 mph at 12% slip you should be turning a 23" prop. With 15%, you should have a 24" prop. <br /><br />Boysesen reeds are the best. I have them in motors that have hundreds of hours on them (non-alchol/ no2 motors). When you get to 6200+ RPM, they will help.<br /><br />Best of luck!