1979 115hp Evinrude, whats the max R.P.M?

[mrgixser]

hello again! could anyone tell me the maximum rpm for my 79 115 hp evinrude?thanx in advance for any answers.

[emdsapmgr]

Your engine was horsepower rated at 5000 rpm, with the "normal" operating range between 4500 and 5500. You should try to run the engine in the upper end of the normal operating range.

[Dhadley]

For the longest engine life on todays fuel (probably even more critical with 2006 fuel) the top target rpm with an average load is 5800.

[mrgixser]

thanx for the replies. i am only getting around 4800 rpm,s with my throttle opened all of the way. how can i adjust the throttle to get me to 5800 rpm,s without changing the idle speed. thanx

[ob]

If you're fix was as easy as a throttle adjustment,you'd be real lucky.Each engine with respect to what boat it is driving requires a specific set-up to achieve top recommended rpms at wide open throttle.The two critical items are prop selection and engine mounting height.A prop that is too steep in pitch or engine mounted too low on transom will result in excessive load and lower engine rpms.Conversely ,an engine mounted too high or not propped steep enough will result in prop ventilation and excessive rpms.Try providing some critical data.#1 Viewing boat and motor on trailer,where is your engines anti-ventilation plate(the one just above the prop) with respect to the bottom of the boat when the engine is trimmed down? Above? Below? Level?#2 Look for numbers on the prop that will reveal the diameter and pitch#3 what is the length,hull style,weight,of the boat in question. Post this info and someone will take it from there.

[mrgixser]

ok the only numbers i could find on the prop are 389512 1 3/4 and 21 dont have any idea what they mean. also the plate above the prop has settings on it 1-6 it is set in the center at #3. with the motor trimmed all of the way down the center of the prop is approx. 5" below the bottom of the boat. also the boat is a 1980 procraft fiberglass v-hull approx. 15'6" long. i could find nothing indicating how much the boat weighs. it has a 115 horse evinrude on it. any info is greatly appreciated. thanx

[Dhadley]

Does that Pro Craft have a stepped transom? Or does the transom go straight down the meet the bottom?

[mrgixser]

im sorry, im a new boat owner and i really dont understand the question.

[ob]

I think Dhadley means ,does the transom of the boat that the engine mounts to slope in toward the boat from top to bottom or is it more 90 degree angle with the boat bottom.

[mrgixser]

the back of the boat slopes in just a little from top to bottom, and the plate that the motor mounts too is 1" thick at the top and goes to about a 1/4" thick at the bottom.

[emdsapmgr]

What prop did the prior owner run?-if the 21 pitch prop ran at full rpm, then there is an issue with the engine. If the 21 pitch prop always ran at 4800 rpm, then the wrong pitch prop is on the engine-try going to a 17 pitch prop.

[mrgixser]

thanx guys. i put a 19 pitch prop on her and i am now running 5,500 rpm,s plus a lot better hole shot. i think this is the set-up i was looking for. thanx again to all of you that posted here.

[ob]

That's good news .