evinrude 115hp WOT?

[gator68]

I'm running a 17ft v hull. 115hp v-4 2 stroke 1978. the current prop is a 19 pitch. I have cranked her up to 6500 rpms and there was some room left to go. Is my tach way off or can this motor turn that many rpms. The hole shot is good and I can cruise at 4000 and keep it on plane. The speedometer says that I am only going 30 mph at 6000 rpms. I am looking at replacing the prop soon because the one on the boat looks orig. any sugg. thanks in advance.

 

[ZOTMAN]

Re: evinrude 115hp WOT?

I also have a 115 Evenrude on a 17 foot glass. Similar pitch and it will do 55mph trimmed out. Something does not sound right.

 

[rdgallo]

Re: evinrude 115hp WOT?

I think that I would verify the tach reading. I am no expert, but I think doing 6500 rpm on that motor is not good. I also have read on posts that some of these engines have rev limiters on them that will not let you achieve the rpm you are getting which would point to maybe an inaccurate tach reading. Again I am by far an expert. Maybe an expert will jump in here and straighten things out.

 

[walleyehed]

Re: evinrude 115hp WOT?

1978 115 has no rev limiting pack...<br />If Tach was correct, with a 19 at 6500, you'd be about 53-54MPH....Your key to the Tach being off is the fact you say at 4000RPM it will still stay on plane....It darn well should at 4000RPM, that's ABOVE economy cruise. "If" your tach was right, at 4000RPM, you'd be around roughly 33MPH...WAY above plane-speed. Good indicator your tach is off.<br /><br />ZOTMAN...If you are using a 19P as well, and truely getting 55MPH, your in the 6400-6500RPM range as well...The engine is just an air-pump...if good fresh fuel and good oil are used, I can't say it will come apart, although I'm not sure with stock stainless reeds, you wouldn't have a bit of reed float before that RPM, like maybe 6200-6400????

 

[gumball]

Re: evinrude 115hp WOT?

wow i have a 1973 merc 150 inline 6 and can only get about 5000 rpms with an 19 pitch prop on a 18.5 1969 glastron, first time i had it out i got it up to 45. had to bring the motor up a bit because the boat would vere one way or the other.

 

[Boilermaker]

Re: evinrude 115hp WOT?

I have a 1978 Johnson 115, on a 17.5 Ft Modified Vee Fiberglass hull (1971 WestWind). I am running 17" props & turns around 5300 rpm. I am working on the setup to try & get it up around 5600 Rpm or more. It starts to fall off plane at about 3000Rpm.

 

[gator68]

Re: evinrude 115hp WOT?

sounds like my tach is off. the motor sounds normal at 6500 rpms not like its going to blow.It feels like about 50-60mph but on the water things seem faster than they are.thanks for all the info. i looked at the calibrator in the back of the tach and its set on 4 cyl. The engine has been rebuilt a few yaers ago before I bought the boat. I don't know if any thing has been changed

 

[Dhadley]

Re: evinrude 115hp WOT?

If its an E/J tach it should be set on position 6. It has nothing to do with the number of cylinders. The tach reads the pulses of the charging system.

 

[gator68]

Re: evinrude 115hp WOT?

alright I will check that out. Looked at tach and there is not a name on it. just a picture. I will look on the back in a few days. Working 6 days 10 hrs a day right now. High heat and humidity!I need a vac...

 

[Mercathode]

Re: evinrude 115hp WOT?

many runs at 6500 rpm , this old veteran will swarm on ya!