Evinrude 9.5 confusion

[Brento311]

Hi, I have a 1972 Evinrude 9.5hp that I used to ask about pretty freqently. Well now that it is fishing season again, I have more questions to ask! I am only 18 years old, so I can use all the advice that is given to me! Today, I took it out just to let it run a little bit, and something odd happened. I was in a small pond, so when I unhooked the gas line to let it run out of gas, I just left it in gear and ran around the pond wide open. When it got to the last bit if gas, it opened up like it never had before. It felt like I was holding the tiller on a brand new 9.9hp that was running wide open! It had never run that good before when I was using it. Then it ran out of gas, so I trailered it up. Earlier in the year, I cleaned out the carb real good(I didn't rebuild it because it was rebuilt by the previous owner 2 years ago), installed new coils, points, condensers, spark plugs, and plug wires. I just want to know why isn't it "opening up" all the way when I am out using it? Why does it only do it when it is on the last little bit of gas? Any help would be greatly appreciated!<br /><br />Brent

 

[FlyBoyMark]

Re: Evinrude 9.5 confusion

When the engine goes lean such as when you run the gas out at WOT, the engine will for a very short time put out more power, BUT, at the expense of your engine wearing or even breaking from friction. In the future, DO NOT DO THIS except at idle. There is a remote possibility that the carb(s) are not jetted properly but even so DO NOT DO the above again for your engines sake.

 

[ob]

Re: Evinrude 9.5 confusion

Brent, Listen to FlyBoyMark.Your two stroke engine relies solely on the fuel oil mix for its lubrication.Running it empty while running at any speed is asking for trouble.If you feel the need to evacuate carbs for storage in off season, I recommend draining carb bowls.If your engine is not performing as it should your carburetor float may need to be set a bit lower or the mixture may need adjustment.In order to perform this procedure I highly advise obtaining a service manual specific to your engine.

 

[Boatist]

Re: Evinrude 9.5 confusion

Brent<br />First I would do a compression check with the engine warmed up. Each Cylinder should be 90 psi or better. Make sure you have both plugs out and WOT.<br />My 1975 15HP Johnson, top cyl 127, bottom cyl 120 and each cylinder runs best at a different low speed idle mix. I supect your's will also. Way I checked it was pulled one plug wire and started motor then adjust for best idle. Then do same for other plug. Then I split the diference and it idle great. I supect this is caused by worn rings or reeds.<br /><br />My guess is you have a simular problem and one cylinder is running too rich. So when you were running out of fuel finally reached a point where both cylinder running with the right mix. Since only high speed adjustment is to change the jet and it will affect both cylinders I am not sure what you can do about it. One possible thing is to lower the float level a little in carb so requires a little more suction to get fuel but this will only make a very small change. I am not sure about your motor but on mine fuel pump run by crank case pressure and if get a bad diaphram will leak fuel into one cylinder which would make one cylinder run rich. I hope you get ideas from others that know your motor better. If you find the answer please come back and tell what it is.<br />Good Luck

 

[ronnie33]

Re: Evinrude 9.5 confusion

ask any racecar engine builder.lean fuel mixtures make big power numbers.for a little while.

 

[Brento311]

Re: Evinrude 9.5 confusion

Thanks for the posts guys! I'll know not to do that again! I am very familiar with the carb on my motor because I have done some previous work on it, but how do I set the float differently? Do I just bend it down until it is set lower? Also, my motor may be doing just fine, but I just don't know how fast it should be going. I have never seen a motor like mine run on anyone else's boat. What should the estimated top speed be on a 14'x36" wide bottom jon boat that weighs 185 lbs, plus me(200), my dad(about 160), and a battery and some fihsing gear? My motor is a 9.5hp. I also don't have a GPA, so I can't tell how fast I am going...I would just like an estimate maybe from someone that runs a motor like this, or has some experience with one. Thanks again<br /><br />Brent

 

[Neptune]

Re: Evinrude 9.5 confusion

Hi Brent,<br /><br />I used to have boat about the dimensions you described and it would run about 10-11 mph at wot. It was a pretty heavy fiberglass bihull. I have never seen one of those old low profile motors push a boat very fast but they always seemed to get there.

 

[Brento311]

Re: Evinrude 9.5 confusion

Neptune, that sounds about how fast I am probably going at WOT. I would like to use a GPS to see, but I don't have one, so oh well! You are right about it always getting you there. My motor starts on the first pull, and runs great for as long as I want it to. The other day, I was out with a buddy of mine that has a 2001 Mercury 9.9hp...his took close to 10 pulls to get started, when my old 1972 started on the first pull! haha They are great old motors aren't they!<br /><br />Brent

 

[Neptune]

Re: Evinrude 9.5 confusion

Yes Brent, they were dependable and sure fire one pull crankers. Wish they still made them like that <sigh>. Mine was used extensively in all kinds of places and never let me down.