1969 Evinrude poor performance?

[troa]

I have a 1969 Evinrude Sportwin 9.5HP Model 9922S that seems to be running at about half the speed that other users have reported.
I am running it on a 12 1/2' fiberglass v-hull that I estimate around 250lbs with around 500lbs people/gear/fuel/motor and it runs at about 6mph most of the time.
It never has a problem starting it and it idles and runs fine all day. I run this engine every weekend on Fri/Sat/Sun and never have any issues other than it is slow. I've noticed that sometimes it seems like it is running faster than other times so once I tested it during one of these times and it was doing 8.5mph.
I have looked at all the posts on here and each situation seems different and unique so I would like to know what if anything should be my next step?
I have tested the compression and each cylinder is at 69# cold and hot. I have read so much different interpretations about compression on this and other forums that I am thoroughly confused. Is 69# ok? Some say 65 and up while others say 100 and up.????
The old spark plugs were not wet but they were worn so I replaced with correctly gapped plugs.
The plug wires look to be in excellent condition.
I did replaced the fuel line as it was cracked.
The fuel hose and can are new and function properly.
I removed the prop and checked everything there, looks fine.
The water pump looks to be pumping fine. I was told that it was rebuilt last year for what that is worth.
I also check to see if each cylinder was firing by removing one plug wire at a time and both seemed fine.
One issue that I cannot find any info on is that I checked the engine after running for about 15 mins and found that the temperature was only 127 degrees using an laser thermometer. This seems low but like I said I have found nothing on what it should be. Is it possible that the thermostat is stuck open and could this cause low performance? It does pump water out of the "pee hole" as soon as it starts up. Some one told me that it should only do that once it heats up and the thermostat opens. Is that correct?
There are no obvious leaks but the carb. area looks to be moist, Is this normal?
I know that I need to pull the flywheel to check the points and coils and plan to as soon as I can purchase the tool. What should I look for and could my issues be there? Or is it more likely a carb issue.

I appreciate any and all help on this. If I need to provide any other info please let me know.

 

[Bluestream]

Re: 1969 Evinrude poor performance?

I don't think that engine has a thermostat. Mine was bought new and would pump water from the pee hole on start-up. Maybe the carb needs looking at?

 

[eavega]

Re: 1969 Evinrude poor performance?

That engine does, indeed have a thermostat. It sits at the top of cylinder head under the round cover with three screws. IIRC the operating temperature is between 125 and 163 degrees. If you are reading 127 degrees depending on the accuracy of your thermometer you should be okay. When you say you ran the motor for 15 minutes, did you run it WOT for 15 minutes, or did you let it idle for 15 min? I believe for a true temp test you need to be running it at over 4K RPM for 15 minutes to get its operating temperature.

Compression readings can vary due to testing techniques and the tester you actually used. Its more important that the readings be within 10% of each other. My previously mentioned 1960 10 HP read 60# of compression, but it was dead even on both cylinders. She would start on the second pull hot or cold.

You might want to get a tachometer on that motor and verify that you are running at a correct speed.

It may just be a case of you being right on the cusp of getting your boat on a plane, so any little factor like wind at your back, or some weight redistribution is enough to get the boat to plane up so you start moving faster and the engine winds up a little more.

If you are firing both cylinders (you said you performed a drop test?), you need to check your engine speed under load. If its not running at its recommended RPM, then you need to look at weight redistribution or lightening your load.

 

[F_R]

Re: 1969 Evinrude poor performance?

I don't think there is anything wrong with your motor. If you want to know for sure, beg, borrow, or steal a test prop and tachometer. That is how a properly equipped pro would test it. Er...rather than steal it, perhaps you would be better off paying the pro to do a test run. IF you can find one that has the test prop.

Personally, I don't think you have enough horsepower to plane the boat.