Topic: 1984 Evinrude 15 HP, newest motor I’ve ever owned – Page 2

This topic has 19 replies, 9 voices, and was last updated 9 years, 6 months ago by reivertom.

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October 5, 2015 at 1:16 am #25138
Casey Lynn
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US Member
Not simply a salt water issue on the upper grommet.
I have done a few in the last several years that are fresh water only engines.
The grommet will melt and fall over toward the center of the supply tube and restrict flow from that point on.
October 5, 2015 at 7:40 am #25150
Steve D
Participant
Ok Pappy thanks, I’ll be sure to give it a good look when I have the lower unit off.
October 5, 2015 at 10:02 am #25153
cajuncook1
Participant
I think Pappy is referring to inlet and outlet water tube grommets at the base of the powerhead. Review the article in this link regarding water circulation issues pertaining to the Johnson/Evinrude 9.9/15hp motors.

http://www.leeroysramblings.com/water_circulation.htm
October 5, 2015 at 11:01 am #25154
Steve D
Participant
Lots of good troubleshooting tips in that, thanks Cajun. I didn’t read it all through yet, but concerning those grommets…I see where they are in the diagram, are you able to tell if they are bad, or folded over by shining a flashlight up into the housing with the lower off?

photo storage
October 5, 2015 at 1:08 pm #25158
Casey Lynn
Participant
US Member
No…you can’t see them from the bottom of the exhaust housing.
The lower one almost always survives an overheat so that is not a tell-tale either.
Really can’t look at what the overboard indicator line is flowing at high RPM because the wind is blowing what stream there is apart.

Now the good part!
If you decide to take a look at it this would be the perfect time to replace all fuel lines, the overboard indicator line, clean the motor pan, and grease your shift linkage. The other bugger this engine has is the upper mounts….check them as well since they will be right in front of you. The only gasket you need will be the base gasket and of course two grommets.
October 5, 2015 at 1:25 pm #25160
Casey Lynn
Participant
US Member
This tuner assembly came out of a 1985 15hp. Above is a photo of what happens. By my thumb is the grommet that is at the top of the water tube.
The water pump was burned up, rubber transfer to the stainless housing was 360 degrees and the blades were gone off the hub of the pump.
After failure the opening in the grommet was less than the cross section of a BB. You can clearly see that the grommet has been burned and melted.
There was no evidence of corrosion between the tuner housing and the grommet on this one although that happens frequently.
The head gasket blew which allowed salt water into the cylinders and out the exhaust which is the white junk you see at the top of the tuner.
The powerhead was complete junk by the time the customer decided to take it in and repair it.
All fasteners came out easily. Customer stated it was an occasional salt water engine.
Since the powerhead was one of the black powerheads it showed nothing color-wise that it had been overheated.
October 5, 2015 at 1:54 pm #25162
Steve D
Participant
Thanks for the great visual Pappy, and the other info too! Now I know what to be looking for if it comes to that.
October 16, 2015 at 7:29 pm #25627
PugetSoundBoater
Participant
I have a 1976 Evinrude 9.9. Sweet motor! Salt water motor :replaced water pump ,thermostat,cleaned lower unit drain holes (Very Important to prevent water from backing up in exaust housing) ran OMC engine tuner through it. Runs great. I also add 1-2 oz of Seafoam per gallon. ,also flush motor with Salt Away in a barrel after running in salt water. Have fun with that great motor.

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson
October 16, 2015 at 10:08 pm #25632
fleetwin
Participant
US Member
quote pugetsoundboater:

I have a 1976 Evinrude 9.9. Sweet motor! Salt water motor :replaced water pump ,thermostat,cleaned lower unit drain holes (Very Important to prevent water from backing up in exaust housing) ran OMC engine tuner through it. Runs great. I also add 1-2 oz of Seafoam per gallon. ,also flush motor with Salt Away in a barrel after running in salt water. Have fun with that great motor.

The beauty part of the earlier models like yours is that they did NOT suffer with upper grommet problems like the later models.
The design of the water tube and grommet changed in the late 70s, which lead to the headaches. The main problem is that the newer style grommet is not fully supported (ID) by the water tube making the grommet vulnerable to getting mushed over by salt/overheat.
So, I usually don’t change the grommets on the early models unless there is an obvious problem, why introduce a problem. I purposely "mis-install" grommets on the late 70s-mid 80s engines to make sure the ID of the grommet is fully supported. The later 80s grommet/water tube set up was an improvement over the misengineered stuff, but still the grommet was not fully supported. I used to just cut off about 1/8" off the top of the "improved" grommets so the grommet was not taller than the top of the water tube. The last time I bought a new water tube, it came as a kit with a grommet, it appeared to me that they had raised the height of the water tube slightly to minimize the problem.
I wish I had some sort of drawing software so I could do a better job explaining this, because I know a picture is worth about a million of my words.
October 17, 2015 at 2:37 am #25644
reivertom
Participant
US Member
I was a Park Ranger at a local lake with a 10hp motor restriction back in the 1980s. If I wanted to have a bit of fun, all I had to do is walk around down by the boat ramp and show a little interest in these motors. I’d say at least half of this style motors that were on the lake were either 15hp with 9.9hp stickers or 9.9hp motors converted to 15hp. I really didn’t care one way or the other unless the guy was acting stupid on the lake, which was one of my "no stupid zones". I would walk up and say "man that little 9.9 really runs good" can I look at it?……I’d hum and haw a little and say, "nice motor…I’ll have to get me one of those…". You could see them getting nervous and trying to be calm. They were always happy when I walked away a said "be careful on the park road…watch for deer..". You’d look for something to do too on occasion if you were bored out of your mind….I didn’t care enough about camping regulations, etc., to be a good Park Ranger, so I didn’t stay there long.
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