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Author Topic:   90HP Evinrude eats jellyfish, now over heats.
Chuck Tribolet posted 07-21-2012 07:03 PM ET (US)   Profile for Chuck Tribolet   Send Email to Chuck Tribolet  
Executive summary: The cooling system on my outboard
ingested part of a couple of jellyfish, and now it overheats
at idle.

The motor is a '97 Evinrude 90HP carbureted two-stroke V4
with about 1200 hours.

This morning at the launch ramp there were lots of
jellyfish. Adm. Linda starts the motor and lets it warm up
while I park the trailer. The salmon bite is on, so things
are busy and I had to park in the upper trailer lot, which
is a bit of a walk, so it idled for quite a while. Just as
we got set to shove off, the overheat alarm went off. I
tipped the motor, scraped the Jellies off the intakes. And
cycled the motor on and off a few times to cool it down.
The overheat light went out. We shoved off, but only made
it about a mile (mostly idling because of a no-wake zone
and then a nice pod of dolphins). Since we were right at a
passable dive site, we dropped the hook and shut it down,
and went diving while it cooled off. After the dive we
pulled the hook, fired it up, and headedb back to the
harbor at speed (about 3/4 mile), then through the no-wake
zone (1/4 mile) at a touch faster than idle. Just as we got
to the dock, the overheat alarm goes off again. No jellies
on the intake. There's a hose there, so we hooked it up to
the flush port on the block (which after the impeller and
before everything else), and flushed it well, and ran the
engine some on the hose, including some 2000 rpm in
neutral. We then headed out to do a second dive on a nearby
site, again about 1/4 mile of idle, 3/4 of a mile at speed,
then idling to find the dive site. After a couple of
minutes of idling, the overheat alarm goes off. We decide
to call it a day. We cycle the motor a couple of times to
cool it off, and head in. I think the overheat alarm went
off again just as we got to the dock.

We pull the boat, I pull the intake screens off, no jelly
behind them. At home I flush the heck out of it using the
port on the block. The intakes flow really well on the hose.
The outlets flow some, but they never flow as well as the

It seems to be happy running at speed. It overheats at


Chuck Tribolet posted 07-21-2012 10:26 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
It's got a good telltale stream, so I don't think it's the


PeteB88 posted 07-21-2012 10:53 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Sounds like me a week or so ago - no jelly fish in Lake Michigan. I had reasonable telltale too but mechanic inspected the parts and said impeller was shot. Unless those organisms cooked themselves to cooling pathways not sure if boiled jelly fish thicken up like gelatin.

Good luck - I still have not powered up my motor - busy on project, but plan to next couple of days. Mechanic suggested I take garden hose and shoot some water into the pipe with the lower unit off. Did so, nothing whatsoever rinsed out of the motor.

I think our motors are much more sensitive to ingesting gunk, sand, weeds than my Yamaha for sure. Yamaha has never once flinched when in muck and muddy/weedy conditions.

Keep us posted.

lizard posted 07-21-2012 11:48 PM ET (US)     Profile for lizard  Send Email to lizard     
You know, Chuck, you would think if something is jamming up the impeller, that you would have problems at speed as well. I can't help thinking about the long tentacles on jellyfish and wonder if they are an issue. When did you last do a lower unit service and did it include the impeller?

Chuck Tribolet posted 07-22-2012 01:27 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
It's been a while since the impeller was changed out, and
that's on the list to do on general principles.

However, tonight, I pulled the thermostats out (It's easy on this
model) and one is stuck open and the idle vents are clogged
on the other one. So that's one todo for sure.

Tomorrow, I'm going to use the flush port first with the
thermostat caps off, and then with caps on but no thermostats
which should give me really good flow through the heads
and flush out any jelly that might be in there.


PeteB88 posted 07-22-2012 02:28 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
I guess I better get an illustration of thermostat location on my 94 Johnson 115. Or web search.

Standing by....

Chuck Tribolet posted 07-22-2012 07:53 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
PeteB88: Your 115 is a 60 degree V4, right? It's probably
the same as mine: At the top center of each head is a black
plastic widget with two sets of hex flats (one 1 1/2", one
13/16"). That unscrews (USE THE BIG SET OF FLATS, you'll
break it if you use the little set, and there's no warning
about that in either the factory or Seloc manuals) and the
thermostat is underneath the cap.

Note: almost all of my motor time has been in salt water.


Teak Oil posted 07-22-2012 07:59 PM ET (US)     Profile for Teak Oil  Send Email to Teak Oil     
If memory serves the thermostats are two gray pods in the middle of the block between the cylinders.

Here it would be above and behind that module on my 1985 V4

PeteB88 posted 07-22-2012 08:57 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Well, here are fresh images of my motor - my several hours of web time today indicate my motor is "bubble back" design. Chuck, note from photos, my telltale connects to what appears to be a 1/4" barbed fitting and not a nice hose connection.

My guess is the thermostats are buried under that steel bulge but not yet sure. I am also considering pulling the clamps on both hoses that fit into the manifold (ECU photo) below the bubble.

Standing by for any help. [Absurdly long URL deleted--jimh]

PeteB88 posted 07-22-2012 09:01 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Sorry about the link -

Chuck Tribolet posted 07-23-2012 12:37 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Teak Oil: Yours is old enough it must be a 90 degree V4.

Mine is a 60 degree V4. I'm not sure when OMC changed over
to 60 degree. I thought it was about '92, but Pete's pictures
sure look like 90 degree. And they look NOTHING like the
back of my power head.

Pete: I'd suggest going to and drill down to your engine and see where the
thermostats are. If you think the pictures are little, find
the enlarge icons. BTW, I didn't order parts from tonight because their only shipping option
is 3-7 days, and I gotta have the Montauk back in the water
Friday afternoon (big photo contest coming).


seahorse posted 07-23-2012 07:29 AM ET (US)     Profile for seahorse  Send Email to seahorse     
The 60° V4 was introduced in 1995 and the 90° was still produced for several years after that as the economy outboard in 88, 90, and 112 hp models.

On a V4, if the pan mounted trim button is on the stb. side it is a 90° motor and the 60° models has the button on the port side.

PeteB88 posted 07-23-2012 09:36 AM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Yep - buttons are on stb side, so must be 90 degree - now what??
PeteB88 posted 07-23-2012 09:49 AM ET (US)     Profile for PeteB88  Send Email to PeteB88     
My guess is the thermostat(s) is located at the bottom of the photo where two hoses enter what is likely to be the thermostat cover. Now - question - do I pull all that appart to inspect for crud and replace thermostats, assuming I have located them or leave it?

Also - where can I find torque specs besides a real shop manual? Where can I get a real shop manual?

Thanks, standing by and best to all.

seahorse posted 07-23-2012 12:22 PM ET (US)     Profile for seahorse  Send Email to seahorse     
Replace the thermostats, gaskets, and grommets. Make sure the white plastic pressure relief valves are free.

The torque on the 1/4-20 bolts is 5-7 ft. lbs or 60-84 in. lbs.

File a very small notch in each white valve to help drain the thermostat housing and to bleed the air quickly when starting up the motor.

PeteB88 posted 07-23-2012 12:52 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Thanks big time.
Chuck Tribolet posted 07-23-2012 03:15 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
I got my factory service manual (FSM) from an Evinrude dealer a
while back.

The Evinrude online site sells them from 1997 forward, and
says: "For Evinrude service manuals or Evinrude Johnson owners manuals for 1996 models and prior, please contact the Ken Cook Company at (414) 466-6060 or click here to be directed to their website Antique Literature. " which
resolves to: .

The Seloc manual covers basically ALL the V engine Evinrudes,
so there's a lot that doesn't apply to any one given engine,
but it does some tricks that aren't in the FSM.


PeteB88 posted 07-25-2012 01:02 AM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Thanks Chuck and Seahorse - pump works great however one side's hotter than the other and I started a new thread thinking the experience might help someone else. It's going to be a few days before I can get to the boat - definitely going to get new themostats but worried that something else is plugged up.

best to you guys. and thanks

Chuck Tribolet posted 07-27-2012 12:39 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Linda picked up the last parts yesterday, then we had to go
back to get the right thermostats. (Although I have an
A-suffix model number it needs C-suffix thermostats). I
replaced the thermostats and retorqued the heads last night
and did the waterpump last night and this morning. The
hardest part was figuring out how to get the shiftlever
loose at the powerhead end. I had to disassemble a bit of
the linkage to get things to move far enought for it to
come loose.

There was no smoking gun in the waterpump. It actually looked
pretty good.

I still have to put the gear case back on, and pick up a new
bolt for the anode (it broke, 1400 hours in saltwater will do
that. Will get it tested in the water this afternoon.


PeteB88 posted 07-27-2012 01:18 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
If the shift rod is like mine there is a clevis pin you pulled when you removed the gear box. The rod has a hole in it at distal end. When you reinstall (grease the gear first) what worked for us (two person operation) is to 1) make sure shift rod is properly oriented to engage shift mechanism and pin once installed (expect it to rotate slightly), 2) tilt motor almost full up, 3) with helper, ease the lower unit back in place, while you very slightly rotate flywheel proper direction until shaft meshes with power head - very easy 4) once in place use good flashlight to determine orientation of shift rod, 5) checking at the bottom of the lower cowling and forward edge of the motor shaft you will see an access spot/gap where a few centimeters of the SS shift rod is visible 6) you can rotate the shift rod with long needle nose pliers from that access point while observing above. 7 locate the hole where clevis is inserted in horizontal pin that engages the shift rod 8) once you confirm how things are supposed to fit together, position the rod, shift mechanism and pin and once in place pin it in place with clevis pin.

My neighbor, retired tool and die man, figured it all out and spotted the hole in the shifter where clevis goes - he jumped in and bailed me out, I was the helper.

We used a AA Pelican LCD light with very focused beam to identify all these components and holes.

The key was finding that access port below the power head so we could position the rod once installed.

Chuck Tribolet posted 07-27-2012 04:52 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
I could see everything (sorta) and get things lined up, but
it wouldn't quite go. When I removed the side plate on the
starboard lower carb, I could move things about 3/32" further
and I was done in 90 seconds.

I just ran it at idle for 20 minutes in a big tub of water.
No overheat. And "cooling" water was up to about 90F by the
time I shut it down.

It may have been my imagination, but it seemed like the
tell-tale stream was stronger. So maybe it was the water

We're off to test in the ocean.

Thanks all.


PeteB88 posted 07-27-2012 05:23 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Excellent - telltale on my motor was significantly stronger - no question. Going to get into it tonight and tomorrow to determine what is making right side hotter than the left - When I ran mine no audible alarm but still too hot to run.

Have a great time.


Chuck Tribolet posted 07-27-2012 07:46 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
It passed the sea trial just fine. Dive tomorrow.


PeteB88 posted 07-27-2012 09:36 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
I envy you Mr Tribolet- how cool.
PeteB88 posted 07-27-2012 10:47 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Actually I should have said - it would be cool to follow you guys out to your dive spot. To be clear, Lake Michigan is pretty boring compared to Pacific - and lifeless. It is not a prolific marine environment as your waters in any way. Although the water at the beach is high 70s and that's kinda cool.

Chuck Tribolet posted 07-28-2012 08:59 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Well, we had 47F on the bottom last weekend, IIRC.
And pretty lousy vis.


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