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Evinrude 120hp V4 1989 model - Over Heating!

S

scare_crow_69

New member
Hi Guys,

Yesterday i pulled the boat out after sitting in the shed for over a year. I cleaned the cylinders out, ran new fuel etc

I started in the yard with muffs and started straight away, ran a little smokey but soon cleared up after it cleaned itself out a bit. Water wasnt 'streaming' from the pee hole but its was coming out (which is usually the way when using muffs). All looked great. It was idling great, was responsive, everything seemed normal.

I took it out in the river and hour later and again it seemed to run perfect. I headed up river sitting on about 35m/hr (thats what speedo said, RPM meter not connected yet but wasnt revving hard) and after 10 minutes the heat alarm sounded.

The entire time the boat was moving water was streaming out of the pee hole quite fast and the flow gauge showed the water flow to be where it should be.

I took top off the outboard and the cylinders didnt seem too hot. i could put my hand on each one for over a second before i had to remove it due to being hot.

i let it sit for 10 minutes and started it again. It started fine, and the alarm was not sounding anymore. I headed back the boat ramp slowly (at about 25m/hr, just so the boat stayed on the plain) and it was fine. It took me probly 15 minutes to get back and it ran fine the entire way back. Again water was streaming out of the peehole and the gauge showed the flow to be where it should be.

Any ides why it 'seemed' the overheat...? Did it overheat (it has never overheated in the past)? and water flow seemed to be spot on...

Any input would be greatly appreciated. Cheers, Chad
 
Water could seem to be shooting out the water outlet telltale when the water pump impeller is just starting to fail. The usual symptom of failure shows up at the higher rpms. Unfortunate that you didn't attempt a repeat of the problem to verify a high rpm problem.

Rather than chance a ruined outing, it's best to drop the lower unit, dismantle the water pump, and at a minimum, replace the impeller if for no other reason to eliminate the water pump as being a possible problem area.
 
Ok will do. I was told that in the older engines (with ruber impellers) the impellers can go brittle after long periods of 'out of water' time. i just though because water was coming out of the telltale that is must have been ok. Thanks for the heads up.
 
I have removed the lower unit and checked the impeller. It seems to be in great condition... almost new condition. It has no marks on it, and is extremely elastic. There was a fair bit of sand around the place in the lower unit but it was very clean inside the casing of the impeller. The key way looks a little worn but it should still do the job. I might take it all into a marine mechanic and ask for a bit of advice. Cheers, Chad
 
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Is there another reason why it could hav over heated? Did/does it just need a good run to burn out the gunk in the engine? i might need a bit of on the water time...
 
The alarms usually sound when the cylinder heads reach 200-212 degrees. If it was truly that hot, you would have burned your hand on the cylinder. Joe is correct in that changing the water pump is good practice after a long period of non use. It's cheap insurance to put a new one in. As for the alarm, I'd start tracing wires. Is anything cracked or exposed? Possibly mouse chewed? if the tan wire touches a ground anywhere on the boat the alarm will sound. If this is the case, it's interesting that it stopped when you shut off and restarted the engine. Another possibility is a failing temperature switch that tripped at too low of a temperature. If the water pump doesnt solve your problem, I'd go buy and inexpensive IR heat gun. That will aid in troubleshooting, as you will have a reasonably accurate temperature measurment.
 
I am assuming you know the correct horn sequence, if not here it is http://continuouswave.com/whaler/reference/warningHornSignals.html
I have seen an instance where the plastic housing of the water pump develop a hair line crack right along the outer rim, with the LU off use a garden hose and pressurize the housing of the water pump by inserting the hose on top of pump if any cracks you will clearly see the water escaping.
Remove an clean your poppet valve located on the throttle arm if equipped.
Keep us posted ..
 
Are you running the original thermostats? Since you mentioned the "SAND" word, have you ever taken the water jackets apart and changed the water deflectors? The lovely sand tends to cement inside of those parts.
 
I will have to inspect the pistons and workout what it is. Im pretty sure its a looper but i will check. I was told that after sitting for a while, the thermostats can seize up a bit and dont allow circulation when the engine gets hot (though if the engine is really that hot i should not hav been able to touch the cylinders...). I have pulled them out and will replace internals. So i am replacing the water pump impeller (and will also check for any cracks and leaks etc) and also the thermostat internals. I will keep you guys posted when i get her out in the water again. Thanks for all your help.
 
scare_crow_69 said:
I will have to inspect the pistons and workout what it is. Im pretty sure its a looper but i will check. I was told that after sitting for a while, the thermostats can seize up a bit and dont allow circulation when the engine gets hot (though if the engine is really that hot i should not hav been able to touch the cylinders...). I have pulled them out and will replace internals. So i am replacing the water pump impeller (and will also check for any cracks and leaks etc) and also the thermostat internals. I will keep you guys posted when i get her out in the water again. Thanks for all your help.
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I have the same problem and want to change the water pump impeller and the thermostat internals. Any recommendations where to buy them. I need someplace that can ship them to northern Canada too. Thanks in advance
 
You can get them from here, but customs and taxes are a killer into Canada. I know!! Better off trying a OMC dealer, even if in southern Canada, and have them ship the parts by Canada Post. Good Luck.
 
bill_w said:
You can get them from here, but customs and taxes are a killer into Canada. I know!! Better off trying a OMC dealer, even if in southern Canada, and have them ship the parts by Canada Post. Good Luck.
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Thanks Bill for getting back to me so quickly. I found a good pump kit from Mallory on iboats web site. The total cost including shipping, taxes and customs fee was under $100 so I hope I get them in a couple of weeks. Our boating "season" doesn't start for a few more weeks so I hope to have my motor ready by then. I'm going to try and change the water pump and housing to see if that fixes the problem but if it doesn't then I'll look at the thermostats. I know I have to check all the wire connections , especially the grounds, as I have no warning sounds at all. It used to work, like a short beep when I turned on the ignition, but lately there hasn't been anything. Thanks again and I'll post later this summer if the water pump replacement did the job.
 
The short beep is what I get on my 115 and 150. Try grounding out the wire from the sending unit on the block and see if that gets the horn going. Could be a wire problem, could be a horn problem. I ordered about $40 worth of stuff from here, time I got it into Ontario it was over $100, mostly GST and customs fees. Same things are available from any OMC dealer. I usually go with Sierra parts, same quality, cheaper price.
 
bill_w said:
The short beep is what I get on my 115 and 150. Try grounding out the wire from the sending unit on the block and see if that gets the horn going. Could be a wire problem, could be a horn problem. I ordered about $40 worth of stuff from here, time I got it into Ontario it was over $100, mostly GST and customs fees. Same things are available from any OMC dealer. I usually go with Sierra parts, same quality, cheaper price.
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Thanks, I'll try that. I'm guessing that it is just a corroded wire because my boat is permanently in salt water. I saw the Sierra kit, for about $15 less, but it didn't have all the rubber o-rings or replacement screws so I went with the Mallory kit.
Thanks for letting me know about the horn.
 
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