Topic: 115 Evinrude Over Heat – Antique Outboard Motor Club,Inc

This topic has 14 replies, 9 voices, and was last updated 8 years ago by Mumbles.

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April 22, 2016 at 8:15 pm #4107
Mumbles
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A friends 1975 115 started to get hot near the end of last ski season and we are starting to wonder why. It had a new pump kit installed a few months before and it checks out OK but she did manage to pull some pieces out of the idle relief. They seem to be plastic and are quite hard. At first I thought a relief valve, 47 and 54, might have disintegrated but now I’m wondering if they couldn’t be from one of the deflectors/diverters in the water jacket and plugging up a water passage? I’m not sure what the deflectors are made of but there can’t be too much plastic in the system. Any ideas?

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April 22, 2016 at 8:40 pm #35252
dan-in-tn
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We made water deflectors out of duel line fuel hose. 1 1/4" long (separated) of course. It is the perfect size to fit tight in the water jacket. If the motor has been overheated or just time makes them deform & get loose. Sold thousands of them over the course of the 5 yrs. I was there.

Dan in TN
April 22, 2016 at 8:52 pm #35254
Mumbles
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Do you know what the originals were made of Dan? These pieces look as if they could have been fuel line size at one time. There seems to be a curve shape on one of them. Also, if you were replacing them often, did the originals deteriorate or just shrivel up?
April 22, 2016 at 9:03 pm #35256
dan-in-tn
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They do deteriorate, but not sure what you have there is them? I’m with you in that what you have looks too hard to be rubber hose. (Hard for me to tell consistency from a photo.) I would have said hard plastic, but don’t know where that would have come from unless it was a poppet valve? Looks like impeller blades, but you would know that. Maybe just carbon, but still had to come from somewhere? I do know if you don’t get it all out it will end up in the darnest places and cause further overheats. Not fun to go looking for all of the impeller pieces in a V-4/V-6!

Dan in TN
April 22, 2016 at 9:18 pm #35257
frankr
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The deflectors were indeed just hose.
April 22, 2016 at 9:50 pm #35262
pappy
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The new deflectors are solid instead of a hose.
At any rate, at this time, the heads will have to come off and the deflectors replaced. When a cross-flow overheats that is pretty much standard practice. Plan on freshening up everything in the thermostat area as well.
April 22, 2016 at 10:03 pm #35265
eviltwin
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Could it be chunks of impeller housing that has met a small rock?
April 22, 2016 at 11:46 pm #35272
billw
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US Member - 2 Years
It sure LOOKS like chunks of carbon. Could they have broken off shapes on the hot side of the inner exhaust cover, due to being cooked more than usual by the overheat event? If they were parts from bad valves in the thermo housing, my guess is that the pieces would have more signs of curvature and appear less angular?

Long live American manufacturing!
April 23, 2016 at 12:37 am #35274
fleetwin
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US Member - 2 Years
OK, well this is an interesting mystery. You mention the owner pulled these chunks out of the two idle/exhaust relief holes near the top of the exhaust housing, correct? Those pieces sure don’t seem like deflector fragments, but who knows. The other thing that puzzles me is that how those chunks got through the thermostat/ relief valve. I can’t think of anything after the thermostat/relief valve that is plastic. Are you sure those aren’t impeller chunks? How long has your friend owned this engine? Any previous overheats, water pump failures/replacements? It also seems strange that those fragments would just sit in those relief holes without being blown out of there. I think Bill raises a good point, it is possible that these chunks came out of the exhaust, the question is how did exhaust chunks work their way back up to the relief holes. I guess I would start by pulling the gearcase to see if any more chunks are trapped in the exhaust cavity, then pull the thermostat and heads.
Interesting project indeed, could be a real can o worms though. Let us know what you find!
April 23, 2016 at 3:54 am #35288
Mumbles
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quote fleetwin:

could be a real can o worms though.

You are right and I don’t really feel like opening this one up right now.

‘Remove the Tstat housing’ Sure, the bolts are so corroded I can’t even get a six point to grab them. The only other method is to break it off and discover the housing is NLA. I’m not touching anything until the parts are in my hand. Also, what happens if everything under the housing is OK? Back to square one and consider removing the powerhead or just the heads to look for blockage?

‘Remove the heads’. That would be simple if the bolts weren’t 40+ years old and corroded in place. Having all the necessary gaskets on hand would make my day easier to. I’m thinking I’ll just pass on this project and let the owner deal with it.
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