1983 Evinrude 35HP

[Fishing in driveway]

Good afternoon all. I have a 1983 Evinrude 35HP that’s overheating. It was sitting covered for 5-6 years. So far I’ve replaced the impeller, and thermostat. I’ve also unplugged the water discharge tube from the intake to make sure it wasn’t clogged. Overheat buzzer is coming on after about 1-2 minutes. I’m very mechanically inclines, but mainly work on large engines. I’m assuming something is clogging a water passage. Any help would be greatly appreciated. Thanks in advance

 

[racerone]

Are you test running in a bucket ?-----If so the water level in the bucket must be 6" ABOVE the pump.

 

[Fishing in driveway]

Thank you for your reply, I have muffs hooked up to the lower unit

 

[oldboat1]

If it were mine, I think I would remove the l.u., and see if I could run water up the tube using a hose. Use fuel line or similar to reduce the hose diameter, maybe using the male end of a quick disconnect. If circulation is proper, water should exit down the leg and out the exhaust port on the rear of the leg (if you have that), and out the tell tale.

 

[Fishing in driveway]

Thank you oldboat1, if water doesn’t discharge at that point, what would be the next step. After replacing the impeller, I would assume the water is moving up the copper tube. The impeller that I removed was identical to the one purchased with the exception of the keeper. The old one was a pin, and the new one was half mooned shaped, that appears to be the correct one, because of the cut out on the shaft.

 

[oldboat1]

Absent proper discharge, would suspect a blockage a water passage (would have taken the pump out of the equation).

On the pump, though, the parts list seems to call for a pin/dowel -- not saying that's an issue with your model, but might be a reason to check the impeller. With the l.u. removed, you should be able to feel and hear the impeller rotating if you turn the shaft by hand.

 

[jasper60103]

Thank you oldboat1, if water doesn’t discharge at that point, what would be the next step. After replacing the impeller, I would assume the water is moving up the copper tube. The impeller that I removed was identical to the one purchased with the exception of the keeper. The old one was a pin, and the new one was half mooned shaped, that appears to be the correct one, because of the cut out on the shaft.

Yes, I've seen new style pin in my water pump kits and it works. That said, did you buy the kit or just a new impeller and pin? A crimped water tube grommet is another common fail point. Anyway, I usually refer folks to this video that are having issues.

https://www.youtube.com/watch?v=xAJfBKNs7bo

 

[Crosbyman]

try pushing some pressured air backwards from the discharge pee hole to see if air flows down the water tube maybe it will push out any blockage

 

[jimmbo]

try pushing some pressured air backwards from the discharge pee hole to see if air flows down the water tube maybe it will push out any blockage

Blowing air in the pee hole will may clear the pee hole and hose, but since water exits the block in other locations, there is little chance of building up pressure to dislodge anything or much air exiting the water tube

To the OP
If the pump is working, the water tube attached and not leaking, there may be blockage in the cylinder head, or block. Removal of the head will allow inspection of the water jacket and water passages in cylinder head gasket. Removal of the jacket cover on the head will allow for inspection of that area

When you replaced the impeller, what condition was the rest rest of the pump in?

 

[Fishing in driveway]

Thank you all for your replies, I replaced the entire assembly, not just the impeller. The impeller was in bad shape, one of the fins fell off when I removed it, didn’t notice any scarring of the housing. Got ahold of the original owner and he had mentioned the motor was rebuilt some years back, and after the rebuild there was only 6 hours on it. I’m wondering if the mechanic did something wrong, and the original owner didn’t pay any attention to the tell tale. Might be a full rebuild at this moment. I will try to force water into the water intake tube, to see at least the tell tale will produce something. Once I figure this out, I will keep everyone posted. Thank all of you once again for your replies and advice.

 

[Fishing in driveway]

Also it’s worth mentioning that the copper intake tube came off while I pulled off the lower unit, I aligned it when installing the lower unit, as the copper tube was still attached to the impeller housing. Maybe there’s an O-ring that has detached. Should I install the copper tube first, then attatch it to the housing. I pulled the lower unit once again, and there was no water in the lower unit, so I’m assuming it aligned. Thank you all once again

 

[racerone]

Copper tube has to go in place first !!----Then the lower unit is installed.

 

[Fishing in driveway]

Thank you for the quick response, is there an O-ring that attached to the top? If there was an issue with the tube being misaligned, wouldn’t there be water in the lower unit crevasses? After running it for 1-2 minutes, I would assume water would be pouring out of the tube

 

[racerone]

Just install the tube.------Install the lower unit.------Test run.

 

[Fishing in driveway]

Okay it’s fixed. Replaced the new impeller with another new one, and it works now. Thanks for all the advice