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Intermittent stream...does this thing have a prostate? Mercury 110 question

B

Bullie

Regular Contributor
I picked up a Mercury 110 9.8 HP I think it is a 1978 a couple months back. It had a bad switchbox and lots of the insulation on the wires was cracked and falling off. I also cleaned the carb and put in a kit and got it running well. I replaced the water pump impeller as the stream was sporadic. After replacement the stream still wasn't steady. I have taken the LU off several times now and inspected the pump and copper input tube. I replaced the plastic outlet sleeve as it was a bit flared but the intermittent stream persists. I used the water hose to push water through and it comes out in a steady stream. I also blew it out from both directions with my air compressor. Still the same broken stream. When I had the LU off I clamped it in my drill and submerged the pump in my barrel and it pumped a good stream of water out of the sleeve. I am at a loss. The temp hovers at around 140 degrees after warmup at idle. Any ideas?

http://vid230.photobucket.com/albums/ee260/Bulliedawg2/Outboard/20150617_084145_zpsfc8evbgx.mp4
 
I honestly do not know the answer to your question. I have been checking the parts diagrams and have not found one yet. I would think it should have one but it's location isn't obvious to me like the Evinrude/Johnson motors I usually work on. I will continue to look for an answer to the question.
 
140 ' isn't too hot. If you are running that in a tight barrel, the exhaust will interrupt the flow of water coming in.

Jeff
 
racerone, I do not believe this model has a thermostat. I cannot find one on the engine or in any of the schematics.

I may be a bit too cautious but I have have another of these that has a steady stream in the barrel. This motor is staying around 140 and water is definitely circulating. I could not find a restriction in the lower end and water flows through the top in a steady stream from my water hose. So, like you guys have said, it may just be picking up air from the intake which causes the erratic stream in the barrel. The pickup location does seem to be in an area more likely to suck in air than some other designs.
 
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