Bo’sun
Cadet
- Joined
- Sep 9, 2023
- Messages
- 22
Hello everyone! New here, first thread post. Here is the motor in question, 1965 Johnson 75 HP Super Sea Horse, model V4AL-17S:
I'd like to add a telltale or "pee hole", just for peace of mind that the impeller is pumping water. I've been doing some research and have found that people sometimes drill and tap into the water jacket on the head. I'm perfectly fine with doing that in terms of skill set, but I haven't been able to determine an appropriate hole location on port and starboard heads after studying pictures of the heads on eBay. Also, my engine is in pretty nice condition and was well-cared for by my dad until he passed it to me in the 1990s. I have cared for it the way he taught me as well, and at this point it's pretty cool to have such an unmolested old engine still running. So, if I can avoid drilling and tapping into such an original engine, I'm good with that approach as well, and would actually prefer it.
I found a "mystery plug" on the forward side of the upper starboard cylinder bank, #1. It's a large slotted screw with either a washer or gasket under it. This plug is not mentioned in the 1965 parts catalog as a part # that could be ordered, but you can see the hole on the cylinder block in the exploded parts diagram.
I ran across an old thread on this forum from 2007 where someone wanted to add a telltale to a 1975 85 HP. Apparently by that year there was no plug, but there was still a vestigial remnant of the port location on the casting. Someone mentioned that it may have been used for a water line to an automatic choke in bygone years, however none of the links or pictures are still working, so I could not see what they were talking about. In my model, the automatic choke used a tube carry hot air from the exhaust manifold instead of hot water from the block. But, 1965 is pretty close to the early years of the V4, so maybe it is the old hot water choke port?
The reason I haven't just removed it to find out, is that it is really stuck. My Milwaukee M12 FUEL impact driver could not budge it on the highest setting. If I'm going to remove it, stronger measures will need to be taken, so before I do that I just want to confirm I'm going down the right road. Here are some photos of the port in question.
My plan for the telltale outlet is to use one of these threaded holes in the lower cover that just have white plastic plugs in them from the factory. Again, the minimal / no modification approach. I wonder what they are for? Nothing attached in the parts manual, so perhaps another vestige of past model years.
I'd like to add a telltale or "pee hole", just for peace of mind that the impeller is pumping water. I've been doing some research and have found that people sometimes drill and tap into the water jacket on the head. I'm perfectly fine with doing that in terms of skill set, but I haven't been able to determine an appropriate hole location on port and starboard heads after studying pictures of the heads on eBay. Also, my engine is in pretty nice condition and was well-cared for by my dad until he passed it to me in the 1990s. I have cared for it the way he taught me as well, and at this point it's pretty cool to have such an unmolested old engine still running. So, if I can avoid drilling and tapping into such an original engine, I'm good with that approach as well, and would actually prefer it.
I found a "mystery plug" on the forward side of the upper starboard cylinder bank, #1. It's a large slotted screw with either a washer or gasket under it. This plug is not mentioned in the 1965 parts catalog as a part # that could be ordered, but you can see the hole on the cylinder block in the exploded parts diagram.
I ran across an old thread on this forum from 2007 where someone wanted to add a telltale to a 1975 85 HP. Apparently by that year there was no plug, but there was still a vestigial remnant of the port location on the casting. Someone mentioned that it may have been used for a water line to an automatic choke in bygone years, however none of the links or pictures are still working, so I could not see what they were talking about. In my model, the automatic choke used a tube carry hot air from the exhaust manifold instead of hot water from the block. But, 1965 is pretty close to the early years of the V4, so maybe it is the old hot water choke port?
The reason I haven't just removed it to find out, is that it is really stuck. My Milwaukee M12 FUEL impact driver could not budge it on the highest setting. If I'm going to remove it, stronger measures will need to be taken, so before I do that I just want to confirm I'm going down the right road. Here are some photos of the port in question.
My plan for the telltale outlet is to use one of these threaded holes in the lower cover that just have white plastic plugs in them from the factory. Again, the minimal / no modification approach. I wonder what they are for? Nothing attached in the parts manual, so perhaps another vestige of past model years.
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