Robert1997
New member
Hey this is my first thread, im sorry for my bad english I'll try to make it as clear as possible what my problems are.
So I bought this Johnson 15HP motor from a guy which said everything was in perfect condition (not gonna lie it looked like it was in good condition when he sent videos of it) so I brought it back home - immediately went to test it out and upon testing I had some troubles with cooling when I started the motor. It did not want to cool it self at all on low rpms, only when I put it in foward gear and started going fast then the water started "peeing" from the tell tale. First guess for me was the thermostat did not open at the start (but I wated there in neutral for a couple of minutes before putting it in gear..) I brought it to my garage for further inspection and I found out that the impeller was burnt to hell.. the blades were melted I have never seen that before so I ordered a new pump kit and installed it then I went to test it again and for some reason there was no water coming out at all (not even in gear).
So I brought it back again to my garage to do a second fix - I opened up the cylinder head plate and the water plate on the side of the motor to clean all the water passage ways - after I opened it I was shocked how much salt there was built up around the passage ways So I cleaned it very thoroughly almost to bare metal for more efficient cooling and closed the plates back up with my own made gaskets (I live on the other side of the planet so ordering new gaskets from USA takes a while for it to come..) well those gaskets that I made my self were great! The water was running at low RPMs as it should do, it was not hot and the stream was really good and I tested it on the water and it ran really good up until I decided to invite some friends on my boat and I put some load on the motor... with 4 people on board it was pushing water hard until it suddenly completely stopped...
I got back to my garage again for more fixes and I couldn't figure out what was wrong - but I decided to take a month off of fishing and I ordered new parts from the USA. When they arrived I re-installed everything they sent me (gaskets, grommets, thermostat, water pump kit) cleaned all the passage ways again, and now I am struggling even more than before... The telltale is weak at low rpms (very very weak) to the point where I can't keep my hand on the flow because it burns.. in gear it decides to stop completely especially in reverse which is super weird I tested it on a lake and no difference there either I will attach a video link for you to see how it works now, maybe you'll have some ideas on how should I continue with fixing it or should I just let go and move on with my life. https://youtu.be/RpmwxSVb0rY
So I bought this Johnson 15HP motor from a guy which said everything was in perfect condition (not gonna lie it looked like it was in good condition when he sent videos of it) so I brought it back home - immediately went to test it out and upon testing I had some troubles with cooling when I started the motor. It did not want to cool it self at all on low rpms, only when I put it in foward gear and started going fast then the water started "peeing" from the tell tale. First guess for me was the thermostat did not open at the start (but I wated there in neutral for a couple of minutes before putting it in gear..) I brought it to my garage for further inspection and I found out that the impeller was burnt to hell.. the blades were melted I have never seen that before so I ordered a new pump kit and installed it then I went to test it again and for some reason there was no water coming out at all (not even in gear).
So I brought it back again to my garage to do a second fix - I opened up the cylinder head plate and the water plate on the side of the motor to clean all the water passage ways - after I opened it I was shocked how much salt there was built up around the passage ways So I cleaned it very thoroughly almost to bare metal for more efficient cooling and closed the plates back up with my own made gaskets (I live on the other side of the planet so ordering new gaskets from USA takes a while for it to come..) well those gaskets that I made my self were great! The water was running at low RPMs as it should do, it was not hot and the stream was really good and I tested it on the water and it ran really good up until I decided to invite some friends on my boat and I put some load on the motor... with 4 people on board it was pushing water hard until it suddenly completely stopped...
I got back to my garage again for more fixes and I couldn't figure out what was wrong - but I decided to take a month off of fishing and I ordered new parts from the USA. When they arrived I re-installed everything they sent me (gaskets, grommets, thermostat, water pump kit) cleaned all the passage ways again, and now I am struggling even more than before... The telltale is weak at low rpms (very very weak) to the point where I can't keep my hand on the flow because it burns.. in gear it decides to stop completely especially in reverse which is super weird I tested it on a lake and no difference there either I will attach a video link for you to see how it works now, maybe you'll have some ideas on how should I continue with fixing it or should I just let go and move on with my life. https://youtu.be/RpmwxSVb0rY