Update on my 18 hp Johnson-More questions

I would first off like to thank everyone for there help so far. Second, I am trying to get a manual as we speak. Now for the "fun" part. I got another rope installed in the winder and its all back together. It took me a few (about 10) pulls to figure out where everything needed to be to fire it off but it runs again. I believe that I did in fact over heat it becuase this time I didn't see any water come from the pisser. I have noticed other topics refering to a thermostat. Does my 1961 18hp Johnson model FD-15 have a thermostat? How hard is it to change the water pump impeller? I am very mechaniclly inclined, I made my living fixing cars for a while so I am not scarred, I just know nothing about boat motors. Thanks guys.

Re: Update on my 18 hp Johnson-More questions

It has a thermostat and no pisser. <br /><br />It will emit a slight spray out of the exhaust bypass opening with the exhaust. The spray will increase somewhat as the motor warms after a few minutes.

Re: Update on my 18 hp Johnson-More questions

If it has no pisser then what is the 1/4 hole on the side about halfways down that sprays water? It does seem to do as you suggested also. Man I need that manual fast!

Re: Update on my 18 hp Johnson-More questions

The impeller is not usually too difficult to replace. Whether or not the engine has seen salt water use and how it has been stored during the off season can significantly impact how easily it will come apart. <br /><br />I had one lower unit in which the drive shaft had become frozen into the powerhead due to corrosion. It was a real bear to get apart but I finally succeded. Had another one where the screws holding the water pump housing to the casting broke off in the casting due to corrosion. Had to drill them out & re-tap their bores. <br /><br />I'm sure the pros on this board see this kind of stuff regularly and thanks to help from some of them I finally got my driveshaft out without breaking anything. I do enjoy mechanical work and have learned alot since I started working on my older engines but the driveshaft issue took me a week of soaking, wiggling, pushing & pulling to get it apart and there were a few times I considered chunking the engine over the fence.

Re: Update on my 18 hp Johnson-More questions

Kenneth<br /><br />Did you run motor on barrel??<br /><br />Few times I have seen the same.... no water even catation plate is well under water or maybe occasinally just a little spray of water. Try to add more water as water pump is located quite high above anti cavitation plate. It need's water level almost as high as exhaust relief to pump properly. I have same with my 64 18 hp Johnson last summer and pulled it apart just to find out that it was ok. Added water to drum and water circulated normally.<br /><br />Tumpaa

Re: Update on my 18 hp Johnson-More questions

Tumpaa- I have it on my boat right now. I did run it on a barrell and can remember it spraying water. I also remember it spraying water right after I put it on the boat. I don't see it spraying now though.

Re: Update on my 18 hp Johnson-More questions

Tumpaa- I told you wrong. Looking at the rear its on the LEFT hand side. I was also told it doesn't have a pisser, that it does spray out the exhuast so now I'm really confused

Re: Update on my 18 hp Johnson-More questions

To tell if your engine is pumping water, there will be a warm spray coming out the exhaust when the engine is warmed up. Also, the engine's cooling jackets will be warm to the touch, not extremely hot.<br /><br />There is no tell-tale pisser on that engine, as is expected on newer engines, but the water also exits from the lower unit.