Oil INjection /40 HP Johnson

[T-290]

I have just been informed that my 40 horse Johnson is a 1991, My question is this,(#1)It is equiped with an oil injection system that seems to work fine! Was this a factory installed product or an aftermarket?I asked the seller if there might be a shut off systerm or alarm when you run low or out of oil. There is no guage or dial. Might the motor have some form of sensor on it? How reliable would this oil pump be or would it be a good idea to disconnect the whole shooting match and go back to pre-mixing the fuel?(#2)I have been informed that there is some seepage in the lower unit I have just drained it last nightfor the first time,I did not see the famed chocolate milkshake but just a slight trace of thickened oil slightly off color. Obviously there is water coming from somwhere that should not be there,Where do you start and how much damage would you assume has been done? After looking at the lower unit it appears by the paint that it has never been off before! Welcome to the world of boats. Huh!

 

[JB]

Re: Oil INjection /40 HP Johnson

Howdy, T290. Oil injection was standard on your '91, and is pretty reliable. You must visually check the tank regularly. You have alarm horn signals if oil is low or if the pump stops mixing. I don't like that. Like you, I would want a guage to keep me informed of oil level. The only oil injection engine I ever had was a mid-80s OMC 70. I disconnected it and used premix.<br /><br />Sounds like your lower end has 2 common problems: Monofilament damaged seal on propshaft and the original

water pump impeller!! Both speak of neglect in the past. Change the impeller promptly.<br /><br />Good luck.<br />Red sky at night. . . . <br />JB

 

[mthomasff]

Re: Oil INjection /40 HP Johnson

I have a 1994 Johnson 40hp with oil injection. I too worry about running low on oil. I just changed the oil in my lower unit also. It was dark and burnt smelling. I also noticed fine metal shavings on the plug magnet.

 

[T-290]

Re: Oil INjection /40 HP Johnson

Thanks J.B. for the response and advice! The seal on the prop shaft is this somthing that a Mechanic needs to do with special tools, or or is this common maintenence that can be achieved by somewone with mechanical knowledge ? And how about the Impeller for the water pump? From what I visually see, the stream of water coming out from engine seems quite strong even at idle. However I have no idea how old it may be! Could be the original, can't tell. I thought that they worked or they did'nt! Should this than be changed on a regular basis? years/hours of operation ?

 

[JB]

Re: Oil INjection /40 HP Johnson

Yo, T290. I would have a shop change my seals. The impeller is a little tedious and intimidating the first time you change it. After that, it's a snap. While it's at the shop, get them to show you how.<br /><br />The rubber impeller is a disposable. It can fail catastrophically, but usually just stiffens and comes apart bit by bit. The symptoms sneak up on you. From what you tell me, yours seems to be working okay. Change it anyway.<br /><br />Impellers should be replaced about once a season, and carry a spare aboard along with your spare prop and plugs.<br /><br />Red sky. . . . <br />JB