40hp Johnson wont engage

[dogpaddlin]

I have a 1970 40hp Johnson electromatic shift motor that does not want to go when I put it in gear. I know the prop is spinning when in the driveway, but when I get it in the water all it does is churn the water behind the boat, but wont push it. I have checked the shear pin and it is fine.

A little more background, the motor was originally on a 1970 model Tri Sonic that had a rotted transom. The motor had never given me any problems until I tried to swap it onto a 1971 Glastron. Both boats were 15ft long.

Is it possible that I just need to adjust the cable length? Could changing out the fluid help?

 

[Joe Reeves]

Re: 40hp Johnson wont engage

It sounds like you may have a short shaft engine on a long shaft transom, meaning that the propeller is not as low as it should be.

The cavitation pl;ate just above the propeller should be approximately 3/4" below the keel at the transom. Is it?

 

[dogpaddlin]

Re: 40hp Johnson wont engage

It is. The measurement was the same on my old boat.

 

[matt9923]

Re: 40hp Johnson wont engage

I am thinking lower gear case. Actually the cable make the cable tight as possible. This happened to me, my shift lever has an adjustment on it an did't was all the way forward so i made it all the way back and that gave the lever enough to keep it in gear. It would sit in gear in the driveway but in the water under power i would have to sit their holding the lever. Just make sure the cable is tight. After taking out the flips screw (don't touch it) i had to crack the lower unit and fix the shifter.
Not a hard fix or problem pissed me off being a mile away form home having to sit in the back holding it.
Matt Good luck