74 Johnson 70HP has water in cylinder

[swisscheeze]

The motor seems to be running fine (starts right up, idles great, 5500rpms,....), then all of a sudden it looses almost all power. It seems to still be running on all three, but it just doesn't have the power (max rpms = 2000). Even if I put it in neutral and pull the warm start lever, the most I can get is approx. 2000rpms. Starts are almost impossible and when I pull the plug on the lower piston and turn the key, water shoots out. I guess the question here is why does the motor only act-up after awhile and is it the head gasket or more?

 

[alcan]

Re: 74 Johnson 70HP has water in cylinder

Hi swisscheese<br />I guess the head gasket is as good a place as any to start. You will have to remove the head and have a look. Check head for warp.

 

[swisscheeze]

Re: 74 Johnson 70HP has water in cylinder

Alcan,<br />I am waiting for my service manual, Is there a lot involved when removing the head?<br />Will it be difficult to find replacement gaskets...?

 

[alcan]

Re: 74 Johnson 70HP has water in cylinder

Hi Swiss<br />It is not a difficult job to remove the head. Just be carefull not to snap off the head bolts.<br />I have never been to Europe so I don't know about parts there. I don't think it should be a problem though. (head gasket). Hopefully this will be a quick & easy, in and out repair.

 

[alcan]

Re: 74 Johnson 70HP has water in cylinder

Hi swiss<br />Another area to be concerned with is the exhuast cover plates and their gaskets. This is the large cover located on the port side of the motor. Same idea, be carefull with the screws. I almost allways snap one off.