1982 Johnson 150 dies at WOT

[LDS2121]

I have a 1982 Johnson 150. I have been suspecting a blown head gasket, because of my manual. The plugs on one side of motor were clean and the other side were oily. Well I swapped sides with the plugs and now both sides are oily. ???? I have been getting a little white smoke at an idle . Sat we went skiing and ran a tank of gas no problem except engine seems to flood after quick shutdown . It will crank back up with poor idle unless I rev motor slightly. Sun went fishing and had gone about 1 to 2 miles at WOT and the motor just died,as if turned the key off. It had slight knocking sound as the RPM got lower. The engine cranked back up within 1 to 2 minutes and did it again after about ½ mile. I started it back up and went to boat ramp. Idled around and loaded. It ran good no noise the second time. Came home pulled head on left side and everything looks good, Gasket has small knick, nothing looks scarred. What can I do. This is my first boat, so I am not sure. My clymers manal does help much. I have rebuilt jeeps and trucks so I have tools and mechanical knowledge.

Thanks in advance
Larry

 

[F_R]

Re: 1982 Johnson 150 dies at WOT

Knocking sound as it slowed down??? That's serious. Are you sure it wasn't overheating? How about oil?

 

[AlanR]

Re: 1982 Johnson 150 dies at WOT

Do a compression test and tell us the results and we'll help you from there. Also tell us the model number so we could have more of chance to help you out.

 

[AlanR]

Re: 1982 Johnson 150 dies at WOT

You can rent a compression tester at like Napa auto parts or a place around there.

 

[LDS2121]

Re: 1982 Johnson 150 dies at WOT

The knocking sounded more like gears slowly grinding or engaging and not engine knock. I pretty sure that is was not overheating as I had that happen when grass got around foot. As for oil I use Johson evinrude oil as required. I will get the model numbers tonite. As far as compression check I'm not sure about that. I may have to send to mechanic as I don't have the tools for that. Is there a way that I can check it?
Thanks again
Larry

 

[AlanR]

Re: 1982 Johnson 150 dies at WOT

Also if you have a blown head gasket you'll be really down on compression and low on power.

 

[LDS2121]

Re: 1982 Johnson 150 dies at WOT

OK thanks , I will rent one on way home. I have pulled the left head adn will replace the head gasket before comp check.
I will let you know what it looks like.
Thanks again
Larry

 

[LDS2121]

Re: 1982 Johnson 150 dies at WOT

Ok I got more info
Model # J150TL CNM
SN J57000825
comp check
110 120
105 100
105 120
I pulled heads and all cylinders are smooth except for the 100 it has some scatches on it. All pugs are oily also

Thanks again
Larry

 

[LDS2121]

Re: 1982 Johnson 150 dies at WOT

i also put on two new head gaskets

 

[emdsapmgr]

Re: 1982 Johnson 150 dies at WOT

How does it run in the water with the new head gaskets?

 

[LDS2121]

Re: 1982 Johnson 150 dies at WOT

I have not put it back in water yet. I was going to see if I needed to check anything else before I run it again.