1970 60hp Johnson outboard

[metz]

The motor will run at idle good when I play with the throttle under the hood but when i drop it in forward and I go to full throttle it will only get up to 10-15 mph. I just got it fixed in michigan and I am in Cincinnati. It has been sitting for approx 28 yrs. The lower unit has been redone and the carbs were rebuilt last July. The gas is the same from last july but still smells good. Any ideas on what to check? Could the gas be the problem if it still runs at high rpm when at idle and I move throttle?

 

[JB]

Re: 1970 60hp Johnson outboard

Wrong forum Metz.<br /><br />Gone to Johnson Troubles.

 

[metz]

Re: 1970 60hp Johnson outboard

sorry, first time using this thing. What should I do to

 

[JB]

Re: 1970 60hp Johnson outboard

Pretty sure you are dropping a cylinder, Metz. What it does with no load cannot tell you that.<br /><br />When you throttle up, does the engine speed up but the boat not go, or does the engine not rev up?<br /><br />If the engine revs without making the boat go, check the prop for a spun hub.<br /><br />If the engine wont rev up under load: <br /><br />Disable the spark plugs, one at a time, with her at idle. If the rpm drops or the engine quits that cylinder is making power, if not that is a dead cylinder. <br /><br />Check to see that the plug wire will make a hot, blue spark to the block of at least 7/16". <br /><br />If you have a hot spark to a dead cylinder try spraying a bit of premix fuel (NOT starting fluid) into the carb of any dead cylinder. If the idle picks up that carb need attention. <br /><br />Good luck, and let us know what you find.

 

[metz]

Re: 1970 60hp Johnson outboard

Ok, I am obviously new and don't have too much of a clue. I will try what you said. Thanks for the reply. I will let you know. This is my first boat. It will run when I put the throttle down but it won't go over 10-15 mph. Maybe one of cylinders is not firing. <br />thank you