1978 70hp Johnson wont run in the water

[jonesd]

I have a 1978 70hp Johnson that sat in a pasture for 7 years. It will idle fine and runs when put in gear as long as it is out of the water and has the water muffs (I don?t know what it?s called) on. When in the water it idles fine but when put in gear it dies. I have cleaned the gas tank replaced the fuel filter and the carbs look clean.

 

[tassie ben]

Re: 1978 70hp Johnson wont run in the water

a first thought..the problem could be that in one instance you are forcing water into the engine and the other you are relying on the engine sucking the water up??? sounds odd the fact the watercould be the issue and not the gear transfer though..any other ideas or symptoms?

 

[o/b tech]

Re: 1978 70hp Johnson wont run in the water

When you say the carbs look clean, did you pull them apart and clean them thoroughly. The floats also have to be level with the carb when it is turned upside down. Is the idle too low. It should idle between 650 and 750 in gear. also make sure that the throttle plates open at the same time.

 

[tashasdaddy]

Re: 1978 70hp Johnson wont run in the water

welcome to iboats. amazed it started, needs more tlc before you run it in the water, water pump, service, before the burn it up. sounds like the idle is low, if you took carb apart and did not clean and use a rebuild kit, you wasted your time.
read awakening a sleeping outboard, and carb cleaning here.
http://forums.iboats.com/forumdisplay.php?f=31

 

[jonesd]

Re: 1978 70hp Johnson wont run in the water

?a first thought..the problem could be that in one instance you are forcing water into the engine and the other you are relying on the engine sucking the water up??? sounds odd the fact the watercould be the issue and not the gear transfer though..any other ideas or symptoms??

After the second tine of takeing it to the lake and loading it back up 10 minutes later. I put it in a water trough with it full and the water muffs on and it still doesn?t run in gear.

?When you say the carbs look clean, did you pull them apart and clean them thoroughly. The floats also have to be level with the carb when it is turned upside down. Is the idle too low. It should idle between 650 and 750 in gear. also make sure that the throttle plates open at the same time.?

No I did not pull them apart and clean them because all the gas had been drained. The engine dies when the idle is set below 1000.

?welcome to iboats. amazed it started, needs more tlc before you run it in the water,water pump, service, before the burn it up. sounds like the idle is low, if you took carb apart and did not clean and use a rebuild kit, you wasted your time.
read awakening a sleeping outboard, and carb cleaning here.?

Yes I am also amazed it started all that I did was put gas in it and a new battery and fired it up.
Ok I think your right the bottom line is I wasted my time because I didn?t get a carb rebuild kit because it looked very clean I thought I could save time and money. Why the water pump? Water is sprayed out the tube near the top of the engine. Does that indicate the water pump is good?

 

[jardon]

Re: 1978 70hp Johnson wont run in the water

Had same problem with my 78 70hp johnson but mine sat for over 15yrs. Had carbs rebuilt which solved problem. Ran fine after that.

 

[mikesea]

Re: 1978 70hp Johnson wont run in the water

though the carbs were drained,it likely had some residual whithin the passages of the cabs,the passage ways are very small ,the tinyist of crud will give problems,as for impeller,it is a maintaince item,needs to be changed fairly often,like once a yr,you can gamble at more time,but the worst thing for an impeller is to sit.they take the shape of the sitting position and become less effective,brittle and can break off vanes or delaminate from their hub ,leaving you broke down,gear oil too a must