70 hp Johnson trouble

[53150]

Hi my name is Will Vaughan I'm from Mississippi, new to the board. my 70 hp johnson serial#J5298763, mdl# J70EL65A starts ok and will rev up some with the warm up lever, but when I put it in gear it just want open up. when I take the hood off the engine it will rev up a little more but not like it should, and a little bit of gas will run out of the front of the carbs. when trying too start it. I'm a fairly advanced auto mechanic hobbist, but new to outboard repair any help will be greatly appriciated.<br /><br /> Will Vaughan

 

[53150]

Re: 70 hp Johnson trouble

after a little closer inspection I see that the top 2 carbs. have what i assume is the mainjet needle ( in the middle of the carb opening at the front) and the bottom one doesn't.

 

[alcan]

Re: 70 hp Johnson trouble

Hi Will<br /> Recheck the model#. I can't seem to find this guy.

 

[53150]

Re: 70 hp Johnson trouble

mdl# J70ELCSA.

 

[DJ]

Re: 70 hp Johnson trouble

Will,<br /><br />More than likely, your carbs. are gummed up and need a rebuild.<br /><br />It's not that hard, just a little tedious.<br /><br />I would recommend getting a manual (bottom left of iboats title page) so that you can do the synch. and link correctly, once done.

 

[53150]

Re: 70 hp Johnson trouble

I took the carbs off today and cleaned them out good. Had some trash in the needle and seat area. The motor runs great with the hood off, the boat jumps right up on plane, but with the hood on it will not even come close to planing out. any advise would sure be appreciated.

 

[outboardjake]

Re: 70 hp Johnson trouble

Either the air intake under the lower pan is clogged or there is an exhaust leak under the hood.

 

[alcan]

Re: 70 hp Johnson trouble

Hi Will<br />As Jake states check for exhaust leak. Mix up a short batch of fuel for testing, for the test batch double the oil to 24:1. This will give you a little more smoke to look at. The other area to look at is the electrical. Quite often you can get shorts jumping to latches and such. also check to see that the sound blanket inside the bonnet is glued in tight, and is not getting sucked up, (blocking air flow).

 

[53150]

Re: 70 hp Johnson trouble

Thanks for the help guys. Will give this a try and see what happens.