'76 johnson 35 hp exhaust leak worth fixing?

[tt600]

I have a 35hp johnson that runs strong....with the hood off. It is leaking exhaust and water under the carb where the powerhead meets the frame.
It also has become quite difficult to shift. I can live with the shifting problem by leaving it in forward. Running with the hood off is too loud, though. Is this a difficult repair and doable by me? I assume the cost for a gasket is minimal. The labor is my question.

 

[AlTn]

Re: '76 johnson 35 hp exhaust leak worth fixing?

freshwater or saltwater engine?

 

[tt600]

Re: '76 johnson 35 hp exhaust leak worth fixing?

freshwater or saltwater engine?

fresh only. Some slight rust on the flywheel. Looks pretty good otherwise. I have a 90s 30hp and this is a bit more powerful so I have been using it.

 

[AlTn]

Re: '76 johnson 35 hp exhaust leak worth fixing?

doable...sure...looks like no special tooling needed....weightwise you may be getting into an area where it's safer to first remove the lower unit so you can insert the driveshaft/lower unit back up into the powerhead, rather than aligning the powerhead with the d/s when you drop the powerhead back in. I've recently done a '72 25 hp. and 18 hp. but they don't weigh as much. Other than that concern, it's the main fuel line to be disconnected, the vertical shaft disconnected, and the shift linkage/lockout lever. If you have electric start, whatever connects to the starter will have to be disconnected. From a weight standpont it'd remove the starter and bracket together as a unit.Then it's just a matter of removing the screws that attach the powerhead to the exhaust housing and it's ready to be lifted off.

 

[Don Hansen]

Re: '76 johnson 35 hp exhaust leak worth fixing?

As far as the hard shifting goes have you greased the shift handle? If you look there's a grease fitting in that pocket low on the handle.

DLH

 

[kodibass]

Re: '76 johnson 35 hp exhaust leak worth fixing?

Just take your time, take a few photos/video as you go along. Freshwater motor that runs strong sounds very worth a few bucks & a bit of your time to me.

 

[tt600]

Re: '76 johnson 35 hp exhaust leak worth fixing?

Well, I decided to try the cheap ($2) way and used some JB epoxy paste on the leak area. It stopped the leak when I ran the motor in my driveway. Next week I will take it to the lake and see if it works long term.

 

[tt600]

Re: '76 johnson 35 hp exhaust leak worth fixing?

last update.

took the boat to the lake. the motor still leaked exhaust but not bad enough to affect power with the hood on. Burned about 18 gallons of gas through it but then sucked a plastic bag onto the water intake and seized the head before I noticed. So it's headed for the scrap heap. It had a good run for a '76. Now I will put on my '93 30 hp. Hopefully I can get it to run as fast. The '76 always seemed to rev about 500 rpm faster.

 

[kodibass]

Re: '76 johnson 35 hp exhaust leak worth fixing?

bummer!

 

[Chinewalker]

Re: '76 johnson 35 hp exhaust leak worth fixing?

Same props? The '93 is actually about the same power as the '76 do to rating changes done in the 1980s. If they're not propped the same, that might account for the 500 RPM difference...

 

[tt600]

Re: '76 johnson 35 hp exhaust leak worth fixing?

Same props. I am going to compare jet sizes. I believe both are stock but could be wrong.

 

[tt600]

Re: '76 johnson 35 hp exhaust leak worth fixing?

I examined the jet sizes and found that the '76 35 hp had a smaller jet. A one sixteenth bit would not pass through. The '93 30 hp had a larger jet and the one sixteenth easily passed through. I changed jets and will go try this out next week at elevation 7600'. The carbs also look interchangeable so if this does not work I will do the swap.
When I last compared these motors it was at elevation 800' so perhaps a fair comparison will be difficult.