1990 Johnson 15hp rough starting and dying

[samo_ott]

OK, this motor is out of my scope. From those of you that have read my posts before I work on 50's and 60's (the easy access motors). But a neighbour who's a senior is having problaems and asked me to take a look at this motor. Model - J15RELESR Serial - C 8489056.

He has it on a small pontoon boat. Since last fall it has been dying on him and hard starting and occasionally leaving him stranded. Not good when you're in your 80's! This season he's gone thru 3 tanks and then it hit a no start condition the other day when they called me. There was spark so I sprayed some pre mix in the carb and it fired right up. So obviously a carb issue. But I look at that carb and I see no way to get it out. It's damn tight in there and no way to reach the nuts that hold it on. Can anyone shed some light on this issue for me please. Does the power head have to come off to do carb work? EEuuiieee... it looks like a nightmare to get it off. It's electric start also and it's all crammed in there. Can it be anything else other than the carb? Is there any new high tech things they did on the '90's models?

Also, my Seloc manual only goes to '89. Is the '90 the same or similar to the '89 model? Can I use the Seloc as a rough guide?

Any help will be appreciated. thx, Steve

 

[tashasdaddy]

Re: 1990 Johnson 15hp rough starting and dying

tapping on the side of the carb bowl, stuck float needle.. also mix up a strong batch of seafoam, like for decarb, maybe that will help.

 

[iwombat]

Re: 1990 Johnson 15hp rough starting and dying

You need to remove the airbox, choke lever, and starter assembly to pop the carb off. The airbox will need to go forward about 1/4" to clear a nipple from a recess in the carb body. The airbox takes a bit of turning to figure out how to slide it up and out.

Edit: Idle mixture knob has gotta come off, and no choke lever - primer system on this year.

 

[iwombat]

Re: 1990 Johnson 15hp rough starting and dying

Careful with that newfangled motor there.

You might actually like it. Then where would you be?

 

[samo_ott]

Re: 1990 Johnson 15hp rough starting and dying

Like it? Are you kidding? I dont like it already! Can't see diddly squat in there! My old 18's are way easier to work on. You can fix them with a butter knife practically!

So you're saying the carb can come off without removing a lot of crap? Then I can drop a carb kit on it? Are the kits similar to the old kits or is there newfangled crap in the new carbs?

 

[iwombat]

Re: 1990 Johnson 15hp rough starting and dying

Yep, remove that and you can remove the carb. New kits are similar to the old kits.

Be careful when you replace the automated jet scrubbing nanobots, they get grumpy when you don't set them in just so. I had one disassemble the carb from the inside once.

 

[tashasdaddy]

Re: 1990 Johnson 15hp rough starting and dying

take a look at it here: thats one nice thing about working on the newer ones. http://www.evinrude.com/en-US/Accessories/Literature/

 

[samo_ott]

Re: 1990 Johnson 15hp rough starting and dying

Automated jet scrubbing nanobots?

Dang their hides, I'll wipe em all out!

 

[samo_ott]

Re: 1990 Johnson 15hp rough starting and dying

What about the high speed jet? Will I need the screwdriver contraption to remove it? Does anyone have the plans for that again? (heck, never thought I'd need it)

 

[iwombat]

Re: 1990 Johnson 15hp rough starting and dying

You really don't. If memory serves, you'll find the high-speed jet in the nozzle well (item #2). I'll let you know for sure in a few days when I get the kit for my 8hp.

 

[samo_ott]

Re: 1990 Johnson 15hp rough starting and dying

thx, will wait for the info

 

[iwombat]

Re: 1990 Johnson 15hp rough starting and dying

In the _side_ of the nozzle well. It's all right there. No need to remove it or anything. Clean in place.

 

[samo_ott]

Re: 1990 Johnson 15hp rough starting and dying

That's the high speed jet??? Huh? Sure as hell doen't look like the old ones!

 

[iwombat]

Re: 1990 Johnson 15hp rough starting and dying

That jet will dump straight from the bottom of the bowl into the riser tube. So, it sure seems like that's the critter right there.

Side note: I've taken apart dozens of different carbs on all kinds of things and I've never seen anything like that nozzle well thingy.