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70HP Johnson 2 smoke question

3K views 13 replies 6 participants last post by  sundrop 
#1 ·
Here of late my outboard has been playing stubborn to start. Thirty days ago she would start and be running in 15-20 seconds, today it's more like 5 minutes of trying and she'll start and run like a top.
Once it has started I never have an issue the rest of the day, she'll start the first time.

I pulled the cowl, had my wife push the key in (for choke) and I believe I see that the choke is working. I have replaced plugs and the fuel/water seperator filter. While playing around I noticed the dreaded "ethanol has destroyed the integrity of your fuel line" syndrome and replaced the fuel line from filter to outboard.

Does anyone have a suggestion of where to start the diagnoses? I'm assuming that it is carb cleaning but was hoping to hear from those more experienced with outboards.

Rick
 
#3 ·
Gene,
I went to local Johnson dealer to purchase plugs, what they sold me were NGK's, what I pulled out were NGK's so I assumed that to be ok. Also to clarify, it tries to start and run, runs for 2 seconds and stalls. This happens repeatedly then out of the blue she starts and purrs like a kitten.
Then starts like a champ after the first start for the rest of the day.
Fuel is brand new (added this morning) in to a 6 gallon tank, 2 smoke oil tank was filled last week (problem already existed)
 
#5 ·
From my understanding and my practices (im no way a expert) I never use the choke that's only when its cold out and the engine is cold, my understanding. My motor used to act same as yours take a few cranks to starts and then once started would turn over wonderfully the rest of the day. Now I crank mine for 2 secs. and she fires right up. Now to get to the point I did the same as you plugs cleaned carbs oil water 10 micron filter. Drained my carbs a few times and added seafoam to my gas.. now its fine. Another thing I start my motor if I don't use the boat weekly. And as with any battery they lose their charge SOMEWHAT in a month as you said. Mine is a 02 Yamaha 2 stroke 90hp All work done on by me and my friend Daniel a US coast Guard Motor Tech lol Shout out Daniel!!
 
#6 ·
You didn't say what year it is so assuming it is a non VRO carbureted engine, clean the carbs, make sure you pump up your bulb fully before you start it and that the bulb is good (I think you said you've replaced this so should be ok) If the issue continues your fuel pump diaphragm is getting weak, which is common with ethanol wear. Assuming you don't use a VRO, You can buy a kit to rebuild the pump on ebay for around $15 or a whole pump for around $50. New style carb kits are $16 ea but you will not need a new kit if you get your gaskets off cleanly and reuse them. I just bought a new pump, a pump kit to rebuild my old one as a spare, and 2 carb kits rated for ethanol for my 55hp Rude.
But before you do any of this try a whole can of Seafoam in about 4 gal of gas. Run it wide open on the water and occasionally hit the choke to bog it down and release. This forces a large quantity of cleaner through the various jets and venturis within the carb and will often clean them up since it does actually run as it is. Use the old plugs and afterwards change for new ones. I keep my old ones in my boat box for on the water repairs because occasionally you will foul one.
I buy off Ebay mostly from seller Wulffe Marine or online from Ebasicpower.com , I also use iboats.com from time to time. Saves a bundle.

**you also need to do a compression test, it might be getting low enough that when the motors cold it isn't getting enough compression to start until you have flooded the cylinders with fuel/oil mix. You can "rent" a compression tester from auto zone, advance, oreillys etc,
 
#8 ·
I wish all these guys with issues were closer, I could help ya out for some very modest pocket change and/or fishing trips :)
 
#10 ·
I don't know much about engines, but I do have a 90hp 1999 Johnson outboard that got sluggish on initial start for a while.

I had a gummed up carb that had to be cleaned last summer, and then this summer I had my starter die on me.

My engine turns over and starts like a champ now, and those are the only two things I can think of that might have made the difference. I suspect for me it was the starter, as I notice a much more vigorous 'crank-to-turnover' than I used to and it doesn't cough and stall like it used to upon first start.

Dunno if that's of any help at all.
 
#13 ·
Update

Other than adding a fuel system cleaning additive I have done nothing with the hard start issue I have been having for the last couple outings.
Saturday morning she started right up on second attempt and purred like a kitten the rest of the day.
I have never been one for believing in "miracle in a can" but this cleaning additive may have very well helped out (or I just got lucky)
 
#14 ·
I have saved many boat engines, lawnmowers and motorcycles a trip to the shop with a can of Seafoam mixed strong.
 
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