Idle cut out

[Jack Stasney]

Hey guys bought a 1979 140 Johnson rebuild this spring. It has ran great all summer. Lately though after running it across the lake it will cut out when I'm idling it up to the dock and trying to trailer it. Doesn't seem to do this when I'm first cold starting as I usually let it idle to warm a little. One note: I did take the fuel filter off to make sure it was clear and it was good; however I did find that the rubber washer that seals the filter has a tear in it about half way through the outer ring of the washer. Worth replacing yes, but causing my problem? What do you think? Thanks for the help.

Also I wanted to mention that the spark plugs seem to be burning really well. I've been using them all summer without any issue. It is a two stroke, should I replace them anyways?

[marine_man]

What is the primer bulb like when it cuts out? Soft, or firm?

On the sparkplugs - if they're working good I'd continue to use them...

marine_man

[Jack Stasney]

I felt the bulb and it was soft, kind of spongy while it was running. This would be while I have the it idled up the little bar up. If I push this down it will stall out right away unless I through into gear and give it gas, so its hard to say exactly what the bulb is like right at the point of idle when I lock the idle bar in place. I am able to get it primed up to firm before I start it. To me it feels good and I did replace it this year. Also I replaced all of the gas hose as well, earlier this spring.

[marine_man]

So, this only happens when you engage the shallow water drive (tip the motor up)?

If so, it sounds like a fuel delivery issue - try hitting the choke the next time and see if it continues to run. I'm wondering if something isn't quite right with your carb bowl float, and when you tip it up it floods or staves the engine for gas

marine_man

[Jack Stasney]

Hey Marine man what do ya think of this suggestion? I just got off the phone with the guys that did the rebuild they said to take it out and while in the water try advancing the idle screw a bit after just throwing it in gear. Otherwise they told me to bring it in to their shop and they'd take care of it. Well it's good to know that they are backing it at least.

Also as to your comments above I did try hitting the choke as you suggested and it didn't seem to help. Again, pull the idle bar and your fine or go flying across the lake and your fine. Seems like if you get past the initial 1/4 trottle area then it'll go just fine too. I had backed it out over deeper water so I didn't try tipping the motor up either. By the time I got close enough in it quit and I just coasted it in to the trailer.

[marine_man]

Do you have a tach on your motor?

What does it idle at (for RPM) at Neutral and in Gear?

It should be 800 in Neutral and 600 in Idle

marine_man

[Jack Stasney]

Thats what they said as well. They felt I should test the "in gear" 800 RPM in water under load. What do you think? Can I do this in my driveway with the muffs on?

[marine_man]

When setting Idle speed you need to be in the water - the backpressure of the exhaust from the water is needed to correctly set the idle.

marine_man

[Jack Stasney]

Marine man upon further inspection one of the spark plugs looked like it had some of the the white insulator eat'n away from it. Something to worry about? Also I talked to a couple of my local auto techs while purchasing a couple of new sets of spark plugs. They compared prices and NGK's are waaaay cheaper than Champs. Whats your opinion? Also one guy felt that replacing them might cure my problem since two strokes are hard on plugs. I'm still planning on looking at the RPM's this weekend, how do you feel about this added evidence???

One more update the fuel screen/filter gasket that was cracked has been replaced.

[marine_man]

Well, that probably wasn't helping things... from my experiences I think Champions runs better than NGK's in Johnsons, but it can't hur to try them if they're that much cheaper.

With the fixes you've made I think you should be in pretty good shape...

marine_man

[boatfixer]

It's been my experience that champs work better in OMC'S and NGK's work better in Mercs.

[Jack Stasney]

That figures, I still have a set of champ's so I'll use them for now. I started it up in the driveway tonight and it's purr'n nice again! Planning on going out tomorrow so I'll report back on the RPM's

[Jack Stasney]

Well after messing around with the throttle screw a bit I really think the whole throttle assembly is out of whack or something. The screw itself bottoms out before it even touches anything, so I don't even think its doing its job, unless I'm just looking at the wrong thing but I looked it over and I'm fairly sure its the right screw. Anyways when I put it in idle it drops down from 1000-800-700-650-600 then stops, but like I said the whole thing really just seems loose and probably needs a good look over by someone who knows what its suppose to look like. Keep in mind I've had my RPM gauge disconnected for other reason for quite sometime now, but I also noted that since I disconnected the gauge my RPM's which were at 5600-5800 when at WOT are now at 4900-5000. Bottom line I need to take it in. Thanks for all your help guys. I would be interested in your comments on these latest findings.

[boatfixer]

Good luck with it Jax, be sure to let us know what they find. It almost sounds like its running on 3 cylinders. The screw that you were looking at could be the full throttle advance stop, is that possible? Either way, you're right, you may be better off taking it in.

[Jack Stasney]

Okay finally got a chance to take my boat in and here is the final verdict on this. Before I start I'd like to thank the guys at Wholesale Marine for standing behind there work. Technically my engine was out of warranty, but they understood the situation and are taking care of fixing it at no cost to me. So here is what happened... Looks like one of the thermostats didn't open up and fryed the two cylinders on that side, so it'll have to be taken in and have those cylinders bored out. Down side is that the walleyes got there feed bags on and it'll take a few weeks to get this all completed. Oh well it could be a whole lot worse. Again marine_man and boatfixer thanks for all the help.

[boatfixer]

I'm glad to hear they stand behind their work. Too bad it went down during some of the best walleye fishing. I hope you get it back in time to get in on some of it. Keep us informed.

[marine_man]

Sorry to hear about your downtime, but at least it's not going to cost you any money!

marine_man

[Jack Stasney]

Hey guys I've heard of people not putting thermostats in some older motors at all. Whats your feeling on this? It seems a lot of the newer motors squeal or will cut out if they get to hot from talking to people, but not this old of a motor. You just find out the hard way you need a rebuild! Any suggestion or after market fixes that might ease my mind?

[marine_man]

I'd put them back in to regulate the engine temperature.

marine_man