Sticky!

1975 evinrude 9.9. Got it running okay, worked out a few little kinks in it but still adjusting the carb because it'll only run for 10 sec to a min. My question is though, when turning the flywheel by hand, in a certain spot the flywheel gets kinda stuck and I have to force it threw that spot. Its not really hard to do so, but I have to apply more pressure to get it through that one spot. If I spin the fkywheel fast by hand it moves freely, and there is no sticky spot. Only when turn slow, and both go for with the spark plugs and without the spark plugs. I just replaced the entire powerhead because the old one had a broken crankshaft (some of you might have started to get annoyed at all the questions I've asked about it lol). The used powerhead, when I got it, spun freely and had good compression. It also spun freely at first when I first installed it, but yesterday when messing with it I was turning the flywheel by hand and noticed that sticky spot. Any ideas? The motor still starts up and runs so I'm hoping maybe its just carbon buildup I need to clean out? Dreading the fact that it might be a bearing, but that's just a guess. I appreciate all the help fellas!

Re: Sticky!

Let me know if y'all understand that, if not ill explain it a little better!

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suggest removing the l/u to take possible driveshaft alignment, l/u bearing, gear, out of the equation for this "sticky" spot

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I can do that this weekend. What should I be looking for? Didn't even think about the lower unit, but now that u said that is there any other way to test the l/u without removing it? And the engine is in nuetral when I hit this sticky spot, so wouldn't the drive shaft/lower unit not even be engaged thus dismissing that as the problem? Or am I not thinking correctly

Re: Sticky!

Everything in the lowerunit, except the prop shaft, is always turning if the motor is turning. Not really anyway to check without pulling it. Are you sure you are not feeling the piston compressing the air in the crankcase, that will make a feeling kinda like it is dragging as you turn it.

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Ahhh I see. Didn't realize everything is always turning except the prop. No, I mean I know what the compression feels like and it "sticks" even with the spark plugs out. I guess first step is taking off that lower unit. I did change the lower unit oil when I got it, used 80w 90 if I remember correctly. I filled it until the oil came out of the top hole but it seemed like it only took about half a liter or so. Does that sound right?

Re: Sticky!

A half a liter sounds about right for that motor. The compression I was refering to is below the pistons, in the crankcase. As the pistons in 2stroke motor travel down they compress the air-fuel mix in the crankcase until the piston uncovers the intake port. It is called building charge pressure, may or may not be what you are feeling.

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I don't believe that is it. Good idea but it feels like it is almost hitting something. It'll spin freely until that one spot and it just stops, then ill apply more pressure the flywheel and it will kinda jolt past that point as if something was stuck. The piston isn't hitting the spark plug. So maybe it is in the lower unit. Like I said it only does it when spinning the flywheel slowly, it spins freely when spun fast. The motor will still start up and run also, can't remember if I mentioned that or not. I guess it wouldn't be a good idea to run it, even though it doesn't "stick" when spun fast though huh?

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If it is that much of a tough spot, it sure wouldn't be good to run it and have the problem come out though the block. But with your more in depth discription, I wonder if it is carbon between the piston and head. Do you know if the problem is when one of the pistons is at TDC?

Re: Sticky!

I was going to mention that and completely forgot. It is when the bottom cylinder is at TDC. Every time it comes up to TDC is where it sticks. It feels as if the piston is hitting the head but it isn't. And the reason I know that is because it isn't hitting the spark plug. I bought a can of seafoam lastnight and ill run it threw it today. Hopefully that is what it is?

Re: Sticky!

The piston could have a chunk of carbon on it, or it could be on the head. Either way, it could be hitting the head and not the plug, tolerances are pretty close on these engines. Might try putting a bit of sea foam into the plug hole on the bottom cylinder with the piston almost all the way up and let it sit for a bit to soften the carbon up.

Re: Sticky!

Ill give that a shot when I get home. Best case scenario seems like it would just be carbon. Reading your last post, worse case scenario if its not a chunk of carbon and the piston is in fact just hitting the head, what would cause that? I guess there is a lot of different things

Re: Sticky!

The piston acually hitting the head while you are slowly turning it over is unlikely, there has to be something on top of the piston. Could be carbon (best case), could be part of the piston-rings on top of the piston (worst case). I doubt that a bearing has a sticky spot right at TDC. I've had motors fouled by carbon and striking the head, also had a piece of the top compression ring on top of a piston hiting the head too. If it runs good, and has decent compression numbers, my first thought is carbon.

Re: Sticky!

Sprayed some seafoam in the cylinder, let it sit for a while. Came back and it was less sticky in that spot. So I put the rest of the almost full can of seafoam in about a gallon of gas, actually got the motor to idle really well, ran the gallon through the motor, AND ITS NOT STICKING ANYMORE!!!! With my luck, I was for sure it couldn't be that easy. I thought i'd have the whole motor torn apart again before I was able to figure it out. A little decarbing is all it needed though. I really appreciate your help man. All your insight will help me in the future. Appreciate at it!

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Glad it turned out good! Now would be a good time to drop the lower unit, and replace the impeller if you haven't already, would hate to cook your good motor.

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simple is always great news....and agree with Guy

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bcjjones said:

Sprayed some seafoam in the cylinder, let it sit for a while. Came back and it was less sticky in that spot. So I put the rest of the almost full can of seafoam in about a gallon of gas, actually got the motor to idle really well, ran the gallon through the motor, AND ITS NOT STICKING ANYMORE!!!! With my luck, I was for sure it couldn't be that easy. I thought i'd have the whole motor torn apart again before I was able to figure it out. A little decarbing is all it needed though. I really appreciate your help man. All your insight will help me in the future. Appreciate at it!

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Seafoam is the best $10 you could ever spend on a motor. It's amazing. It's like the duct tape of outboards. It fixes everything LOL! Glad you got her running again! Happy Boating!