76 Johnson 9.9 hit stick running rough

Hey everyone I'm new to this site, so forgive me if it's an already posted topic, but this is my first boat just a small 12ft aluminum boat with a 1976 Johnson 9.9 that ran absolutely great until I was out in the CA Delta cruising along and bam the motor hits something, so I look over the boat and see a small stick not more than an inch and a half around and 2ft long. But after I hit that stick I put the motor in neutral and gave it a second and then proceeded along my way but I noticed the motor running rough. Didn't sound nice and tight like it had before and I was only getting maybe half the power as I was. Now I know these plugs foul pretty easy from experience but the motor was running pretty violent shaking and what not. I also noticed that just below the head of the motor there's a small hole maybe 1/2" or so just at the top of the column that goes down to the propeller, and I don't believe that's the water pump hole that sprits water out, but I noticed a good amount of water coming out of it, a lot more than normal. I don't know exactly what the hole I'm talking about does or is so kind of vague. But just looking for anyone who may have had this problem or really just some good info on what I should go about checking and doing myself. Could a blown seal make the motor run rough and violent? I'm a pretty handy guy and very mechanically inclined. Any information would be greatly appreciated cause I'm kind of drawing a blank as to what I can do myself before taking it to someone. It ran absolutely perfect before I hit that stock. Thanks for any info!!

Suggest you post the Model number and post some pics of the "hole" you are referring to.

Does the motor idle smoothly, or only run rough when in gear?

CMOS

The model is a 10R76H. I'll take some pics and post them of the hole I'm referring to when I get home in a couple hrs. It idles just as rough. Also seems like I need to keep On the throttle to keep it running when I let off and let the idle come down it starts to die out. The motor was shaking pretty good and I just noticed more water than normal coming out the back when I fired it up once I got home from the day the incident happened. Before the motor ran great it sounded nice and tight and would hit the power band and really move some water, after I hit the stick was getting hardly any power.

Hard to imagine that hitting a wood stick would mess it up, but I would remove the lower unit and inspect everything just to make sure nothing got moved out of whack in there.
This motor does not have a pee hole, so I suppose you are referring to the water pump exhaust hole in the back just under the power head? Having more water than before coming out of there wouldn't be a bad thing actually, just means the impeller is doing its job.
However, you should only see water come out after the motor reached its running temp, and not immediately on cold start. Do you?

Honestly I thought the same thing how could a small stick hurt the motor but I noticed the stick after it happened so thought maybe it knocked something around in the motor. Anyways I came home and figured I'd swap the plugs and at least check that off the list of potential reasons. The plugs were both pretty black, not wet but the motor had been sitting for a couple days. I put in 2 brand new plugs and the thing fired up no problem running great like it had before. So now I have the question of when running at about full throttle and suddenly foul a plug can that cause the motor to jolt cause you were running at such high RPM and one plug fouled so the cylinder still firing can't keep up with it so it's a sudden loss of rpm? You were definitely correct about the hole I was talking about, it is for the impeller I don't have a little pea hole on mine. Also I seem to be fouling plugs quite regularly and I'm pretty careful with the amount of oil I put in the mixture 2.6 oz to 1 gallon of gas but is there any other reason that can cause fouled plugs? I always keep an extra set in my tackle box and a wrench just in case. If both plugs were black the could the rough run have been caused by the remaining plug firing intermittently causing the motor to sound rough? I really appreciate the info I know I have a lot of questions but I'd rather deal with this issue on my own and learn from it rather than take it to a shop and have it fixed but learn nothing. Thanks !!!!

The motor has 2 new coils but one of the coils the spring up in the shoe of the spark plug wire when I pull it off the plug keeps twisting in the shoe so I have to take a small screw driver and flip it back up right so that it will go back onto the plug. Now it can't spin when on the plug seated properly but maybe I'll chuck the 40$ and get another new coil and wire cause I don't believe you can just replace the wire. Also there's a bunch of grease in the shoe of the wire not sure if this is a bad thing or not it's a really light grease. Just on the wire that has the issue with the spring in the shoe.

FRYLE said:

Also I seem to be fouling plugs quite regularly and I'm pretty careful with the amount of oil I put in the mixture 2.6 oz to 1 gallon of gas but is there any other reason that can cause fouled plugs? I always keep an extra set in my tackle box and a wrench just in case. If both plugs were black the could the rough run have been caused by the remaining plug firing intermittently causing the motor to sound rough? I really appreciate the info I know I have a lot of questions but I'd rather deal with this issue on my own and learn from it rather than take it to a shop and have it fixed but learn nothing. Thanks !!!!

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Yeah been there done that on the 76. I actually had the slow speed needle completely out of whack, by accident I had never bottomed the needle up against the seat before pulling it back 1.5 turn, (I thought I had but did not) and therefore was running way too rich. It was running very rough as you describe, almost as if running on one cylinder.
Finally the plugs fouled and it wouldn't start anymore
Looked at everything (carb, ignition) and nothing helped. Then I thought I'd change the plugs, and it ran like a top again.
Got the slow speed needle adjusted correctly this time, and it's been running perfect ever since.
As to the mix ratio, manual says 50:1 for these motors, but some folks go as lean as 100:1 with no problem. I guess 75:1 would be a safe bet.

Oh I didn't think of the needle on the carb. So is that the recommended amount of turns, all the way in and back out 1.5 times? I should check that on mine and I'll definitely ease off the oil fuel ratio and see if it helps keep these plugs from fouling. Seems as though there's a really delicate balance to get these motors not to foul the plugs but I'm glad it doesn't seem to be anything major wrong with my motor. Thing runs great when the plugs don't foul lol. Always keep a set of plugs in the tackle box to get me out of a pinch if needed out on the water. Thanks again for the info really appreciate it! You'll definitely see me popping back up on here asking questions!

Keep the fuel mix at 50:1 you will foul the plugs more often with alot of slow speed operation just take spare plugs and tools out with you do not change the fuel mix period.

Just to clarify on the mix ratio: I am NOT suggesting you should change anything, only mentioning that some run leaner without any issue.
As a matter of fact, at one point int time, OMC had sent a global memo, recommending 100:1 ratio after running through a lot of plug fouling issues, but later reversed back to the 50:1 to steer clear of any premature wear on power head due to some inaccurate dosage measurement by consumers. (Source: Leeroy's ramblings)

Extract from his article:

Back when OMC re-introduced their 50:1 ratio of oil, an old time marine mechanic was told by factory engineers that their motors would survive on 100:1 but they couldn't trust people to measure it accurately or control what kind or the amount of oil they used. So they reverted back to 50:1 ratio as a safe haven. The 100:1 was sufficient lubrication for most motors while running.​

Slow speed needle: It is the single most important adjustable setting on these motors to get them to run properly.
And yes, turn it in all the way until you bottom out, and back it out one and a half turn. Then from here you can fine tune the adjustment to where the motor is running the best (usually about 1/8 of a turn before it starts sputtering).

Oh I see so really just don't ever go over 50:1 but if you happen to go a little less on the oil it technically wouldn't hurt anything. I may just back off the oil just a little bit. Also would running a different plug, one with a slightly higher heat rating help? I gap the plugs at .030 should I shorten the gap to say .025-.026? I prefer the NGK plugs over champion. Also a dirt bike buddy of mine had suggested running yamalube as the oil instead of the stuff I'm getting from the auto parts store, he said it burns cleaner and could help. Any recommendation on the actual type of oil used? Again I really appreciate the information!!!!!

Not sure if you're familiar with the source I mentioned above when talking about oil ratio specs, but if you're not, I strongly recommend you take the time to read it.
It will answer many of your questions, if not all of them, (including the spark plugs one) with detailed historical info and pictures. A priceless piece of information for any of us, old OMC motor users:

http://www.leeroysramblings.com/Johnson 9.9_15.htm

Wholly smokes that's like the holy grail of information for these older Johnson 9.9's! Thank you big time! Thanks to the older gentlemen who assembled all that information as well!! Definitely gonna read the whole article to get a better idea of how to take of these motors and keep it in tip top shape! Information overload hahaha!

Yes, Leroy's Ramblings is a treasure trove of info on the 9.9/15HP engines. Also, member Joe Reeves knows these motors so well he could answer questions in his sleep. He helped me diagnose and correct a cooling issue that nearly drove me bonkers.

I run only Evinrude Premium Outboard Oil in my 1979 9.9 and have never had a single problem. I buy it at my local Wal-Mart for about $20/gallon.
https://www.walmart.com/ip/Evinrude-Johnson-2-Cycle-Marine-Oil/36008461

I run a 50:1 ratio with have no plug fouling issues and quite honestly there is almost NO smoke. That's an amazing feat for a pre-mix outboard but it really does have extremely low amounts of smoke.

KJ

OK, so lots of confusing information on this thread. If I didn't think it might lead you down the wrong path I would have left it alone. OK, first off. It is not the wrong fuel to oil that fouls spark plugs, it is the wrong fuel to air that fouls spark plugs. So, keep using 50:1 oil and don't use any less.

Now the carb rich/lean setting is very important to spark plugs. It is probably the most important thing to keep your plugs working, except using the right plugs to begin with. The 1.5 turns out is just the initial setting to get it to start. To set it properly you let the motor warm up and bring it to as slow of ide as you can, in neutral. Now turn in the rich/lean screw 1/8 turn clockwise. Let the motor respond for 10 seconds. If the RPMs increase, lower them again with the throttle. Now turn in the screw another 1/8th of a turn. Keep doing this this until the motor coughs, spits and wants to stall or does stall. Now turn the screw 1/4 turn counter-clockwise, reposition the knob so that it points straight down, in the middle of rich and lean, and never touch it again.

As for spark plugs. The best plugs for that motor are NGK B6HS. You will not find a spark plug that will last as long as that one ON THAT MOTOR. That being said, if you do a lot of trolling, get a new motor. That model of motor wants to run hard. If you troll with it, expect to change your plugs every 4 hours of trolling...unless you like rowing. If you do troll for a while, make sure you open it up to WOT before you bring it back to land.