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9.9 1974 Johnson Heavy Black On Plug

patiolatern said:
Ok here we go:
The roller for the link and sync seemed to be in the correct position maybe a hair late in moving the roller.
Since I had the recoiler off I took the carb off and gave it a cleaning. The idle jet was at 1 1/4 turns out. Nothing found in carb. During cleaning.
Assembled it back to the motor and butterfly plates seemed to work properly as best I can tell. The internal plate(not choke) is working since I was able to put a zip tie in to feel it activate.
Put the roller for link and sync was put into the exact position required.
Assembled the recoiler and put the flywheel back on. Points were checked and were correct at .020”.
To start the engine I had to lean the idle mix by a 1/4 turn. Engine started and let it warm up watching thermostat open etc
After warming up the engine had pep and seemed to run ok. Was able to adjust the lean/rich to get all or most sneezes out of it at idle.
Ran engine in gear at medium speed and everything seemed to ok. Temp scans showed 145 f or so and after a while this climbed to 155 -160 then when I slowed down the temp dropped back to 145 or so. Water jacket on back end stayed around 110-120f.
Drop test was performed and engine continued to run after each spark plug was disconnected.

Ran for a fair amount of time and had idle down to around 750-800rpm in idle with limited sneezes so this seemed ok
Then I put it in gear and things seemed ok at lower rpm but then I started to accelerate and there was a lag as slowly the rpm’s came up to speed (with some excess smoke) and the rpm really picked up then it slowed right down and dies.
Plugs were blackened so cleaned them and it was hard starting again and after starting it did the same situation occurred.
Not sure how to describe this but it seems fine until warmed up and higher speeds are demanded then it says no thanks! Could it be dropping a cylinder at this point?
Once again I am open to any and all feedback and advice!
Thanks !
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Let the engine cool down and then went to run it
Started fine and once thermostat opened I gave her some throttle and it bogged down for a few seconds then started to catch up with rpm. It really opened up so I backed off a little and it stalled out. Quite a bit of smoke.
Started it again and this time I put the cover on the engine and agin the same thing except once the rpm caught up it bogged and stalled.
 
patiolatern said:
Is there a method to check this? Do I drop the lower to do a visual? I don’t see a lot of info on this. Thx
I see a lot of black in the barrel water so not sure if that’s an indicator or not.
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I have a lot of air being pushed out from prop when running. I just changed the barrel water and it’s clear.
 
optsyeagle said:
Did you try running it fast without the cover on the motor? Just wondering if you might have an exhaust leak.
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Just went out to do it just to make sure. It was slow to catch up to the throttle then it seemed to race up(a little scary hence the cover in the previous tests) then stalls out.
Not sure but the engine does sound loud on the top side of motor on the carburetor side and there could be excessive smoke out of that area….I think.
Could not visually see that area while it was running.
 
I read with amusement this thread. I am going to ask what is your fuel/oil mixture and type of gasoline? The previous owner used way too much oil? I believe that this motor is full of carbon, brother. I have made the 9.9/15's my motors of choice at our remote Ontario camps. Never ever had any problems with them running 100:1 Amsoil premix with non oxy premium fuel. Since 1976. Guests troll at 1.8 to 2 mph for Lake Trout for hours on end, then full speed back to camp....sometimes 10 miles. 16' boats. Replace CHAMPION spark plugs once a YEAR, whether I need to or not. (Sorry, little experience with NGK).
A reed valve problem is quite rare with these durable and simple 2 strokes....and reed valve would likely give continuous symptoms. (Would beg pardon from Racer....but yes, nothing is impossible. I just had a cracked reed valve causing problems on a mid 60's 3 hp twin). A leaky fuel pump diaphragm will overload the cylinder that it is operating off of. I remember something about replacing a fuel pump, was it a NEW one?
Okay hope this helps.
 
Honestly, I really don't believe the earlier "hybrid" 9.9/15's as being notorious for spark plug fouling. Just haven't seen it with any of my motors, some I am still running today. These are needle bearing motors and can be run at 100:1 with Amsoil synthetic premix. Some will argue, (thanks Racer), but I have thousands of operating hours on dozens of motors to prove it.
 
You can't properly tune a motor in the test drum....gotta get it on the boat that it will be used on. For most motors you can remove cover and aim a big fan to provide fresh air. Then you can get close.
 
I am running 50:1 accurately measured using regular gas (I use a fair amount of fuel so I will use ethanol free later in year before winter). This problem has occurred on two different fuel tanks.
Is 100:1 really the way to go? Wasn’t there a problem back in the day and the factory had to change or recall for the 100:1 to the current 50:1?
I am not familiar with the synthetic oil mixing.
I am thinking of doing up another batch just to make sure.
I do think there is a lot of carbon in this motor now and I see it in my barrel.
The fuel pump is probably about 15 months old but I did take it apart to examine and it(diaphragm)looked fine.
I am thinking of taking another look at it to double check it much like the carburetor check. Won’t hurt and maybe I missed something.
 
You can rest assured that if Johnson Evinrude made a mistake on 100:1, it was simply because they didn't specify FULLY synthetic oil. Even the old 9.5's are capable of 100:1. If a motor has crankshaft BUSHINGS....then I recommend 64:1 on Amsoil premix 100:1. Thats of course 2 oz per gallon. I have dozens of pre-needle motors with hundreds of hours operating time with that mixture. Ethanol is poison, you should stay away from it. Why? It dissolves rubber and most synthetic rubber. Its hell on crankshaft seals and diaphragms. Just diagnosed a 1999 50 hp Johnson on a pontoon boat today. VRO damaged by ethanol. Also water in the fuel. Ethanol "invites" water, it loves it. Why not let the water separate at the bottom of your fuel tank. I've even siphoned off or poured off the good fuel, cleaned out the water, then got back to camp. When your already paying $4 bucks a gallon for ethanol, why not just add another 75¢. Then you have fuel you can trust and fuel that will last 10 years in storage. With camps in remote Ontario, you really shouldn't take chances with your fuel. There is nobody around to help if your motor fails. But most men will take chances on fuel to save a few bucks....not me. Lives depend on it.
 
Racer suggested carbon in exhaust pipe/tuner. The powerhead must be removed for that to thoroughly clean things up. Then you could inspect and possibly replace the seal at the top of the cooling supply tube.
 
Did you ever try squeezing the primer bulb when the motor started acting up to see if it improved things at all?

The other issue that might be causing your problem is play in the stator, causing changes to your spark timing. The next time you have your flywheel off give it a shove in a few directions and see if you are getting play in that or if it is staying fixed in position.

As for the spark plug fouling problem, it really does not matter who is right or wrong. You have the motor you have. I found NGK withstand the problem a little better but once you get this particular problem fixed you can analyse that issue yourself. Changing the plugs annually will help a lot.
 
optsyeagle said:
Did you ever try squeezing the primer bulb when the motor started acting up to see if it improved things at all?

The other issue that might be causing your problem is play in the stator, causing changes to your spark timing. The next time you have your flywheel off give it a shove in a few directions and see if you are getting play in that or if it is staying fixed in position.

As for the spark plug fouling problem, it really does not matter who is right or wrong. You have the motor you have. I found NGK withstand the problem a little better but once you get this particular problem fixed you can analyse that issue yourself. Changing the plugs annually will help a lot.
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Yes I tried the primer bulb and it did not help. I also had the flywheel off and did not notice any play while I checked points etc. I will take the flywheel off and check specifically for play.
 
The other area of play that can develop in these motors is between the carb roller and the throttle butterfly that it controls. You confirmed your link and sync were good, where the arrow aligned with the middle of the carb roller just as the throttle cam contacted it BUT did the throttle butterfly start opening at thatexact time as well. So the link and sync is actually perfect when the arrow is in the middle of the carb roller when the throttle butterfly just starts to open. Sometimes there can be a little play build up between the carb roller and the throttle butterfly. You could attempt to look at the throttle butterfly hindge on the carb. You can see it on the starboard side of the carb. Some people put a little electrical clip on it and turn the twist grip and observe when that hinde/throttle butterfly actually starts to move/open and see if the arrow on the cam is aligned to the middle of the roller at that time. This method eliminates any play in that mechanism.

It may not be the issue but it doesn't hurt to check it out. It appears to me that whatever your issue is, it is probably going to turn out to be something weird.
 
optsyeagle said:
The other area of play that can develop in these motors is between the carb roller and the throttle butterfly that it controls. You confirmed your link and sync were good, where the arrow aligned with the middle of the carb roller just as the throttle cam contacted it BUT did the throttle butterfly start opening at thatexact time as well. So the link and sync is actually perfect when the arrow is in the middle of the carb roller when the throttle butterfly just starts to open. Sometimes there can be a little play build up between the carb roller and the throttle butterfly. You could attempt to look at the throttle butterfly hindge on the carb. You can see it on the starboard side of the carb. Some people put a little electrical clip on it and turn the twist grip and observe when that hinde/throttle butterfly actually starts to move/open and see if the arrow on the cam is aligned to the middle of the roller at that time. This method eliminates any play in that mechanism.

It may not be the issue but it doesn't hurt to check it out. It appears to me that whatever your issue is, it is probably going to turn out to be something weird.
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Thx. I actually saw videos with the clip and ignorant me did not put two and two together. Lol
There is the smallest of lag with the actual butterfly moving. I mean the lag is small less then 1/16
 
A 1/16" will not make much difference. Ignore that for now.

Perhaps we can recap the problem again since with all the testing you have done it would say that you should have a very well running motor.

To recap:

It starts up OK, idles not bad, then when you put it in gear and add power everything is fine until about 3/4 throttle and then it bogs down and eventually stalls and will not start back up right away. Is that what you are experiencing? Plus black looking spark plugs.

Later you confirm:

1) both cylinders are working
2) squeezing the primer does not change anything
3) You have good spark on both cylinders using an external spark tester set at 3/8" gap or higher
4) Cover on or cover off, same problem
5) Compression is good
6) Point Gaps set at 0.020" and no significant play in the stator plate

I assume later, she starts back up again. Other then cleaning the spark plugs are you doing anything else to get it to start back up again? Changing plugs for example or adding quick start to the carb or anything like that or does it just fire up again after resting for a period of time?
 
optsyeagle said:
A 1/16" will not make much difference. Ignore that for now.

Perhaps we can recap the problem again since with all the testing you have done it would say that you should have a very well running motor.

To recap:

It starts up OK, idles not bad, then when you put it in gear and add power everything is fine until about 3/4 throttle and then it bogs down and eventually stalls and will not start back up right away. Is that what you are experiencing? Plus black looking spark plugs.

Later you confirm:

1) both cylinders are working
2) squeezing the primer does not change anything
3) You have good spark on both cylinders using an external spark tester set at 3/8" gap or higher
4) Cover on or cover off, same problem
5) Compression is good
6) Point Gaps set at 0.020" and no significant play in the stator plate

I assume later, she starts back up again. Other then cleaning the spark plugs are you doing anything else to get it to start back up again? Changing plugs for example or adding quick start to the carb or anything like that or does it just fire up again after resting for a period of time?
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Great summary!!! But we just had a bit of a break!!
Double checked the fuel pump and it looked good but I don’t know the history of this pump but I believe it was changed about 15 -18 months ago by a service shop. To start back up I clean the plugs hit primer bulb once or so choke it once and pull then push choke in and pull 3 or 4x.
On to the break:
Doing a lot of testing and running some sea foam in the fuel to try and decarb this beast it was doing the same as described above but this time I jumped all over the primer bulb AND it actually brought it back to life. I was very aggressive with the primer bulb figuring what the hell!
It came back to life with heavy acceleration and I stayed on the bulb and could control with some more gentle squeezing and more regular. Smoked my neighbours out for a while then switched fuel lines to make sure it wasn’t bad. Same thing with other fuel line and the bulb would keep it alive. Plugs are black so cleaned them and stared up again so now I am running in gear at low throttle and no need for primer bulb.
 
Ok. So where are we? I mentioned the 6 points above because one of them almost had to be wrong. Are you now saying that squeezing the primer bulb keeps the motor running properly? This is very important. Low throttle and no need for manual operation of the primer bulb is interesting but what about wide open throttle? Let's face it. You didn't get a 9.9Hp motor to only get a horse and a half from it. It may work for trolling but this sucker should be able to roar.
 
optsyeagle said:
Ok. So where are we? I mentioned the 6 points above because one of them almost had to be wrong. Are you now saying that squeezing the primer bulb keeps the motor running properly? This is very important. Low throttle and no need for manual operation of the primer bulb is interesting but what about wide open throttle? Let's face it. You didn't get a 9.9Hp motor to only get a horse and a half from it. It may work for trolling but this sucker should be able to roar.
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Correct. I was able to get on the bulb earlier and harder to keep the motor running at the higher speed. Once I saved the engine from stalling I was able to do small squeezes of the bulb to keep it running. Hard to tell how well it was running since it fluctuates on my squeezes. I had about20-30 seconds max where I did not have to squeeze but would then play catch up with the fuel/squeeze. I had enough time to change tank fuel lines. I ran this way for 15 minutes or so.
At idle it seems to run ok with no need for the bulb to be squeezed.
 
OK. So you squeezed the primer bulb and the motor ran for another 20 to 30 seconds, at high speed. You then changed the fuel line and it ran without priming the bulb for 15 minutes.

Does that not sound like you have a problem with your fuel line?

Just so we understand each other, when you prime the bulb you are manually putting fuel into the carburetor. That amount is usually enough to run the motor for about 20 or 30 seconds. In proper operation your fuel pump would pump more fuel out of your tank, though the external fuel line, through the fuel pump and into the carburetor. If that is not happening it would be said that you have a fuel delivery malfunction, either in the fuel tank, the fuel line, the fuel pump or the carburetor. In your case it appears to be your fuel line.

So to be sure, have you taken the boat out on the water, with this 2nd fuel line and determined if it runs a idle, mid range and wide open throttle for as long as you want it to, without the need for you to manually pump the fuel to the motor?
 
optsyeagle said:
OK. So you squeezed the primer bulb and the motor ran for another 20 to 30 seconds, at high speed. You then changed the fuel line and it ran without priming the bulb for 15 minutes.

Does that not sound like you have a problem with your fuel line?

Just so we understand each other, when you prime the bulb you are manually putting fuel into the carburetor. That amount is usually enough to run the motor for about 20 or 30 seconds. In proper operation your fuel pump would pump more fuel out of your tank, though the external fuel line, through the fuel pump and into the carburetor. If that is not happening it would be said that you have a fuel delivery malfunction, either in the fuel tank, the fuel line, the fuel pump or the carburetor. In your case it appears to be your fuel line.

So to be sure, have you taken the boat out on the water, with this 2nd fuel line and determined if it runs a idle, mid range and wide open throttle for as long as you want it to, without the need for you to manually pump the fuel to the motor?
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We have some confusion. After saving the engine from stalling I continued to squeeze the bulb to keep running. While I was doing this I thought I would change this fuel line to eliminate this as part of the problem so I swapped the tank to motor fuel line. The problem continued with this different fuel line and I continued to squeeze the bulb to keep the motor running.
FYI: engine fuel lines were changed several months ago.
Someone gave me the idea to elevate the fuel tank to see if this eliminates or helps the issue and if not then I will go back to the carb I guess.
 
Well lets reduce the confusion because you may have isolated your problem.

I will assume then that when you said it ran for 15 minutes that you were manually squeezing the primer bulb from time to time to get it to do this or it would only run at low idle, not higher RPMs.

If the motor will run when you manually squeeze the primer bulb then you have isolated the problem to a fuel delivery problem. That means your issue lies in either:

1) External fuel line
2) Fuel tank - venting etc.
3) Fuel pump
4) Carburetor
5) Air leak with connectors or fuel lines

If a 2nd external fuel line did not fix things then that is not the problem. Fuel tank venting can be checked by unscrewing the cap on it and see if that fixes the problem or not. You have cleaned the carburetor enough times I would think. If you do it again a blow test for the inlet valve would be appropriate. That is where you blow into the inlet connection of the carb with it situated in both orientations. When the float is closing the inlet valve you should not be able to blow air into it and when the float opens the inlet valve there should be no restriction of air. Do you have the little spring on the float to make sure the inlet valve is not sticking. That can be your problem as well. Air leaks on fuel lines are a visual thing to check. The connectors on the fuel line are verified by the 2nd fuel line you used so they can probably be eliminated. Visually check all other connections for air leaks. Lastly, with the carb disconnected, give the pull start a pull and see if the fuel pump shoots fuel out the end that should connect to the carb. If it does, the pump is probably working and if it does not it probably isn't, although as stated above there are a few things that will prevent fuel from flowing other then a bad fuel pump.

Anyway, that is what I would do.
 
optsyeagle said:
Well lets reduce the confusion because you may have isolated your problem.

I will assume then that when you said it ran for 15 minutes that you were manually squeezing the primer bulb from time to time to get it to do this or it would only run at low idle, not higher RPMs.

If the motor will run when you manually squeeze the primer bulb then you have isolated the problem to a fuel delivery problem. That means your issue lies in either:

1) External fuel line
2) Fuel tank - venting etc.
3) Fuel pump
4) Carburetor
5) Air leak with connectors or fuel lines

If a 2nd external fuel line did not fix things then that is not the problem. Fuel tank venting can be checked by unscrewing the cap on it and see if that fixes the problem or not. You have cleaned the carburetor enough times I would think. If you do it again a blow test for the inlet valve would be appropriate. That is where you blow into the inlet connection of the carb with it situated in both orientations. When the float is closing the inlet valve you should not be able to blow air into it and when the float opens the inlet valve there should be no restriction of air. Do you have the little spring on the float to make sure the inlet valve is not sticking. That can be your problem as well. Air leaks on fuel lines are a visual thing to check. The connectors on the fuel line are verified by the 2nd fuel line you used so they can probably be eliminated. Visually check all other connections for air leaks. Lastly, with the carb disconnected, give the pull start a pull and see if the fuel pump shoots fuel out the end that should connect to the carb. If it does, the pump is probably working and if it does not it probably isn't, although as stated above there are a few things that will prevent fuel from flowing other then a bad fuel pump.

Anyway, that is what I would do.
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Thanks!
I will be back on this motor in a couple hours.
I do the blow test on the inlet every time I take it apart and I do have the retainer clip on the inlet valve connected to the float but will double check if/when I take it apart.
Does anyone have the specifications on float position for this motor? It’s a pretty shallow bowl.

I will double check the fuel tank venting as well as the other ideas you had.
 
One more thing I forgot to mention on my list above that could very well be the culprit. Check the fuel filter screen that is in your fuel pump. It could be 85% clogged up with gunk and that could certainly cause the problems you are having.

Float should be level with the carb body when it is held upside down.
 
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