1988 Johnson 9.9 Carb issue.

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Oct 13, 2012
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Hello. I recently acquired a 1988 Johnson 9.9 short shaft. I knew when I purchased it that it had an issue staying running.

I tested the motor on the sellers boat. It would start fine, but only run for about 30 seconds, and then would die, unless the primer bulb was pumped and the choke had to be all the way out the whole time.

I immediately suspected the fuel pump. Having to squeeze the bulb was what clued me into that, so I took a gamble and bought the motor. It looks great, clean and other than the staying running part (I know, pretty important part) I thought it was a safe gamble and am willing to do the work to get her running right.

It has been unseasonably cold here in N.E. Ohio so I did not get a chance to run the motor again for a few weeks.

When I finally got the chance, I found that I was unable to start it without first squirting some 50:1 into the breather even though I primed the ball till hard. When it did start, it was the same deal as before. Run for very brief time, die unless pressure is put on the bulb. Choke must remain pulled all the way out the whole time. Push it in and the motor dies instantly. (I have motor in barrel for testing)

The gas tank is good. Hoses/connectors are brand new. (old metal tank, been cleaned and inspected and new gasket around gauge so I am confident about everything "off motor")

Ok..so I decided to start with the fuel pump and the hoses. Replaced the longer hose from the tank line connector to the fuel pump, and replaced the smaller line from the pump to the carb. Also replaced the pump itself with a new pump.

I did test the original pump by pulling the fuel hose from the carb and gave the rope a small pull. Gas squirted right out so it was pumping, but I thought perhaps when connected it was unable to push it all the way into the carb. I was still praying for it to be just a simple fuel pump issue. One of the easiest repairs, so like I said, I replaced it.

That did not help at all. Same problem. When I was at the marine shop I picked up a can of Sea Foam carb spray and a can of Sea Foam fuel additive. I used the spray by squirting it into the air intake (after I removed breather). (did not use additive so far) Turns out I am able to keep the motor running, albeit very rough and with crazy smoke, by spraying the Sea Foam cleaner into the throat. I did not do this a whole lot because I did not want to risk damage due to possible lack of lube in cylinders. I then let the motor stall, sprayed more cleaner, let sit, ran through, no help.

Now I have taken the carb off and am waiting for a rebuild kit to arrive. I got the one with a float included.

QUESTION: Does the 1988 originally come with a cork float? The one that has been in this carb is black and does not appear to be cork like the ones I have seen on older models. I am wondering if this carb has been redone before.

The carb that I have is the plastic top and plastic bowl. In the bottom of the bowl there was a slight film of sludge, nothing I would consider gritty. There are some darker colored areas here and there (shall I call it varnish?) inside the body but not bad.

The float needle seat was probably the most colored. Varnish all around it. The needle had some color to it as well. I am hoping this was the problem. The needle perhaps getting stuck in its seat once the float pushes it in and preventing fuel from entering. I dunno, wishful thinking I guess.

I am soaking the body now for 24 hours in carb cleaner. I am also looking for some diagrams so that I can locate each of the holes that I need to clean. I read that a thin piece of wire works well. I do not have an air compressor but I am considering getting a small can of compressed air (the kind you would clean a computer with) to blow in the holes.

I will post back with the results of the carb rebuild once it I am done (parts are due Friday or Monday if eBay seller fills the order as descibed).

My main concerns at this point:

Obviously worried that this wont fix the issue and that it is a greater problem, worst case scenario I have read is that a leaking "lower crank seal?" may not be allowing a vacuum to pull fuel into system.

Also read something about bad piston skirts creating a lack of fuel. I don't mind rebuilding a carb (kinda fun) but not sure about pistons and cranks. That makes me a little nervous.

You know...they say when you are sick, never look up the symptoms on the internet because by the time you are done reading you will have convinced yourself you only have 3 days to live. I am trying my best not to do that with this motor.

But just in case, tell my family I love them. (ok...now the post just got a little creepy!)

I appreciate anyone who would like to chime in.

Thanks for reading,
Chris - LouisvilleFisherman
 

Rick.

Captain
Joined
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Re: 1988 Johnson 9.9 Carb issue.

Start simple and then work your way into the incurable diseases, LOL. You are on the right track. Your cylinders are not getting fuel and your carb. is the likely suspect. Clean all the holes from both directions. Compressed air is IMO essential. It would not hurt to check your compression either. Too bad you didn't ask before the fuel pump but a new one on that old a motor isn't money waisted really. You did good putting new fuel lines on before the carb. cleaning. Crank seals, reeds and that stuff should be put on the back burner for now. Best of luck. Rick.
 
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Messages
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Re: 1988 Johnson 9.9 Carb issue.

That is why I did not mind too much about replacing the pump, I figure it was one less thing to worry about in the future, especially considering the ethanol.

I would like to check the compression, but have yet to purchase a gauge. I may do that tomorrow if I can find one inexpensively. I'll post results if I end up with one.
 

OptsyEagle

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1,356
Re: 1988 Johnson 9.9 Carb issue.

For your motor to die, both crankcase seals would need to be bad. I doubt that so I wouldn't worry about them now. I think it is the carb. Gunk in the slow speed jet (why it needs a choke) and possibly gunk sticking the inlet needle (why you need to pump the primer bulb manually to keep it going). Was there a little spring clipped to that inlet needle and the float arm, when you took it apart? There should be. Anyway, clean that carb good. Compressed air is your friend when cleaning out carbs. Lots of carb cleaner, then blow with compressed air, then lots of carb cleaner, blow with compressed air. Sure, poke a soft metal (copper) through the slow speed and high speed jet area and any other holes you find, then lots of carb cleaner and blow with compressed air.

If that motor has a welch plug, make sure you clean that out as well. Lots of carb cleaner then blow with compressed air.

I'm a broken record now, so I will quit. Good luck.

One last thing. If you get it to run, without the choke, then your carb is clean. If it still dies in 30 seconds or so, requiring you to pump the bulb again, then go back and look at those devices that you are so confident in. Is the tank venting properly? Just unscrew the cap to confirm. Does the tank hose operate well. Here you need to verify the check valves are working right and the connector seals sealing. Best way to test is to try another hose.
 
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Messages
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Re: 1988 Johnson 9.9 Carb issue.

Does anyone know if there is a diagram or a picture of where all the holes are that I need to clean. I see a series of small holes on top of the carb body, are those it? I just don't want miss anything.

Yes, I have checked the venting. I have tried with the cap on and off. The hose is brand new, feels snug. No leaks when I get a solid bulb. The motor did not come with a tank or hose, yet was exhibiting the same problems with the previous owners tank/line. But anything is possible I guess. I am not beyond visiting those areas should all else fail.

Thanks for the reassuring replies fellas. I appreciate the fact that I am not hearing things like..."oh my your motor is probably shot" or "do you have a will?". :)
 

Rick.

Captain
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Re: 1988 Johnson 9.9 Carb issue.

Well we assumed you had a will! One more thing. Those carbs with the plastic cover are know to crack and suck air. Do a very careful inspection of the plastic. Rick.
 

Jim Hawkins

Chief Petty Officer
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Mar 11, 2013
Messages
499
Re: 1988 Johnson 9.9 Carb issue.

In the parts diagram for that carb I don't see any parts that need the wire treatment but if you give the whole carb a good look you will be able to tell if there are any. Consider taking the carb somewhere with access to an air compressor, maybe a friend has one. I use a lot of air to blow back and forth thru every hole. Also, I used to take the carb from the dunk bucket and go right to blowing air through it but now after dunking I dunk it again in hot soapy water and give it a good wash and rinse and then blow dry.
 

w2much

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Re: 1988 Johnson 9.9 Carb issue.

Yup yer gonna die. Those plastic carbs should not be soaked in cleaner overnight. As Rick said they also have a tendency to warp and suck air. Try to hook your fuel line directly to the fuel pump inlet, this will eliminate sucking air instead of fuel to the pump through faulty connectors. Sounds like a carb issue (sticking needle) dirt in air passages. As stated above blow air through all of the passages. Welch plug may have some trapped sediment inside or could even be leaking air. Good luck.
 
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Re: 1988 Johnson 9.9 Carb issue.

I removed the body of the carb from the soak after only an hour as I read elsewhere that they should not be soaked. I only put the metal body in the soak and not the plastics. I will go out and inspect the plastics for cracks and warpage. I gave them a quick look over when in the garage and they looked solid and straight but I will bring them into the house on a nice flat/clean counter top and check again.

To answer a previous question, yes there was a small spring holding the float needle in place. It looked fine, I took plenty of close up pictures so that I mount it back on properly.

As far as the welch plugs, I cannot find them and I read on a previous thread that that the plastic tops may not have them. Can anyone verify that or am I just missing them.

I spoke with a buddy last night and he is going to let me borrow his portable air compressor.

Still waiting for the rebuild kit to arrive.
 

OptsyEagle

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Re: 1988 Johnson 9.9 Carb issue.

If you go to the BRP site here. http://shop2.evinrude.com/Index.aspx?s1=4ssm1kklb6k8dpcfml6p409sr5&catalog_id=5&siteid=1

and look up your model of motor it shows two types of carburetors. The standard one has the plastic top and it doesn't look like it has a welch (core plug) plug on the top. I suspect the plastic cover seals it up. The other type of carb is metal by the looks of it (P/N 397722) and has the core plug in the top of it.
 
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Re: 1988 Johnson 9.9 Carb issue.

I definitely have the plastic version. I checked it for warping and cracks and it looks as flat as I can tell. Its impossible to lay it perfectly flat because of a "hump" on the corner portion of plate, but when I hang that part over the side of the counter top, the rest looks nice and plane.

I do not see any welch plugs to tap out anywhere on the body or cap. With that said, am I going to be able to clean whatever was under those plugs considering I do not have any?

My nozzle well (part #2 on the schematic) is made of plastic and shows considerable wear where the little brass hose attachement goes into the base. It does not appear broken, just a slight crack that does not appear to be all the way through. This little plastic piece is listed at $45. Ouch. Not sure how the wear could have gotten there, as no moving parts reach that area. It literally looks worn. I did not bring a picture of it to work with me (where I am at now).

I do however notice a difference in another area of the carb, the cam roller. I have attached a picture of mine. Others I have seen online show a yellow plastic "sleeve" that sits inside the roller. Elsewhere on this forum someone posted a picture of theirs and the sleeve was broken. Does mine in the picture look normal, or is it missing this sleeve, or jacket if you will.

If it is missing, does something that small (sleeve on a roller) matter? Its only $20 but man this stuff adds up quick. I need to be prudent about the budget. I cannot imagine it has anything to do with my current running issue.
camroller.jpg
 

the machinist

Senior Chief Petty Officer
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May 7, 2002
Messages
711
Re: 1988 Johnson 9.9 Carb issue.

Yep, the sleeve is missing. I agree that it should not have anything to do with your issue, but it surely will effect your speed anything above an idle.

As a sidelight to this, I went out to check my 92 roller & the sleeve was broken, with only about 2/3rds of it still on the arm.
 
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Re: 1988 Johnson 9.9 Carb issue.

I picked up on the missing sleeve when I was reading an old thread about pulling a carb. The OP of that thread also had a broken sleeve still 1/2 on the roller. I am guessing that I cannot simply "adjust" my way out of this one and will need to replace it? I wonder if I can come up with some sort of fix.

For what its worth that thread proved to be the most informative thread pertaining to pulling a carb I have found yet. Especially the part about removing the pull starter. I would never have used a c-clamp and tape to hold it together if I had not read that thread. I am positive I would be left with a sprung winding, a lost washer and perhaps an injured eyeball.
 
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Re: 1988 Johnson 9.9 Carb issue.

Progress report:

As I mentioned I did not soak the plastic parts which includes the nozzle well. This is the same part that I talked about a few posts up that has the wear on it. Well there is a tiny little brass pipe that has a little rubber hose hooked to it on the base of the nozzle well. That pipe was solid clogged. It took a sewing needle and some effort to clear it out.

That was the only clog that I was able to see or feel, but I did make sure I cleaned and poked every hole I could. I am borrowing an air compressor tomorrow so I will continue to clean until the rebuild kit arrives in the next couple of days.
 

Jim Hawkins

Chief Petty Officer
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Messages
499
Re: 1988 Johnson 9.9 Carb issue.

Before you take the air hose to it, give it another soak in case anything has dried and hardened. Please post a link to that informative thread you mentioned. I also found it very helpful some time ago but don't think I bookmarked it. My guess is that pipe that you found clogged is your problem.
 

Rick.

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Re: 1988 Johnson 9.9 Carb issue.

bktheking helped so many. I often wonder what happened to him. Maybe burn out? Anyway, all you need to keep the recoil intact is a 3/8ths coarse thread nut and wind it on the center bolt. It will hold everything in place. Best of luck. Rick.
 
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Re: 1988 Johnson 9.9 Carb issue.

I have good news and not so good news.

I rebuilt the carb. It now runs without the choke out. I do not have to spray 50:1 into the carb to start it either. Situation has improved.

Unfortunately it still wont run longer than 1 minute. I have went over everything. Replaced and tested the fuel pump. Working. Fuel lines new. Tank line new. Bulb new. The tank is an old metal tank. It is supposedly self venting through the cap but I took the cap off just to be sure.

The bulb pumps up nice and solid. No leaks, unless I squeeze really really hard and then some fuel will leak out around the metal clamp on the output side of the bulb, but like I said I have to squeeze real hard. Does anyone else's do that if you squeeze real hard?

I am just grasping at straws here, but I cannot figure this out. I mean, if there was an air leak between tank and carb, wouldn't the fuel pump test fail? (by test I mean when I unhook fuel line from carb and pull rope, gas squirts real good out hose.)

I feel like the float is working properly because I did a blow test when I was assembling it and the needle functioned well. New needle, new seat, needle clip on proper.

I guess the next step is to eliminate the tank, hoses and pump from the picture.

I read somewhere about building an IV drip style fuel source. Essentially a 2 liter bottle with bottom removed, inverted with some sort of hose attachment in bottle cap hung above motor with line running directly into carb.

Like I said, I have made progress, but still not running longer than 1 minute.

Any thoughts?
 

Rick.

Captain
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Re: 1988 Johnson 9.9 Carb issue.

Before you try that, try elevating your tank well above the engine. A couple of feet higher. At that point you have a gravity feed fuel system once the motor is started and it should eliminate any pump concerns. IMO it is probably either your pump or the carb. float is sticking closed. Your fuel line should not leak no matter how hard you pump it so I would fix that ASAP. I know you have an aggravating problem but stick with it and you will solve it eventually. Rick.
 
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Re: 1988 Johnson 9.9 Carb issue.

Unfortunately I already had the tank elevated.

I rebuilt the carb and replaced the float, needle, o ring and seat with new stuff. I tested the needle by blowing into the input with the carb right side up and with it upside down and it stopped the air flow, and when I turned it back over it flowed again. I did this both before and after assembly. As fragile as plastic top is I dread having to take it all apart again.

I am almost willing to buy a carb that has been rebuilt and tested so that I can mount it and see if that fixes it. If it does, it would be worth it if the price wasn't too high. I see them for around $150 but that is not tuned and tested. Anyone ever hear of such a thing as a carb that is ready to run?
 
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