35 hp Johnson Lean Sneeze / Pop causes

[bktheking]

Re: 35 hp Johnson Lean Sneeze / Pop causes

When you had the reed plate off did you shine a flashlight on it in the dark?

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

No I did not. What would I be looking for and what would that tell me?

I checked all the reed valves and cleaned all of the surfaces before putting new gaskets on.

 

[G DANE]

Re: 35 hp Johnson Lean Sneeze / Pop causes

One thing I would suggest you to check, is that the fuel pump diaphrame isnt leaking into upper intake thru by-pass chamber.
If it does, situation can be, that pump feeds upper and you lean lower out, by trying to adjust lowspeed mixture. Lower will sneeze. It looks like your upper is running rich and lower too lean by the looks of the exhaust.

Same situation can be caused by leaking piston skirts, though. Take pump off bypass cover and pump bulb firmly to check no fuel leaks out of pump thru pulse hole. Let us know what you find.

Did you try to let both sparks jump a 3/8 or 5/16 gap ? They should be able to du so, a weak spark can act like fuel problem, too. Not rare on those point ignition ones.

 

[G DANE]

Re: 35 hp Johnson Lean Sneeze / Pop causes

One more thing to check is that the little keyhole shaped silicone gasket around the low speed needle is sealing properly. If it isnt, your possibilities of adjusting micture is limited. Same for both cylinders, though.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

I pulled apart the fuel pump to make sure it was operating correctly but I will check as you say and see that it is. If I recall correctly, there was only 1 small hole on the back.

I will also check my spark plug jump to see if that might be it.

When I did the carb rebuild, I made sure to replace that low speed idle screw keyhole gasket and screwed it in so the low speed screw made the grooves. Screwed it in once all the way in til it seated then backed out 1-5/8 turns (manual recommended to start).

I hope its not my piston skirts but would I still get good compression even if my piston skirts were scored?

 

[Cofe]

Re: 35 hp Johnson Lean Sneeze / Pop causes

FR Wrote:
Reguarding your previous question, good compression only indicates the rings are doing their job. Unlike a 4-stroke, two strokes have to have crankcase compression. The piston skirts seal off the exhaust area from the crankcase. Crankcase leaks are also related in that they admit air to the crankcase.[/QUOTE]

FR is right on about piston skirts sealing off exhaust from the crankcase.

I was reading some history here on carbs, and some people can only get theirs to idle at 2-1/2 turns on the low speed needle valve.

 

[bktheking]

Re: 35 hp Johnson Lean Sneeze / Pop causes

No I did not. What would I be looking for and what would that tell me?

I checked all the reed valves and cleaned all of the surfaces before putting new gaskets on.

Gaps between the reeds and the plate that you might not see. I'm thinking crank seal at this points, I mentioned upper in my past post, i'm going with lower like F_R said, his logic is correct (as always)

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

G DANE,
I guess I dont follow on your fuel pump info. Im not very knowledgable on this so I apologize if I ask too many questions. My fuel line goes to the fuel pump and another line from the fuel pump goes to my carburetor. There is a small hole in the middle back of the fuel pump. Where does that go or what does that do? Is that the pulse hole your referring to?

F_R,
Sounds like you have a lot of respect from others around this forum. Im sure your advice has helped out a lot of people.

Now in regards to the crankcase seal....I was told to spray carb cleaner around where the crankcase and cylinder housings come together. If it was a crankcase seal, it would get sucked in and smooth out. I did this with no success. Is there another way to check that? Is there a way to check the piston rings? If I end up having to pull the powerhead apart, Id like to be confident thats the cause.

Thanks for all the continued help everyone.

 

[bktheking]

Re: 35 hp Johnson Lean Sneeze / Pop causes

That would be the top seal, the bottom seal you can't get to without pulling the powerhead.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

In that case should I try pulling off the coils, and pulling off the By-Pass Cover (behind the fuel pump) and replacing the By-Pass Cover gasket? .....I think that is what G DANE is referring to.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

*UPDATE*
I was looking at the ignition coils and intake area yesterday and why I didnt notice this before I couldnt tell you but I found something that looks abnormal. Can someone tell me what the heck this is. Look at the pics. This is in between my iginition coils and my fuel pump on starboard side of my motor. It looks like a very large core plug and looks like it has a drilled port hole which might lead someone to the ignition chamber. It also looks like this should have a cap on it because it has a lip, very similar to a core plug on the carburetor except larger.....about the size of a quarter.

I havent had a chance to start up my motor yet to see if this is sucking in air and therefore causing my lean sneeze, oily upper plug and hot lower plug, but I thought I should find out what this is first and if it should have a cap on it. I cant find anywhere in my service manual anything about that but it does in fact look like it should be capped.

I dont know if I feel happy or sad because Ive done so much to this point and if this is my problem it seems too simple to be true. Plus the fact that I didnt notice this before makes me feel fairly embarrassed.

Can anyone explain to me what exactly that is and what purpose it serves. Also if it should be capped and if so why would it become uncapped? Thanks.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Here are the pics.

 

[bktheking]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Looks like where the metal plug where the SN stamp was, is that still on the motor? If not then that's where it was, doesn't need to be on the motor to make it run properly.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

The serial # is actually on the other side of the motor, but I looked at a different motor and that one did have the S/N stamped on it and it was covered.

Inside this port there is a small hole which looks like it leads to the ignition chamber but Im not sure. It looks as if it was once drilled out from the back of the motor towards the front. My service manual shows pics of the motor and in each pic it shows a cap over that. Im still curious to know its function or why it needed to be drilled out in the first place?

....after further investigation, Ive found that its called a welch plug or freeze plug. What I havent found is why someone would have needed to drill the hole.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

I was told to spray some oil directly into the intake and see if that helps at all. This would indicate that there is something with reeds or intake. I did so yesterday and no changes.

Also, when I remove the bottom spark plug it runs smooth on 1 cylinder. When I only remove the upper then it runs rough and nearly stalls. Due to my compression tests and spraying oil into intake possibly eliminating powerhead seals, could this be linked back from my plugs and be my lower iginition coil or even further back to my points?

Is there a way to test the ignition coils? Still stumped!

 

[rockfinder2]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Check to see if the points are gaped properly and the armature plate doesn't move from side to side allot when you check it with the motor stopped.

 

[redbeard361]

Re: 35 hp Johnson Lean Sneeze / Pop causes

One more thing to check is that the little keyhole shaped silicone gasket around the low speed needle is sealing properly. If it isnt, your possibilities of adjusting micture is limited. Same for both cylinders, though.

This is what was causing my "sneezing", it was nicked up pretty bad. Put a new one in there, screwed the adjusting screw back in and the results were instant. Sneezing was gone at idle, throttled up just fine, problem solved. Strange how a little thing like that will cause so much trouble.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

I switched around the ignition coils to see if the problem would follow but no changes. What still happens is if I remove my lower spark plug boot, it runs smooth on upper cylinder, but when I remove the upper spark plug boot, it sneezes and eventually stalls. Does this tell me that my ignition coils and everything back from there is ok?

I started a new thread and posted a link to a video of it running when I did this test. Go to this thread and it explains better. Do I need to do a rebuild?

http://forums.iboats.com/showthread.php?t=398529

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Well here is an update because it has been a while. I finally decided to rebuild because of piston scoring and other misc possibilities.

Ive finally got everything rebuilt and ready to drop back in the motor. Everything went ok and some better than I expected. Took me a long time but reading and re reading the service manual along with patience gave reason as to why its taken so long. No real difficulties but a couple of concerns that I hope will not be problems.

First, when I replaced the lower crank seal, I had to use a punch to drive out the old one. What I got as a replacement part apparently replaces that seal and has a different design and made out of rubber. I believe I had installed the correct way but the instructions didnt specify the correct direction. I installed both the upper and lower crank seals to have the cupped side face the center of the shaft.

Second, when I applied the gel sealant to the grove in the crankcase and bolted the crankcase to the cylinder case, will it be a problem if some of that gel sealant oozed out on the inside of the crankcase. Will that eventually be able to work its way out because I was told that it will not dry or harden.

And finally, my manual told me to temporarily reattach the flywheel and turn it so make sure there is no binding. When I did so everything moved smoothly but it was a lot more difficult to turn the wheel compared to before. Is this typical? Also before I rebuilt, when I would turn the flywheel, it would "release" a little when the crank is at the beginning or end of its cycle. So to explain this better, I would have to turn the flywheel about 120 degrees and then it would almost automatically (like spring loaded) turn the remaining 60 degrees by itself. Well after this rebuild it doesnt do that at all and needs a constant torque to turn it. Is that normal?

I plan to start it up this evening so hopefully if all goes well I will have a video for everyone. Thanks for all the help and support everyone.

 

[bktheking]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Run double the oil if you did the rings, good job on the rebuild.It's more difficult to turn cause the rings aren't seated yet, if you did indeed replace the rings.