1955 Johnson 5.5

[jbjennings]

Re: 1955 Johnson 5.5

For whatever reason, your spark is weak. As far as I know, the spark should never be orange when the system is working properly-- if there's enough voltage to cross whatever size gap you have, it should be blue or not cross the gap at all. Regardless of whatever else is wrong, if you squirt a little fuel/oil mix in the spark plug holes and spin it over, if you have good compression and good spark it will fire off for a few seconds. I'm betting that you can spray fuel in there and it won't fire on its own at all----because the spark is enough to cross the gap in open air, but too weak to cross the gap with air and poorly conductive fuel/oil inside the cylinder. The fuel never combusts......

My suggestion is redo that ignition until you get it right, or take it to an expert and let them fix it. Without proper spark nothing else matters.

 

[derrTderr]

Re: 1955 Johnson 5.5

OK, I sprayed some premixed directly into the cylinder and gave it a crank. With a medium strength pull the motor turned over five or six times before going dark again.

The carburetor needles are not loose. They are adjusted 1.5 turns and 3/4 turns out, slow and high speed respectively.

When I put a screwdriver to the inside of the flywheel when I had it off, it was magnetic on one side. However, when I hold a screwdriver to the outside of the flywheel, there is no pull all the way around. Do I have a bad flywheel?

 

[nwcove]

Re: 1955 Johnson 5.5

the importance of the magnets is strictly on the inner circumference of the flywheel, but weak magnets ( rare) will result in weak spark. ( do not dwell on the weak magnet thing....its almost unheard of with those motors)

 

[HighTrim]

Re: 1955 Johnson 5.5

You have a fuel delivery issue, if it ran for a couple seconds on the spritz of fuel.

If you are certain that fuel is filling the float bowl, it is not getting pulled up through the carb to the cylinders.

 

[Crosbyman]

Re: 1955 Johnson 5.5

back to basics is this engine sucking air in the carb front with the air silencer taken off

Did you check inside that air silencer to see if long legged critters did not set up shop.

take off the silencer to finger test the air draw into the crankcase. That motor runs when you feed it gas but it should suck gas on its own now. it is old enough


btw... you did check the reeds.... thay are not stuck shut are they ???

 

[derrTderr]

Re: 1955 Johnson 5.5

I've been trying to run the motor with the silencer off so I could access things easier. All the same, I disassembled the silencer and it is clear.

I pulled the starter with my fingers covering the intake and couldn't really feel any suction (choke full and choke off). How noticeable is the air flow supposed to be? Could the motor be starved for air and not fuel?

I have the pump plumbed as follows: fuel line from tank connector to fuel in arrow on pump, fuel line from fuel out arrow on pump to inlet on the bottom of the carburetor, and I have a section of fuel line running from the outlet on the bottom of the intake manifold to the center inlet on the pump.

Even if the fuel pump isn't working right, the primer bulb on the tank line should fill the carburetor bowl, right? And that should be enough fuel to run the motor for at least 30 seconds or so I figure. As is, the motor won't run for longer than it takes to retract the starting cord.

I rechecked the plugs with the inline tester and they spark regularly but the spark is definitely orange and looks kind of weak. It doesn't have a big blueness to it like I would think.

I think I need to revisit the ignition and rebuild the carb again, but I'm not sure what I should be doing differently in each of those.

 

[derrTderr]

Re: 1955 Johnson 5.5

btw... you did check the reeds.... thay are not stuck shut are they ???

Reeds? I have a friend named Reed.

Seriously, what are these reeds you speak of?

 

[jbjennings]

Re: 1955 Johnson 5.5

Just behind the carb in the intake manifold is where the reed valves are located. They let fuel and air in when the piston goes up and produces vacuum, and prevent air from leaving the crankcase through the carb so that the crankcase pressure pushes fuel into the cylinders via the bypass when the piston goes down. They're a one-way check valve basically. Sometimes bugs can block the reeds open and the engine can't push the fuel to the cylinders, or corrosion can stick the reeds to the reed blocks and therefore the fuel and air can't enter the crankcase. Either condition would prevent fuel from getting to the cylinders. My vote is still spark---or just too low compression.
Hope this helps,
JBJ

 

[geoffwga1]

Re: 1955 Johnson 5.5

Reeds? I have a friend named Reed.

Seriously, what are these reeds you speak of?

The reeds are leaf valves that allow fuel into the crankcase from the carburetor.They are the thin springy plates attached to the plate between the manifold and the crank case.Part # 202667. When the piston rises a vacuum is created in the crankcase drawing in fuel,on the downstroke the crankcase is repressurised forcing (hopefully) the reeds closed.This pressurisation also creates the pulse to activate the fuel pump if every thing has been correctly installed when you did your conversion from dual line.I doubt that there is a problem with the reeds unless you did something wrong at that time.I'm leaning towards ignition now and I think it was JB who said we need to go back to basics and go through everything from the magplate out.It is very easy even for the experts to miss some tiny seeming thing that can make all the difference.above all,don't despair,you will get a great feeling of satisfaction when you finally crack it and you'll have a great little motor that will probably last for most of the rest of your life with minimal maintenance.
PS.I'm abit concerned at the lack of suction at the carb mouth so take a look at the reeds anyway.
Geoffwga1

 

[geoffwga1]

Re: 1955 Johnson 5.5

Just behind the carb in the intake manifold is where the reed valves are located. They let fuel and air in when the piston goes up and produces vacuum, and prevent air from leaving the crankcase through the carb so that the crankcase pressure pushes fuel into the cylinders via the bypass when the piston goes down. They're a one-way check valve basically. Sometimes bugs can block the reeds open and the engine can't push the fuel to the cylinders, or corrosion can stick the reeds to the reed blocks and therefore the fuel and air can't enter the crankcase. Either condition would prevent fuel from getting to the cylinders. My vote is still spark---or just too low compression.
Hope this helps,
JBJ

Sorry there Captain.I guess you were posting your answer(post68) while I was still composing mine(69).Though it seems we were saying roughly the same thing in slightly different ways.
Geoffwga1

 

[jbjennings]

Re: 1955 Johnson 5.5

A few questions:
What kind of spark plugs? J6C, J4C, but not JC6.
Do you have orange spark on BOTH wires??? What's the gap on the tester when it's orange?

I can't really think of any other likely places you could have messed up on with that ignition. What's baffling me is that usually you don't get them messed up so that BOTH wires have orange spark.


One of them is usually good and blue. This makes me lean toward a possible points misadjustment. If you had it running at one time, I doubt compression is the biggest problem unless you got it too hot the last time it ran, or ran it with too little oil in the fuel.
I hope you figure it out and post what happened. I'm curious for sure, now.

I reread your first page and thought I might have an idea:
I noticed you said that you made your .020 adjustment when the rubbing block was at the keyway. If I recall, that may not be correct. The .020 points adjustment should be made when the rubbing block hits the highest point on the points cam, which is not at the keyway I don't think. It's been a few months since I set the points on mine.

 

[Crosbyman]

Re: 1955 Johnson 5.5

"I pulled the starter with my fingers covering the intake and couldn't really feel any suction ...."

you should feel strong sucking if your fingers are flat against and closing up the carb face.

IMHO you proved that timing & fumes ignition is working properly or to some extent anyway ....by squirting some gas in the plug holes.

You now need to get this gas/air mixture directly inside those piston chambers from the front to the rear of the engine.

now is the time for straight answers to straight question....to get this engine working

did you inspect the reeds ?

can you do what is required to get the air/fuel sucked in properly ? if yes we can go back to worrying about sparks If no don't worry about the sparks

 

[derrTderr]

Re: 1955 Johnson 5.5

After reading your responses, I'm going to remove the carburetor and inspect both the reeds and go through the process for installing the fuel pump. I'm starting to think that I may not have done that properly.

I don't remember what the spark plugs are, I will look that up tomorrow as well. I'm also not sure I had the spark tester set at 1/4". I've never used a spark tester before and I'm not sure how to set it to 1/4".

I know I have issues with fuel delivery and ignition and possibly compression. I seem to be going from one issue to the next. I think you guys are right about going back to basics. I rebuilt the lower unit today, tomorrow I'm going to go through the fuel system and confirm it's condition. Hopefully I can verify that everything is working there and can then pinpoint the problem to the orange spark issue.

 

[HighTrim]

Re: 1955 Johnson 5.5

It sounds like you might be using a neon tester, in which case the orange spark is normal. The adjustable testers are very obvious how to adjust the gap.

 

[jb93]

Re: 1955 Johnson 5.5

I'm way late to the party here, but had a similar issue with restoration of my 1957 Fastwin that I thought relevant enough to share. I had spark, compression and if I sprayed fuel into the throat of the carb she would kick off and run for a few seconds. Turns out I had installed the float upside down when I rebuilt the carb. In that orientation, the float was compressing the needle against the seat and not letting any fuel into the carb. I flipped the float over and motor started first pull. You are almost surely not as mechanically dense as I am, but maybe the float is not set properly?

A way to check this is take the carb off and hold it upside down from the way it is installed...can you blow air through it by blowing on the fuel inlet hose? If not, then the needle is seated/stuck and won't left fuel in. Likewise, if you hold the carb in same orientation as it is installed you should NOT be able to blow air through the fuel inlet hose.

 

[jbjennings]

Re: 1955 Johnson 5.5

It sounds like you might be using a neon tester, in which case the orange spark is normal. The adjustable testers are very obvious how to adjust the gap.

That would also explain why BOTH wires are producing orange spark....... :blue:

 

[Crosbyman]

Re: 1955 Johnson 5.5

imho

weak sparks or inverted floats are not explaining why this engine is not pulling enough air/fuel from the carb face. air anyway !

without sufficient fuel and oxygen being pulled in to fill the chambers everything becomes a second priority
and to get fuel inside enough air must fill its lungs first !

works like a canon.... powder first... compress everything then.... light the fuse

 

[derrTderr]

Re: 1955 Johnson 5.5

you are almost surely not as mechanically dense as I am, but maybe the float is not set properly?

I wouldn't be so sure. Definitely going to check this today as well.

imho

weak sparks or inverted floats are not explaining why this engine is not pulling enough air/fuel from the carb face. air anyway !

without sufficient fuel and oxygen being pulled in to fill the chambers everything becomes a second priority
and to get fuel inside enough air must fill its lungs first !

works like a canon.... powder first... compress everything then.... light the fuse

I totally agree with you. I'm just trying to make sure I haven't missed any little things along the way.

It looks like I've been using a neon spark tester. It's not adjustable and it has a little bulb in it which I'm pretty sure has no filament and now that I think about how something like that would work (energy from the ignition discharging through neon gas) it makes sense to me why the color is off. So for the time being, I'm going to assume the ignition system is nominal and I'm going to focus on the air/fuel delivery problem.

I will disassemble the carburetor and intake manifold today and recheck everything. I'm going to pay close attention to the modifications I did for the fuel pump, the reeds and the orientation of the carburetor components.

 

[OptsyEagle]

Re: 1955 Johnson 5.5

Yeah, I thought we were talking about the color of the spark on the actual spark plug, not the color of the neon tester. In any event, it is best to not rely on colors, only gaps. This motor should put out voltage where a spark can jump a gap of 1/4 inch at a minimum. If it doesn't, then you are going to have electrical issues and if it does you should be OK as long as the timing is right.

If you don't have a proper spark tester, they are very easy to make. Leeroy's design is what I use and it works great. Just adjust the bolt to make a gap between the bolt and the upper metal plate of approximately 1/4 inch and look for a spark.

 

[derrTderr]

Re: 1955 Johnson 5.5

So I removed the carburetor and intake manifold today. I faced the mating surface of the intake manifold and checked the reeds, they are not stuck.

Then I started to rebuild the carburetor again. For some reason I thought it would be a good idea to try and remove the plates for the throttle and choke and ended up shearing off the head of the throttle plate. It is a tiny little screw and I had to drill it out. So now I have a hole that is a little off center.

I have no idea what that part number is. How difficult would it be to locate a replacement pin? Alternatively, how much of a deal is an inexact hole going to be?