59 Johnson CD-16 5.5 hp...NEED HELP

[DaffyJeffy]

Hi everyone. I really need some help here...

I did a complete restoration on my wife's grandfather's 1959 Johnson CD-16 5.5 hp. It was a labor of love so to speak, It had sat for a while and had poor compression when I got it so I decided to do a complete tear-down and rebuild. This project turned into a bit of a money-pit because I've had to buy so many parts. I also have a ridiculous amount of time invested in it at this point.

The 2-line tank was junk so I decided to replace it with a fuel pump as I've seen/read so many people do. Yesterday was my first day in the test tank and it didn't go well let's just say. Basically I could get it running...very poorly. It wouldn't come up to speed...then it would surge and die. I could keep it alive a bit by pumping the primer bulb but it ran like complete crap. It seemed way rich as the test tank was soon filled with an oily, carbony mess and my nice, freshly-painted new motor was all covered in soot. Yuck. It's like it was getting too rich a mixture and then air (when it surged) and then it would stall.

I used the conversion method where you jam a vacuum cap in one of the holes (removing the check valve) and use the port on that manifold for the "pulse". I've read on here that the pulse line has to be really short. Mine might be too long?

Or maybe I just have my lines plumbed wrong. Here's how I have it set up: Gas in from tank to glass filter bowl, out of filter bowl to the intake of the fuel pump, then out of the fuel pump to the carburetor. Again, the pulse is from the manifold covering the reed plate. Are my lines just too long?

Thanks in advance to anyone who can help me. I'm lost because I've literally rebuilt everything on this motor and therefore it could be anything...although I was very careful and this isn't my first rodeo (I've rebuilt more carburetors than I can count).

Also, if anybody is interested, here is what I've done to it: Carburetor rebuild with new float. Honed cylinders (after making sure everything met tolerance), new rings, new rods, all new gaskets, new thermostat, all new lower unit seals, impeller...she got the works...and new paint.

 

[DaffyJeffy]

Here is a pic

 

[F_R]

Well the pulse line is a bit long. But I'm not a good judge of that, since I'm not a big fan of that conversion. But done correctly it should work.

I'd prefer to put the filter between the pump & carb, to eliminate any possibility of sucking air through a minor leak. But it should work either way-----or you really don't even need the filter. There is a filter screen in the tank and another in the fuel pump cover,

There will always be gunk and goo in a barrel. That's just the way it is. However, if the motor is not burning the fuel cleanly the goo gets worse. Leave the hose overflowing in the barrel as a "skimmer"

 

[racerone]

As built the line from the reed plate is to pressurize the tank.----It is NOT a pulse line to run a pump.-----What changes did you do , if any to make that a pulse line ?

 

[Crosbyman]

racerone.. the pressure nipple becomes.. a pulse nipple if the check valse is removed and one channel blocked

good utube film on this and it works very well

https://www.youtube.com/watch?v=FtG4M7ye1N8

ive done a 5.5 i removed the check valve and sealed one air channel like the utube film

motor runs great never considered vacum hose length i doubt it is the issue here

oily mush in the tank is normal

pumping the bulb and dying anyway may point to flooding.... after an initial starving check all fuel routing and fuel flow

inlet needle & float adjusted ?? did you do a blow test on the carb (no air in when upside down)

blow fresh air on the motor with a fan to push away the exhaust fumes give it good air

btw how is the compression ???

 

[RCO]

Is there fuel in the pulse line? The last couple of those fuel pumps I got were junk, and would leak into the pulse chamber . Hook your fuel line from the tank directly to the carb and keep pumping the bulb . If it runs ok something is amiss with your pump conversion .

 

[DaffyJeffy]

All good questions Crosbyman. And yikes, I just plugged in my compression gauge and only got 65lbs in each jug! Do you think this could be because the rings are new and haven't "seated" properly yet? God I hope so because if not...well then I just don't know. I carefully installed new rings and gapped them properly. I checked each cylinder with a bore gauge for diameter, roundness, and tapper - everything is well within tolerance. I also carefully installed a new head gasket and torqued each bolt to spec. I suppose I could have screwed something up....but , man, I was SO careful. Ugh...this sucks.

 

[DaffyJeffy]

Hummm, I also honed the cylinders...perhaps the compression will increase after the motor runs a while and things seat properly?

 

[flyingscott]

I am curious what kind of compression #s were you expecting. 65 is good for that motor after break in you might see 70-75

 

[DaffyJeffy]

Oh...hum, well when I got it the was low 80s in one jug low 70s in other...I have it written down somewhere. I was thinking "good compression" was mid 80s - 90psi.

 

[Crosbyman]

well at this point I think the motor should run ... my 9.5s are 65-70 and run ok none of my oldies have 80-90 but all work fine ... maybe they are not lions but they run and troll all day

personally I think it is still a fuel issue ...are you needles adjusted per spec to start with ie. 1.5 turns out from seated etc...

did you blow test the carb for proper inlet needle function is float adjusted level to body


try to warm up the engine by puffing some fuel in the carb face just as it begins to die off

btw did you clean out the low speed chamber under the top plug ... it needs that fuel to idle


p.s. read up on the aomci 1952 3hp carb adjustment post

 

[oldboat1]

^^+1.

Additionally, the sintered filter and assembly could be an issue. Filter might be partially blocked, or the bowl gasket might be leaking. Might pull out the filter, check the gasket and reassemble -- then test run. (You might use a fingertip and apply some OMC gasket sealer or similar.)

 

[DaffyJeffy]

Thanks for the help guys I appreciate it so much. Let's answer your questions first:

1) I did properly adjust the float and I assume I did a blow test but can't really remember because it was like a year ago when I rebuilt the carb. But when I rebuild a carburetor, I'm very careful. Possible I screwed it up somehow but I want to explore other issues before I tear it down again.

2) Yes I did clean out the low speed chamber under the top plug (and resealed with new cap and permatex).

3) The gas filter does have a new rubber seal installed, but I removed the filter anyway to eliminate that variable.

So today I reconfigured the lines. I got rid of the filter altogether, and ran a much shorter pulse line. The pulse line was dry inside so that would indicate the fuel pump isn't leaking through.

One thing I noticed in my literature on this motor is that the initial carburetor setting vary depending on what you read. I decided to go with the official Johnson service manual settings: Low speed 1-1/4 turn, and high-speed 1/2 turn. Yesterday I had them set at; low speed 1.5 turns, high speed 2 turns (I got that info from the carb rebuild kit).

To be honest, I don't really know what I'm supposed to do with these needles. I can keep it running at mid rpm for a while but it's not like I can idle it down and make that adjustment and then got WOT and make that adjustment as it just won't stay running. They are still set at the Johnson recommendation for initial set-up - not sure where to go from there.

Today it ran better...kind of. Still not working right. I can get it to run rough at mid-throttle and any attempt to speed up or slow down results in a stall. If I just maintain at mid-rpm I can cheat and kind of keep it running by squeezing the primer bulb, but eventually it will surge to high rpm and die. It's like there isn't enough "cushion" in the float bowl to change speed...or the fuel pump isn't working right. I'm wondering if I should just replace the fuel pump to eliminate that variable.

 

[Crosbyman]

the bible book .. hopefully you have it... describes carb adjustments your CD is pretty much unchanged from older CD

http://162.144.28.33/lib/johnson/man...64johnson.html

http://162.144.28.33/lib/johnson/man...owner.html#/14

basically adjust the high side after warm up by tweeking 1/8 turns and waiting for changes in rpm etc.. then adjust the low side



possible you have bad pump ....hand pumping should prove that but if it dies while hand pumping it is drowning or starving

have tyou check the tank fuel pick-up or tried a new hose ....btw try running it with the fuel tank cap off maybe your tank is not venting

that carb may need a look into ....

 

[racerone]

Yes I know that the rubber check valve hast be removed to make it a pulse fitting !

 

[oldboat1]

probably know this -- but have to adjust the needles when the motor is warmed up and running. Adjust leaner (clockwise) until the motor sneezes (kind of like a miss) or stalls, then turn 1/8 or 1/4 turn richer (c. clockwise). On my motors, mostly '57s, the final settings are typically around 1/2 to 3/4 open for the h.s. needle, and approx. 1 turn for the l.s. needle.

Final h.s. setting is done on the boat around WOT. After h.s. setting, return to idle and tweak the l.s. needle as needed.

I believe your '59 should use a 24:1 gas/oil ratio.

 

[DaffyJeffy]

Thanks Croz! I did in fact take the gas tank apart just in case. I have a line running right into the gas now to eliminate that variable. Could there be an air leak in the line or primer bulb? I don't see any indication of a leak.

I just went out and ran it again. When it gets into the higher RPMs (right before it'll surge and die) I noticed gas coming out of the little bronze vent thingy on the fuel pump (What the green arrow is pointing to in this pic). What's the deal with that? I'm really thinking I should throw down for a new fuel pump...maybe try the more expensive Mukini one this time.

I like the idea of running a line directly to the carb and feeding it with the primer bulb. I want to try that too. Basically, if I'm pumping the bulb too fast it'll just overflow the bowl of the carb correct?

 

[DaffyJeffy]

And thanks Oldboat. When I get it to that point I'll do this! Just can't keep'er runnin' now.

 

[Crosbyman]

if you get gas out the brass screen I would say the pump is shot my understanding of that screen is that it is just an air vent allowing the diaphragm to pulse up and down


the inner diaphragm may be leaky


btw my Briggs Stratton indentical pump to yours says.... Mikuni (molded) on the back plate they are not expensive

 

[DaffyJeffy]

I'm going to order a new pump as the next step before I go monkeying around too much more with it. I'd like to eliminate that variable. I think my pump was the Oregon brand (the company that makes pretty good chainsaw stuff).

Your guidance through this has been extraordinarily helpful. I'll give and update in a few days.

Jeff