1970 johnson 40 hp dieing after a few minutes of running.

[kyle99]

Hi, everyone. Ok so I have a 1970 Johnson 40hp m# 40EL70A that came on a boat I bought for 100$ after putting about 200 into the motor including the battery I finally got it running. (carb, breakers, plugs, and condensers. The motor was amazing condition). I don't have a barrel to test the motor in so I took it to a boat ramp and got it running with a little thicker than 50:1 oil and sea foam. It kept running really rough but cleared up after maybe a minute but I couldn't get it to idle for very long. It would still spit and shudder at 1/4 throttle but finally cleared up as well just by running it some more. now for the part that lost me. I could have it running for a little bit or just varying the throttle and in about 5 mins or so and it will just fall on its face just slowly die. Let it sit for maybe a minute or two and it will start up. I noticed that the carb was dripping gas out of the intake of the carb. Now out of the fuel system I haven't changed the fuel lines because they are still in good condition. I also haven't changed the fuel pump but it does pump.

 

[jimmbo]

When you had the carb apart, did you remove all the little disk plugs and clean under them, and replace with new plugs? Is the float in good condition and set correctly? Idle mix adjustment? Link and sync check/adjustment?
Do you have a service manual for this engine?

 

[oldboat1]

Might be too rich. Run 50:1 with good 2-cycle, and drop the Seafoam. May have to change out fuel lines, and flush the tank if stuff was loosened up. Idle mix is the air/fuel mix (carb), as opposed to the fuel ratio. Try for a leaner setting there too.

 

[kyle99]

When you had the carb apart, did you remove all the little disk plugs and clean under them, and replace with new plugs? Is the float in good condition and set correctly? Idle mix adjustment? Link and sync check/adjustment?
Do you have a service manual for this engine?

Little disksplugs? New plugs. The float is made of cork and I cleaned it with gas to get all the black funk off it and still floated and I did adjust the float to how the manual said to. The motor is a single carb so don?t need to sync them.

 

[kyle99]

Might be too rich. Run 50:1 with good 2-cycle, and drop the Seafoam. May have to change out fuel lines, and flush the tank if stuff was loosened up. Idle mix is the air/fuel mix (carb), as opposed to the fuel ratio. Try for a leaner setting there too.

I made it richer than needed due to how long it has sat. I flushed the tank before I did any thing because it smelled like pickles so wasn?t taking a chance with any of that. The idle mix I set back to where it was before I took it befor (1 1/8 turns out from all the way in)

 

[kyle99]

Thank you guys for replying tho!

 

[RCO]

Link and sync is referring to the adjustment between the carb roller and the ignition cam. If you are leaking fuel from the carb, something is not right with it. Is the vent circuit in the carb clear, replaced needle and seat, and cleaned under the aluminum plugs?

 

[jimmbo]

Core plugs may have been a better name. They cover access points on the carb. Carb Overhaul Kits have replacements so as to encourage removal to clean inaccessible areas of the carb circuits.
Cork floats are notorious for loosing their buoyancy and should be replaced. A heavy float, even if perfectly set, will raise the fuel level too high, with resulting flooding

 

[kyle99]

Link and sync is referring to the adjustment between the carb roller and the ignition cam. If you are leaking fuel from the carb, something is not right with it. Is the vent circuit in the carb clear, replaced needle and seat, and cleaned under the aluminum plugs?

I will have to look up how to link and sync it because I did not do that nor did I clean the under plugs. I don?t know how your supposed to take them out or how to put them back in and I would rather be save than sorry and just let it sit in Chem dip for a day then screw up the carb.

 

[kyle99]

Core plugs may have been a better name. They cover access points on the carb. Carb Overhaul Kits have replacements so as to encourage removal to clean inaccessible areas of the carb circuits.
Cork floats are notorious for loosing their buoyancy and should be replaced. A heavy float, even if perfectly set, will raise the fuel level too high, with resulting flooding

Oh wow, I didn?t know they did that will be going to the store to get a new float tomorrow morning and replacing that.

 

[lindy46]

I will have to look up how to link and sync it because I did not do that nor did I clean the under plugs. I don’t know how your supposed to take them out or how to put them back in and I would rather be save than sorry and just let it sit in Chem dip for a day then screw up the carb.

To remove plug, I drill a small hole through the plug (careful not to hit the casting underneath) and pry it out with a small screwdriver. Then you can clean/inspect underneath. Check the orifice where the needle comes through - make sure it's not damaged from overtightening the needle.

 

[kyle99]

how do you reinstall them? also i have a short 20 second video of the motor running from the other day and i know it won't help much. but idk how to post it here. also i will get longer videos to show what exactly happens. but i will be messing with the it on the things y'all have told me to check.

 

[kyle99]

https://instagram.com/p/BY9m3E_HSTWkP0J-AxggAGPGC9Xnauks7t9t0E0/

Here is the video

 

[kyle99]

Ok guy I?ve messed around with the carb and this is what I have done.
1. In the disasembly (the first time) of the carb the seat of the needle had a plastic washer but no gasket under it. So in the rebuild I only put the gasket no washer so I tested it and then I posted on here about it. Well after talking to y?all I took it apart agin put the washer back in with the gasket. And it seems to run better ish (with muffs) but still misses and does then it?s a pain in the bit to get running again.
2. On the L.S.A . I took the needle completely out and put new gaskets in (I didn?t on the first rebuild). Then set it back to where it was before.

Would pictures of the spark plug help? I have the j4c champions.

 

[kyle99]

No Title

Something else I?d like to ad is that when I?m priming my system with fuel i can continuely pump it and it will eventually pore out of a vent on the front of the carb.

 

[kyle99]

No Title

The small hole above the intake is the vent I?m talking about. (This is before I cleaned it)

 

[lindy46]

If gas is running out, the float is not installed/adjusted properly.