1984 Evinrude 50 HP Won't run at full power.

[Fatguy86]

The motor ran great last year until the lower unit hit something under water and I lost the prop, prop shaft, and the seals. I rebuilt the lower unit and tested the motor. It wouldn't hardly run at all so I checked both carburetors and the needles were bad so I rebuilt the carburetors. Next I cleaned the fuel pump. The motor still ran pretty bad so I checked forums for some information and found that the carbs have fixed needles, in order to adjust it the timing needs to be adjusted I tried adjusting the timing while the engine was in gear in the water but haven't gotten anywhere. When the motor is in gear even idling i have to continuously bump the choke button to keep it running. To get the motor running as high as I can get it while in gear I have to bump the choke button as fast as possible while taking the throttle up and down until the boat gains speed. Before the problems I could get the boat up to 24 MPH, now it will get to 12 MPH.

Both cylinders are firing and both carburetors are working but I can't find any information online to fix the problem.


Any information would be greatly appreciated. I will post images of the motor and timing linkage/carburetors soon.

 

[ondarvr]

If you need to use the choke (primer) then it's running lean, the carbs are either still dirty or not adjusted correctly.

 

[Fatguy86]

That is what I thought but the carbs can't be adjusted. they have fixed needles(the needles can't be adjusted, there aren't any rich/lean adjustments for slow or high speed) which is why the timing is the only adjustment. It makes no sense to me but all of the forums that I have checked say. The odd thing is, if I keep the engine choked it doesn't die or run better or worse, it only changes when i "bump" or tap the choke. I have rebuilt many Johnson and Evinrude motors ranging from 5 hp to 50 hp and ranging from 1956 to 1994 and never seen a motor like this one.

 

[ondarvr]

The carb floats can be adjusted and so can the linkage, if that doesn't do it then they're either dirty or there's an air leak.

A weak or failing fuel pump could also cause a similar problem. Bumping the primer could mean there's not enough fuel being delivered to flood the motor, only enough to make run better for second or so. Once the RPMs build up enough the pump may work better. Try squeezing the primer bulb while the this is happening.

 

[Fatguy86]

I cleaned and rebuilt the carbs so they aren't dirty but i'll pressure test the fuel system. Do you know or can you direct me to somewhere that can tell me how to properly adjust the linkage? I have tried to adjust the linkage and timing(the timing adjustment is part of the linkage adjustment). I have attached 2 pictures that I found online, I will attach pictures of my motor tomorrow. the image with the linkage shows where I have adjusted the linkage, I have also adjusted the throttle cable(not shown). The second image shows the carbs. The screws labeled #2 are drains for the bowls. The screws labeled #1 I have attempted to adjust but they didn't make any difference, when doing research on forums I got different information on what they are for. One site said that they were for idle adjustment and should be adjusted at 1 5/8 turns out to start with, then adjusted in small amounts from there. Another site said that they should be tightened firmly and not adjusted at all. I have tried both.

 

[juno pierrat]

sounds like the idle circuit is still dirty, did you remove the core plugs during cleaning?

 

[Fatguy86]

I really hate to sound stupid but with all of the information that I have read about the engine I haven't heard of an "Idle Circuit" and I'm not sure what the core plugs are. When I cleaned and rebuilt the carbs I completely disassembled them and cleaned all orifices and all parts the same way that I have done on my other 1958 and 1962 40 hp motors, of course these carbs are different but the process is still the same.
When the lower unit was damaged we didn't drain the carbs(didn't even think about it after we paddled 2 miles back to the dock). Could that cause a problem with the idle circuit? btw I have cleaned all of the fuel system that I thought could be causing the problem.

 

[ondarvr]

Years ago I had a 50 like yours but it was a few years older, the screws did adjust the idle mixture, I'm not sure if they changed to a non adjustable screw after that.

The 1 5/8 turns out is just a starting point, you can go either way from there to get it to run right. If those are adjustable, and they don't do anything when you turn them, then the carb is still dirty. You need to pull them out and clean it well.

 

[interalian]

If you back #1 screw out all the way, is it a needle or just a flat plug? Your answer is in there.

 

[racerone]

When a motor comes to a " dynamic halt " it is possible to shear the flywheel key and that throws out the timing.

 

[interalian]

When a motor comes to a " dynamic halt " it is possible to shear the flywheel key and that throws out the timing.

Because inertia.

 

[juno pierrat]

in your first pic, looking on top of top carb is a small disk, the core plug, under it are 2 or 3 very small holes that need to be clear, order a rebuild kit core plugs included, gaskets, floats. every so often carbs need rebuilding, instead of cleaning.
to get core plug out poke a small hole in it, pry it back and it pops off, poke small wire through holes, put new plug(dome up) in place, put a 1/4 ratchet extension on it and tap it , expanding the plug and staying in place

 

[Bosunsmate]

Id go with the flywheel key suggestion. Line up the flywheel tdc (0degrees- its written on the flywheel outer circle) with the arrow on the side of the top of the motor (its like a pointer) and check that the top cylinder is at top dead centre. Its a lot easier to do it that way than pulling the flywheel.

Ive the 1982 and that doesnt have anything adjustable in the carbs, its all fixed orifices and i suspect yours is the same

 

[juno pierrat]

go with flywheel check, the idle thing doesn't effect higher RPM's

 

[Fatguy86]

Thanks everyone for the replies
interalian I checked the #1 screw and it does not have a needle so that info was helpful

I checked the woodruff key for the flywheel and it had been damaged. Once I removed the flywheel I found a definite issue, the charge coil is basically broke. when the motor hit the rock I think the flywheel shifted just enough to clip the coil and broke the coil loose from the mount, it is still in one piece but is definitely damaged. I plan to replace the coil and woodruff key then give it a try.