# 1989 Evinrude 50hp



## kalninm (Jul 9, 2018)

So I've done a lot of little work on this motor, carb rebuild, spark plugs, fuel filter, water pump, new fuel line with primer ball, etc. However it's still acting up. It'll sit and idle in the driveway with muffs on at 1400rpm, but when in the water it tries to idle at 500 rpm and just dies out. I've increased the idle speed in the driveway three times and it still won't idle high enough in the water to keep running. However when I do get it to turn over if I get it into gear quick enough I can give it gas and then it'll stay going. When I try and actually go though, anything over 1/2 throttle, I get surges in power. there's no cut out at a certain rpm or anything like that it just gives me power and then loses it back and forth. Any thoughts here? Oh also while it idles it likes to backfire here and there which drops the rpms way down. I'm a little baffled, but I'm checking for air leaks this evening in the fuel line. Any other thoughts here?


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## Pappy (Jul 9, 2018)

That vintage engine is a bit of a pain to do a proper sync and link on. You may need to purchase a manual and go through it. 
Honestly it sounds to me like your idle circuits in the carburetors are not clean enough or not set right. 
Did you purchase new OEM kits? 
How are you raising the idle?....be specific on what adjustment you are changing. 
As far as the lean pop goes forget looking for an air leak in a fuel line. The issue is long after the fuel lines have delivered the fuel into the carburetor. 
A lean pop is just what it sounds like. To check a simple thing first, start the engine on a hose and let it warm (it is warming up to around 135f right?) don't guess.
After the engine is warm and exhibiting the lean pop simply pop the linkage off that connects the upper carb to the lower carb. If the pop stops you need to re-adjust. 
You should have mixture adjustments on those carbs.....what are they set at?


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## kalninm (Jul 10, 2018)

We attempted to do a link and sync and the motor would not even run after we did that. So honestly we just played around with different adjustments trying to get it back to running and went from there. Yes all the parts we replaced were OEM including the carb rebuild kits and thermostat. Maybe I'll try and mess around with that tomorrow, tonight i get to do 5200 on the keel. Yippie! lol


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## Pappy (Jul 11, 2018)

When you answer the specific questions and try what is suggested let us know.


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## kalninm (Jul 11, 2018)

will do


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## kalninm (Jul 11, 2018)

Alright so got some time this evening and played around with it. I'm able to adjust the idle by moving the throttle roller. Found the engine block and water coming out is ice cold even after running for 15-20 minutes. Also, I did replace the thermostat at the beginning of the year. After adjusting the throttle roller we were able to get it to idle very smooth at 1000rpm on muffs. Played with the lean/rich adjustment for idle speed and found the engine did not respond until the screw was completely in and the engine died. Also, when adjusting the throttle roller to increase rpms, around 1500rpms it begins to pop like described before. thoughts?
Thanks


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## Pappy (Jul 12, 2018)

Thoughts...yes.
You do not adjust the idle RPM with the throttle roller. 
The engine is designed to idle with the throttle blades completely closed. There are calibrated holes in the throttle blades to allow the correct amount of air past the blades to achieve a proper idle RPM +-. 
Idle RPM is adjusted by idle ignition timing and carburetor mixture. Still seems your idle circuits are not flowing fuel yet. Those adjustments on that particular engine make a huge difference with 1/8 turn increments. Try it again and see. Also do like I asked you do to and pop the linkage between the upper and lower throttle blade loose while the engine is running and see what audible difference that makes. If it makes one it needs to be adjusted.


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## kalninm (Jul 12, 2018)

Alright as an update....
Not going to get to run it tonight but more notes from yesterday.
I did disconnect the linkage to test that and forgot to mention it last night. When I do this the motor dies immediately. Also will not start with the blades closed. When making adjustments to the idle jets there is no noticeable difference until they are all the way closed and then the motor just dies. Lastly, I did mention it never seems to heat up, the block is ice cold even after running for 20 minutes or more and so is the water the motor is peeing out. The reason we adjusted the idle speed with the throttle roller was because it would not start with it in the idle position. 
Obviously I'm missing something because while it's running and we got it to run a little smoother last night it is not running like it was designed to. However, I'm still lost as to why. When we rebuilt the carbs this winter they were perfectly clean, jets included so I would assume they are working as they should, but the adjustments aren't doing anything so I'm probably wrong lol. Sorry to ramble just trying to give you the best idea of what we've tried with it thus far.


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## Pappy (Jul 12, 2018)

You may have a fuel pump leaking into the crankcase. Pull the pump without disconnecting any lines other than the one that goes to the crankcase if so equipped. Pump the primer bulb (not too hard) and see if fuel comes out at the crankcase port. If so that is where the excess fuel is coming from.
If not......I would start from scratch on the carbs. See if you have installed a float upside down, etc.


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## kalninm (Jul 12, 2018)

Sounds like a plan, probably get around to it next week after work for a night or two. I'll keep it posted with what I find. Thanks for the help!


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