Needing some help or advice on where to go with my 88 50hp Evinrude

[DaveAF]

I am needing some help on what I should do next. MY 1988 50hp VRO Evinrude (E50BECCS) has really got me guessing.

A marine tech told me that I needed a new or rebuilt power head because he had done all that he knew and the engine would idle. I got it home and the fuel hose from the tank was backwards. I fixed that and did a correct link and sync and it would idle, but really high. Also from time to time after I would throttle down from WOT back to nuetral the engine would just run on at a high rpm, probably around 5,000 rpm. Its like the engine is thrown in nuetral and not engaged to the prop.

Now last week on the way back from a short run fishing the the motor started to miss. So I decide to go through the carb again. I did that and I purchased two coil, but they were wrong. Put the carbs on and linked and synced, and after it would warm up it wouldnt move the boat on idle, it would die. So I decided to do some more troubleshooting. Yesterday I got compression reading:

Cold Top Cylinder 135
Bottom Cylinder 140

After 30 min idle and run
Top Cylinder 120
Bottom Cylinder 130

So the compression seems to be good. During that 30 min idle and run I got the engine finally to stay running when I had it in gear just above idle, (say cruising through a no wake zone). Still high when not in gear. When I thought that I was finished I decided to give it one more WOT run. I ran about 100yds and came down from WOT. The engine just continued to run on at about 5,000 rpms. I had to shut it down to get it to start, and that took a turn off, turn on, turn off of the key switch. Then it restarted and started back to the marina on WOT, and then the engine just went wooomp, like it would go above 2500 rpms. I think it was running on one cylinder. I docked it and was frustrated and went home.

I done some research in the OEM manual, and I am wondering where I should go from here. I am going to call the dealer today and see if they have the right coils and replace both coils.

But my questions is would the charge coil or sensor coil cause it to not idle properly or run on coming down from WOT. Or is the run on caused by my throttle cable not wanting to relax (probably not the right word)

It just seems funny that it wants to run on after WOT, and doesnt do this all the time. I know that the carb is clean a went through it again and it it spotless even in the small orifices. So the butterflies are not sticking.

Also if I have to remove the flywheel, what is the easiest way to loosen the large nut. I have a harmonic balance puller and plan on being real careful with the crank

thanks

 

[Boblester40]

Re: Needing some help or advice on where to go with my 88 50hp Evinrude

Dave...
Does not sound like you need a new power head your compression looks to be OK , a few starters

1./Have the the carbs had a service kit installed ? with new floats and needles, even if its clean the fuel may be two high or low in the bowl .
2./Intermitant missing sounds more like an ignition problem, if you get the flywheel off check the stator out with an multimeter using resistance on the charge coil side . also check from cracking or black goo weeping out anywhere
3./ Also check the ignition coils / sensor coil with the meter , you could have a faulty secondary winidng in the ignition coil again same resistance checks you can get the values form the cylmer manuals .
4./ Lastly check all the earthing points of the ignition system on the coils etc. a bad earth will cause the above . I had a 6hp give me the run around and it turned out to be the earthing point for the CDI .

Hope this helps
bob

 

[James R]

Re: Needing some help or advice on where to go with my 88 50hp Evinrude

Sounds like the motor needs the set up and components all going thru. A step by step checking is the only way to clean this up. Sounds like everybody is just stabbing at it.
I use my pneumatic impact gun to spin the Flywheel nuts off. There doesn't appear to be a better way. Use the puller but be sure to use the correct thread bolts. 3/8 inch threaded in should be enough. You will need to use the gun with the puller also. A small gun will probably not be of any use.