early 90's evinrude 20hp carb issue whipping my butt

[stingertrey]

Hey, guys. I havent been on here in ages but this place has always been my go to for issues I cant resolve.
Anyway, I have had an evinrude 20hp for quite a few years and its always ran well. I didnt run it for probably a year and a half. Throw some life in there mixed with deployments and it was neglected. Well... the last month I've replaced the water pump to make it pump, removed the carb and completely went through it. I took it to the river and it ran like a new motor. flash forward 2-3 weeks and I took it back to the river and it would not run well at idle and basically wouldnt go to higher rpm's.. it wouldnt die out it just stayed in a boggy state and wouldnt "take off" just perma bogs. During WOT input I can have the fuel line crimped like you would a water hose and it will TAKE OFF and run.. SO I say ok its flooding (needle valve not seating was my thought) this was all but confirmed when I got home and it sat for 2 hours or so and filled my cylinders with gas.

I took the carb apart and its spotless. float is adjusted to level as it should be.. and the needle valve and seat are both clean and brand new.. So I thought maybe a fluke.. made sure it was all clean by spraying and put it back together... continued trying to fill cylinders with gas if it sat out in the sun, took it to the river this morning and its the same thing.. boggy and only runs well with the fuel line crimped to limit fuel.. its also smoking like hell with a 50:1 mixture which makes me think its extremely rich fuel/air. I bought a new needle and seat on the way home from a boat shop so im probably gonna slap that in there. Is there anything Im missing here?

the only item in the carb that isnt new is the float.. Im going to replace that as well when I go back in. Its not hollow plastic style floats.. its almost foam feeling. but it doesnt seem to be saturating with fuel.. So I let it ride initially

 

[stingertrey]

sorry this was so long winded.. I wanted to give everyone the full timeline of my struggle

 

[racerone]

Check the fuel pump diaphragm.----I say that possibly it is ruptured.

 

[stingertrey]

I think I've got it figured out. Fairly certain my primer solenoid is staying energized. which is causing a straight stream of fuel from the fuel pump to be dumping into the back of the carb into the intake.. this would explain the rich air/fuel ratio and the fact that fuel has a clear path to fill the cylinders with fuel while it sits and heats up outside. Hopefully this helps someone else in the future.. bc it whipped me

 

[kbait]

If your tank is new, and puffs up like a balloon in the sun, and your primer leaks (or is set to manual prime), your diagnosis makes sense. Make sure red knob on primer is parallel to primer body (normal setting), and loosen cap so tank doesn’t build pressure..
Good luck!

 

[stingertrey]

ok updating this. Ran the motor again today.. the fuel draining into the block issue is fixed. Motor cranks and runs great, when I stab the throttle it jumps up like its gonna take off and plane and just stops. It will freeze there as if you left the throttle at 50%. I pulled the cowl on the water and confirmed the butterfly was opening 100% and it is.. I disconnected the temp switch, Tried pumping the bubble (it was remaining super tight), Tried crimping fuel line to see if it was getting too much fuel with no change. It just ran all day as if it was stuck at 50% throttle while I would have the throttle buried. This carb has been cleaned 5 times in the last month it feels like so I dont want to believe its a clogged main jet.. but not ruling it out.

Can spark plugs cause this? It doesnt seem to be losing fire.. even while its stuck at the 50% feeling while input is 100% throttle its running fine.. it just seems limited.

Also replaced the fuel pump yesterday with a brand new one bc I had it in the shop.

 

[Crosbyman]

did you do a blow test on the carb before reinstalling any chance the float snags on the gasket edges inside the carb.......


can u describe "cleaning the carb 5 times... exactly what did you do ?

did you clean out the jet orifices with a fine wire or monofilament followed by a blast of carb cleaner and air pressure ?

did you install the fine clip on the float to pull down the inlet needle when the float drops ?

 

[racerone]

Maybe a reed valve stuck open.----Or bottom crankshaft seal is bad ?----Any chance critters built a nest in the exhaust housing ?----They all need a home too.

 

[stingertrey]

Yes the clip is installed on the float.
I did do the blow test on the carb ensuring the float was sealing then opening
I've blown out all jets/orifices multiple times, I typically run some .020 safety wire through the jets as best I can then blast with compressed air. Also has all new fuel lines.

Im fixing to go outside and do a compression check and put my spark tester on it.

 

[stingertrey]

Maybe a reed valve stuck open.----Or bottom crankshaft seal is bad ?----Any chance critters built a nest in the exhaust housing ?----They all need a home too.

Is there anyway to verify a reed valve being stuck open without removing the starter/carb and intake?

 

[stingertrey]

Is there anyway to verify a reed valve being stuck open without removing the starter/carb and intake?

and exactly how does the bottom crank shaft seal cause this issue, Ive never heard of this so please teach me lol

As far as critters building something in the exhaust housing it would have to be fairly recent, When I first ran this motor after all the work performed in the original post it ran like brand new, then the primer choke bugged out on me, So I replaced that and the fuel pump yesterday thinking it would be back to that great running motor I always had. To now have this issue of being sluggish and not wanting to turn up hard under a load

 

[racerone]

Sorry----I can not see , hear or feel your motor.----I can only suggest simple things to check !

 

[Crosbyman]

a bad seal would allow air to infiltrate (get sucked in) the crankcase instead of precious fuel vapours being suctioned from the carb. less fuel .. less power

 

[RBoyd1971]

What do the spark plugs tell you? They should be a golden brown. Are they wet and oily or dry and clean. You should read them after running wide open, not idling in a barrel or on a hose.