1992 9.9 E10RELENA high speed issues

gooden123

Seaman Apprentice
Joined
Feb 27, 2022
Messages
34
I'm a marine mechanic but not familiar with small outboards. This is mine and has ran perfect since February up till 2 weeks ago. I use it several times/week in all conditions. I fished in heavy rain and right away after starting it wouldn't go over 3000. And hasn't since, unless I do the lean death run (unclip fuel line. It takes off before stalling). What would cause the condensation pictured? It happens within minutes of running. Head is warming up to temp and no condensation on the powerhead. Just the carb and close to it.

I've tried
-Several new plugs (L77JC4 .040 and QL82C .030).
-New gas/oil to make sure that's good. No water evidence found.
-individually disconnecting each plug wire. Big difference each cylinder so suspect firing is OK but not eliminating that it's sparking right.
-running with cowl and air silencer off to try to stave off the condensation. No difference.

Mostly just asking a reason for heavy condensation that fast besides humidity.20220521_051330.jpg Or if this is normal on small engines?
 

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,442
no expert on condensation but much like friction alchol isused to "cool down" a hot kid's fever, fuel in vapor format also cools things down as the liquid form becomes vapours.

One question comes up of course...... does that model all do this or just yours. ? and if so is this a new problem ? .

I doubt plug types have anything to do with this.

I see what looks like a lot of plastics which will not share or absorb all that heat produce & transferred to the carb body by the powerhead leaving the plastics to be continously cooled down by the incoming fuel and condensate ....yes....the ambient humidity.


here is an article on carb icing......but you are just ...wetting same principle I guess
 
Last edited:

gooden123

Seaman Apprentice
Joined
Feb 27, 2022
Messages
34
Thanks for the reply. I guess the main part of my wonder is if it just is normal with these engines in relatively humid conditions. I wouldn't know because my cowl is always on since this is the first issue I've had with it. I'm leaning towards a float issue. I rebuilt the carb recently and it has been fine on 10+ trips since. My dealer got me a Sierra carb kit and the float seemed flimsy. Going to rebuild it again with an OEM kit and if nothing else, maybe I'll solve the issue "accidentally" in doing so. I'm also going to do a link and sync. There isn't much to this thing as I'm sure you know
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,825
Normal for that area to be colder with condensation on it !!!-----Is there a working thermostat installed in this motor?-----Does the motor run / idle at about 140 F degrees ?
 

kbait

Commander
Joined
Nov 13, 2007
Messages
2,462
Sounds like carbs flooding under normal conditions.
When you pull the fuel line, when it starts to run out of gas it runs normally. Check carb especially float valve
 

gooden123

Seaman Apprentice
Joined
Feb 27, 2022
Messages
34
Normal for that area to be colder with condensation on it !!!-----Is there a working thermostat installed in this motor?-----Does the motor run / idle at about 140 F degrees ?
Yup T-stat functions. I think I need to get an OEM carb kit and start there. Stinks I just rebuilt it a month ago but I didn't like that Sierra kit. It's a pain in the ass to get this carb off/on because its electric start plus the plastic bowl and plastic top plate make me nervous even touching the thing. Thanks for your help and I'll comment back when it's been resolved!
 

909

Chief Petty Officer
Joined
Jul 19, 2021
Messages
537
Had a similar issue with my 95 9.9
Ultrasonic bath solved it, with no kit.
 
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