Hello: I have a 96' or 97' 9.9hp long-shaft, 4 stroke Evinrude. Here's the problem...Motor will start cold after 5 or 6 pulls. It runs fine throughout the throttle-range. However, approximately 10-20 minutes of driving my 25' sailboat, the motor runs really rough, despite changing throttle/choke positions. If I remove the cover, the motor will recover and continue to then run. There's cool water shooting out the rubber hose on the back during the entire episode. I ran the motor and pulled the top cylinder plug off at what I assume to be the coil...it continued to run. I replaced it and then pulled the bottom cylinder's plug-wire off and the motor sputtered and quit. It seems to only do this with the cover on and almost always is remedied by quickly removing the cover and allowing air to circulate. Any help would be appreciated, thanks...Jim.
You probably have an exhaust leak at the power head , a little detective work will find it. However the latch might smuck the spark plug boot when cover both removed and replaced. The boot would wear away and jump a spark across to the latch and cause a miss...you might check to make sure that is not your problem...just a Thought
Thanks for the prompt reply. I would add this, however. Pulling the plug wire off of the one cylinder kills the engine even with the cover off (albeit with the engine still warm to hot). If it were an exhaust leak, wouldn't it still operate OK in light of having an ample supply of fresh air?
That is what made me think of the latch, check for wear on your plug boot. Also check compression and spark as explained here.
(Compression & Spark Test)
(J. Reeves)
1st - Regardless of what problem one might encounter, always start with the basic troubleshooting procedure. Check the compression which should be in the range of 100+ psi (somewhat less on the smaller hp engines) and even on all cylinders.
2nd - With the spark plugs removed, rig up some type of spark tester whereas you can set a gap to be jumped. On magneto ignition systems.... and also the Battery Capacitance Ignition system OMC engines from 1968 to 1972, set the gap to 1/4". On the solid state OMC ignition systems from 1973 to the present, set the gap to 7/16". The spark should jump the gap with a strong blue lightning like flame..... a real strong blue snap!
If there was no spark, on engines from 1973 up, disconnect the RED main electrical plug at the engine. Remove the s/plugs. crank the engine via the starter solenoid (jumper bat term to small 3/8" term nut, not the ground nut) and observe spark. If spark is now okay as stated above, the usual cause is a shorted ignition switch.
If the above checks out as it should, and the engine dies out when throttle is applied or won't idle, it is usually due to one or both of two things. The carburetors are fouled, in which case the cure would be to remove, clean, and rebuild them..... or the timer base under the flywheel is sticking which would result in a retarded spark. If the engine will not fire/start at all even though you have the proper spark and compression, it's usually due to fouled carburetors.
To check the timer base for sticking (Engine Not Running), spin the prop to align the shifter dog with forward gear and while doing so, put the engine into forward gear. Now, while watching the timer base, slowly apply throttle clear up to full throttle. The timer base should move smoothly all the way up against the black rubber cap that is atached to the end of the full advance spark setting screw. If the timer base sticks, find out why and correct that problem.
Usually any sticking of the timer base is caused by one of the four retaining clamps being slightly too tight. Putting a very thin washer under the clamp cures that problem. Some boaters use a thin screwdriver to bend the clamp upwards slightly but I prefer the thin washer. The sticking can also be caused by having a faulty stator start to melt down, resulting in a sticky substance dripping down on the timer base nylon retaining ring.
Thanks for the prompt reply. I would add this, however. Pulling the plug wire off of the one cylinder kills the engine even with the cover off (albeit with the engine still warm to hot). If it were an exhaust leak, wouldn't it still operate OK in light of having an ample supply of fresh air?
Well, you now have two issues. The first you know about, exhaust in the cover. The second is dropping a cylinder. The plug wire, that when removed, kills the motor is working. The other plug-cylinder is dead. Do a spark test and get some compression readings and report back.
Well, I've pulled the motor and have it at home. The model # is E10FEXEDR (a "high thrust" 9.9hp 4-stroke outboard). I hear it's easy to find an exhaust leak. Could someone please tell me how? The shifter-rod (my term) goes down vertically through a half-dollar-sized hole in the floor of the cowling and disappears into the lower parts of the motor. Is there supposed to be any type of boot, dam, etc. sealing that hole through which the rod descends? At the moment, the thin rod goes through the much larger, unsealed hole. Can exhaust rise through there? Thanks. Also, Is there any resource online that I can utilize to find a parts breakdown of this motor. Again, thanks...Jim
9.9hp Evinrude dies w/cover on
Linear Mode
