9.9 Evinrude Issues

[txarmydude]

I have a 9.9 Evinrude on my 14' Jon Boat, and I have been having issues keeping it running. I just rebuilt the carb, and replaced the water pump and housing. It pumps water just fine when it runs.

When I hook it up to the muffs, it runs like a champ. It idles just fine, revs like it should and stays running. However, when I get it behind the boat on the river it will barely idle at all. It will intermittently run WOT, periodically losing power and dying at WOT. Then it will pick back up again, work for 5 minutes or so, then do it again.

This little motor is really making me nuts. It is kinda hard to start, on top of all these other issues. One other thing, how can you tell if the plugs are fouled? Aren't they supposed to have a little bit of oil on them on these 2 cycle motors?

Many thanks...

 

[cr2k]

Re: 9.9 Evinrude Issues

Pull a spark plug and rotate the crank by hand and have a look at the carbon on the piston.
You may also have carbon partially blocking the idle relief ports (high on the back of the leg).
Decarbonizing may be of some help.
Use the Champion plugs it calls for.

 

[raczekp1]

Re: 9.9 Evinrude Issues

post year of the motor-serial no can help(1974-1977 points ignition, 1977 and on CDI ignition with powerpack)

if you are sure the carb is ok and slow speed needle is set at +/- 1.5 turn out then

this symptoms may occure:
- when you run at 1 cylinder only, try to disconect coils and change coils places
-compresion is staring to dissapear(blown head gasket and warped the head surface)
-rings stick to rings grooves-sea foam can help
-you lower unit is bad, and under load on the lake something is blocking the drive shaft
Can you post video on you tube.com?

 

[jmendoza]

Re: 9.9 Evinrude Issues

Oily plugs means fouled plugs, so put in a new set and try again. Make sure tank vent is open, and tell us what the year model it is, or the model number off the tag on the bracket.

 

[txarmydude]

Re: 9.9 Evinrude Issues

Sorry, the motor is a 1996. The plugs are very oily, but they looked ok otherwise. I will get some new ones asap. I noticed that the plugs were in there kinda loose. Would that make it lose compression?

Thanks for all help!

 

[nwcove]

Re: 9.9 Evinrude Issues

loose plugs will cause compression issues!!! and ruin the threads in the head. id start your diagnosis with a compression test, then move to fuel ( if you have good spark). a bit of seafoam goes a long way if it is a carbon problem.

 

[JDusza]

Re: 9.9 Evinrude Issues

atxarmydude,
Ah, the psychiatry of Evinrude maintenance, ...
A little history may help, too. Is the engine new to you? Did it ever run well for you? Why did you rebuild the carb?
If you are afraid loose plugs are causing compression issues, this indicates to me you are not that familiar with the engine, it must be new to you.
Let's not go astray ....
It sounds like we have to diagnose between ignition and fuel. Compression sounds OK for you are able to run without major mechanical noises, etc. lol Check your compression to verify it is good, but I think we need to separate ignition from fuel delivery.
Do an air gap spark test. When satisfied spark is capable, get the muffs back on and using insulated pliers, pull each of the spark plug wires to verify running on both cylinders.
If compression is good, and your firing both cylinders, then back out on the water we go to pump the fuel bulb while running, etc...
J

p.s., sweet rig!

 

[txarmydude]

Re: 9.9 Evinrude Issues

The engine is a little new to me. It has a new water pump impeller and impeller housing installed a couple of weeks ago. When I first got this motor, it would only run if you kept pumping the fuel bulb. After the carb overhaul, this was not an issue. The fuel pump looks good. I can't see a bad spot/tear/hole in the bladder, so I'm pretty sure the fuel pump is all good.

I will replace the plugs and try running it and pulling off a plug wire at a time to see if only one cylinder is firing. If this turns out to need a new head gasket, it doesn't look that hard. It looks like the head would come straight out without that much headache. Anybody try it on one of these 9.9/15 horse 'Rudes???

 

[destroyer_85_golf]

Re: 9.9 Evinrude Issues

i had the same problem with the 15 hp evinrude that i use for frogging. my problem was the fuel pump.