1976 Evinrude 9.9 runs poorly onced warmed up

[roncarter]

Gang,
I have a very odd problem. it must be odd since i cant find this exact problem in the FAQ's.

My 9.9 Evinrude 1976 was running poorly. When i started it up, it ran at idle and purred like a kitten for 5 minutes or so. Took off full speed with no problem. Once running about 5 minutes it began to stall ( like it was out of fuel). I throttled down to keep it running. I can throttle up slow and it will go. Throttle up fast it will stall out. Will start right back up on 1 pull. then the idle goes away - it spits and sputters every ten seconds and it seems to even backfire a bit - bubbles out the prop exhaust. I can work the choke a bit (pulling choke out 1/4 to 1/2 way) and it will run wide open but not like it should.


The above issue started last fall. So, i played with it over the winter - replaced the water impeller and put new seals in the lower unit.

I rebuilt the carb last night thinking that my old cork float was chewed up from the Ethanol gas. The varnish on the float was messed up but i found no debris, stickyness or rust in the bowl. Started up on the stand on the 2nd pull.
so, i put it back on the boat this morning and it started right up. Idled perfectly. Took off like she always did. Then it started to bog down again after 2 minutes of running. Ran it 1/4 choke to get home. Once back in the cove - it wont idle smooth again.

This seems to be a temp issue. The current water temp is around 58 degrees. When the motor is cold it runs - Warmed up it wont. So, my next thought is possibly water thermostat?

Any ideas would be a great help??? I have worked much on an outboard motor really but, know enough to be dangerous i guess.

 

[oldcatamount]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Sounds to me like it's dropping a piston after warm up. That's usually a sign of a weak ignition coil. Look at both coils for cracks or burn marks. Also look at the plug wires and make sure both plugs a clean and gapped right. It could be a fuel issue ie: weak fuel pump, tank not venting, dirty carb etc. but I'd look at the igniton coils first. A test would be to bring a timing light with you and when the motor stumbles, check both plug wires with the light.

 

[Bosunsmate]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Can you put your hand on the head for at least ten seconds when its warmed up?
Could be the thermostat and or water pump.
And definitely do the check for a weak ignition coil, take a spark tester out with you

 

[OptsyEagle]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

When it starts to die or sputter, try squeezing the primer bulb. If that revives it for any period of time then it is a fuel pumping issue, if it doesn't then you can rule fuel pumping out of your list of culprits.

You want to make sure the carb rich/lean adjust is set properly.

http://forums.iboats.com/engine-fre...sorted-carb-variations-joe-reeves-167352.html

Also, look to see that your timing advance is set right. When turning the throttle grip the indented arrow on the throttle cam should be in the center of the carb's roller just as the roller touches the cam.

I would also make sure that the fuel screen in the fuel pump is clean and that the 4 screws on the fuel pump are very snug.

 

[roncarter]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Thanks for the thinks to check.

The fuel is all good. fresh gas and oil. tank cleaned and the lines flushed. When it began dying out - the fuel bulb was still firm.
If i throttled down and 1/4 choked it - it would run OK. i could slowly take it back to full throttle. Also, i tried spraying carb cleaner into the carb while running it full speed. when it was sluggish - i sprayed in and it took off nice.

Will check the timing, i think i have a light down there at the lake? Dont use them old things much anymore.

As for getting hot - it doesnt seem to be getting hot but will check the head for the 10 second deal.

As for water - i have good water output at all times. But, this motor does not have the pee stream just the blow hole.

I set the rich/lean as follows - turned all the way in, turned out 1.5 turns. Doesnt seem to make a difference once warm. When i first start it up - it runs perfect.

 

[roncarter]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Sounds to me like it's dropping a piston after warm up. That's usually a sign of a weak ignition coil. Look at both coils for cracks or burn marks. Also look at the plug wires and make sure both plugs a clean and gapped right. It could be a fuel issue ie: weak fuel pump, tank not venting, dirty carb etc. but I'd look at the igniton coils first. A test would be to bring a timing light with you and when the motor stumbles, check both plug wires with the light.

I will look for instructions on how to check the timing.

 

[OptsyEagle]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Timing on these things is pretty much set by setting the ignition points to 0.020" and then ensuring your timing advance is set as I have indicated above.

Timing lights are good, but not necessary in my opinion, but if I owned one I would check it out.

 

[roncarter]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Timing on these things is pretty much set by setting the ignition points to 0.020" and then ensuring your timing advance is set as I have indicated above.

Timing lights are good, but not necessary in my opinion, but if I owned one I would check it out.

Will check the points. They havent been checked in probably 20 years....ha

 

[Daviet]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

When you had the carb apart did you check the high speed orifice in the bottom of the carb bowel to see if it was restricted or plugged?

 

[roncarter]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

When you had the carb apart did you check the high speed orifice in the bottom of the carb bowel to see if it was restricted or plugged?

I blew out all of the orifices in the carb when i had it apart. All looked good. Replaced everything that came in the OMC kit.

 

[roncarter]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Well, took the flywheel off this morning. My points are a little small. One is at .017 and the other at .018. Is that enough to cause my issue?
Coil and wires all look good.
Will set at .020 and give it a whirl.

 

[OptsyEagle]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

You will not notice much difference between 0.017" and 0.020".

The important thing here is to ensure the points are clean. I would file them very lightly with a points file and then blow with compressed air. I would then take a clean white business card and dip it in lacquer thinner and run it through each point and then blow with compressed air. You want to ensure no rust or oils are on those points.

Did you try squeezing the primer when it was about to die. I know you said it was still firm but did you try squeezing it. In other words did you try to manually pump the fuel to rule out a problem with your automatic pumping of fuel?

Did you look at the link and sync of the carb and did you set the rich/lean adjust properly? Is the fuel screen in the fuel pump clean and are all 4 screws on the fuel pump very snug to the engine.

Other then that is sounds like the carb is still dirty or the carb vent is clogged.

 

[roncarter]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Thanks for the response. I just set the points. Will clean them as you suggested as well.
As for squeezing the bulb, yes I did when it was stalling out. No change in the running.
After I clean the points, I will be putting it back in the water and giving it a run.
As for timing advance, I believe I am following what you are saying and the roller is hitting properly.

 

[roncarter]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Well, doing the same thing after cleaning and setting the points. Started up right away, I adjusted the rich/lean properly and it idles sweet. Then as I took off- it wanted to die after a couple minutes. Squeezed the bulb- no change. Back at idle- it sneezes them it settles back down and idles smooth.
But after a few minutes of running higher Rom's it will die. If I 1/4 to 1/2 choke it- it will run pretty well.

I am thinking carb still. Could it be condenser coils? Mine look good but they are original.

 

[OptsyEagle]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Sure sounds like the carb. In this case the high speed jet probably.

Are the two nuts holding the carb to the intake manifold good and tight? Can't have an air leak there or you will have the troubles you describe.

Also, I believe the little hole on the upper left side of the carb, beside the slow speed needle is the carb vent. Can you see if a little critter or something maybe crawled in there and died?

 

[racerone]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Run with a timing light and see if ignition breaks up.

 

[roncarter]

Re: 1976 Evinrude 9.9 runs poorly onced warmed up

Thanks for staying with me on this one guys. I will pull the carb back out and check it -especially the high speed jet and the vent.
If the problem persists, I will shoot it with a timing light. Done for the day- crappie are biting and I need to fill a bucket!