1980 15 hp idle....not

[hairtrigger]

This is a 1980 15 hp Evinrude that runs strong above idle.


I have had the carb apart and the idle circuit is clean (spotless)

When I come down to idle the engine loads up and smokes bad then slowly
grinds to a halt. I have to open the throttle to get it started and it starts easy.

I can find a place that it will run slower but to stay there I must close the low speed adjustment off. If i open it, even just a little, will load up and stall.

I seems to me it never stops getting gas from the main jet. I have the float (cork) adjusted level inverted. The float does not seem saturated if it was that would raise the bowl level and make it run rich ....maybe

I am a musky fisher and troll a bunch so I need this to idle smooth.


Any ideas?

GR

[Joe Reeves]

Assuming that you do have the high speed jet screwed in securely and a nylon gasket installed on the float needle valve............

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

(Fuel Pump Diaphragm Test)
(Two Hose Type Only)
(J. Reeves)

Note: This pertains only to the regular Two Hose type fuel pumps.

Leave the hoses attached to the fuel pump. Remove only the two screws that attach the fuel pump to the powerhead. Re-insert those two screws and install a nut to each of them so that the fuel pump is securely clamped together. With the fuel line attached to the engine, pump the primer bulb while observing the pressure/vacuum operating hole on the back side of the fuel pump. Should any fuel leak out that hole, the diaphragm is faulty.

If the diaphragm is faulty, the fuel pump will require rebuilding or replacing. Note that repair kits are not available for all fuel pumps, in which case replacing the pump would be necessary.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:
joe_omc32 | eBay

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[hairtrigger]

I just bent the float not once but now 3 times now it's at an extreme angle wile trying the carb each time ....... same


The fuel pump is new but I will try the test tomorrow

I wonder if the throttle plate could be on upside down? I did not have it off but someone else could have. ???

Really grasping at straws here

It has a new rubber tipped float needle I just ordered a new float so everything in side will be new.

Yes washer is under the main jet.

GR

[Joe Reeves]

It seems that you're overlooking something within the carburetor if the fuel pump is new. You're describing a flooding carburetor.

It's quite easy to adjust the float to be as I describe it in my previous post... I can't comprehend why you would be having a problem with it.

You don't by any chance have the float upside down??

[hairtrigger]

The float has a cut out to go around one of the galley ways so you could not get it wrong.

Things are looking better today I just got back from the local flea market where
I picked up two river anchors like new for $5 for the pair....now I need to
get the motor running

I will look at the fuel pump today. This is the second new pump the first one caused an opposite problem it would quit pumping at 1/2 throttle and the motor would just quit. As long as I would run at 1/2 or above it would go all day. Or squeeze the bulb to keep going slow.


GR

[hairtrigger]

I finally got to the fuel pump test, and no gas came out of the hole.

You are right, the carb is some how flooding. I can not see for the life of me how.

I have worked on 2 cycle engines all of my life. They are pretty simple. Raced go-karts when I was a kid. Bought my first Law Boy in 1966 to make money mowing lawns. on the weekends. (Still have it, It's a little tired but does still run)
I mow now with a 1980 electric start bagger Law Boy that I rebuilt last winter.
I have owned a 4hp 6hp 35hp and a 65hp Johnsons The 4hp was locked up and in a trash bin. I rebuilt it and it still runs fine. The 35hp got a hole in the head gasket between the cylinders (in Canada) Repaired it there.

So I didn't just leave the farm. That is why I came here. I am baffled
This is a really simple carburetor. I did replace the float needle before all this and that may be the trouble (First new fuel pump being bad.) I have a new needle and seat on the way along with a new float to replace the old cork one. The old cork float would have been trouble down the road.

When the parts arrive I will report back

Thanks

GR

[Joe Reeves]

A$$uming the float needle valve is in good condition and the float is installed right side up... set the float as follows.

********************
(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

The only other situation that will cause the carburetor to flood is if the float chamber vent that it located in the upper body is clogged..... and yes I know that it's a hellava job to loacate. Ants build nests there, bees clog it up with God knows what... it happens.

[hairtrigger]

Well ......No improvement

New float and new needle

I have to close the low speed adjustment and it still runs rich. If I keep it near idle speed it will load up and slowly grind to a stop.

Yes the bowl vent is open. Yes the float is set right

Now this is interesting. while it was running well above idle I place a finger over the vent hole and slowly the engine started to clean up and run faster. The smoking stopped and finally it was running faster than I wanted it to and I had to reduce the throttle with the twist handle. ???? I tried this again and again each time with the same result. The engine would lean out and run faster and faster.

Some how fuel is getting past something or through something.

I did learn a new skill, I learned to put the rope return spring back into the bell that held it only took about an hour. I got pretty greasy

Does anyone know how the throttle plate holes go, top or bottom mine are at the bottom. Is that right??

I am baffled, so simple, pulling my hair out.

Once more I will remove the carb a look for something.

GR

[hairtrigger]

I found some pictures of the carb and the throttle plate is in the right way. So much for that thought.

GR

[hairtrigger]

Well I temporarily solved this problem I bought a 9.9 today that will get me fishing a gain.

It is a long shaft and I need a short so I will look around for the parts to change it. In the mean time I can still fish with it being long

It is also missing a "clamp" that holds down the throttle cable "ball" but I can make one. It runs great and idles smooth.

As to the 15hp and the flooding carb I want to try not using the fuel pump, maybe just maybe the after market pump has to much pressure and is over coming the float needle. I know if I squeeze hard on the primer bulb I can do that. Test this week.

Running out of ideas

And it looks like everyone else has too.

GR

[Joe Reeves]

As to the 15hp and the flooding carb I want to try not using the fuel pump, maybe just maybe the after market pump has to much pressure and is over coming the float needle. I know if I squeeze hard on the primer bulb I can do that. Test this week.

No you can not! When everything is as it should be, fuel in the pump and carburetor with the primer bulb being pumped up hard... you could stand on that bulb and the float needle valve would stay shut.

I hope your second engine works out for you.

[hairtrigger]

Don't want to dispute you Joe but I seem to remember squeezing the bulb hard and making the engine studder. You are probably right but I want to try it anyway.

Seems I am running out of things to shoot at.

I was going to look for the parts to convert this 9.9 to a short shaft but I decided to just make a jack plate. If I can get the 15 running right I would sell the 9.9.


Running around in circles

GR

[Joe Reeves]

Don't want to dispute you Joe but I seem to remember squeezing the bulb hard and making the engine studder. You are probably right but I want to try it anyway.GR

That's okay.... what I am getting at is that if you can squeeze that fuel primer bulb and cause the engine to load up... something is wrong.

[hairtrigger]

Joe is there an email address for you ? I need a small part for the 9.9

[hairtrigger]

My email is gr49(at)comcast.net