Help with float adjustment on 1974-1979 Johnson Evinrude 9.9hp

After a carb rebuilt, I used a 79 Evinrude 9.9hp and it ran good, except for one small issue: after a full throttle run, when slowing down, the engine would stall. It would start right back up and run as fine as before, until the next full throttle run and stall again when slowing down (sometimes with erratic reving prior to the stall). A user suggested adjusting the slow speed needle richer, which I did, but it didn't fix the issue. Then a couple of days ago, it got worse: after stalling, it began to show signs of difficulty restarting, with a crappy idle and would even stall after engaging forward gear. As it felt like a fuel intake issue, I decided to take the carb apart again, and I noticed the float way up, as opposed to parallel to the carb body as I read it should be. So all excited as I was, thinking I had found the cause of my problem, I bend the metal tab attaching the float to the carb slightly, so as to have it perfectly parallel to the carb, and put the thing back together after cleaning all orifices and high speed jet. Then, no start. Zero, zilch, nada. As in no fuel is able to make it to the carb tank....

So my question to the experts is this: When bending the metal tab of the float, don't we affect the way the tab is pushing down on the needle? And if so, is there a way of testing (other than by making sure we have a "parallel-to-the-carb" float)??? Because I don't see the point of a parallel float if by bending the metal tab to achieve parallelism, I shut the fuel flow off.....

Thanks as always for all the knowledgeable input!

JD,

When you adjusted the float level (perspective with the carb upside-down) did you support the float arm WHILE you did the bending so that the needle was not forced into the seat? If you didn't isolate the needle while bending you may have damaged it. You'd need some magnification to properly inspect the float needle.

Next, did you also adjust the DOWN travel of the float (perspective carb rightside-up)? You'll need access to a Service Manual to get the correct distance.

Also, check for fuel system air leaks: pull the fuel input line to the carb, pinch off the end of this hose while pumping the primer bulb. See any leaks from the Quick Disconnect all the way to that line that feeds the carb. This will check for any leaks from the QD all the way through the fuel pump.

Keep in mind that adjusting the float level determines how much fuel enters the carb bowl until the float shuts the flow off until some of the fuel is used. Once some is used, the float will "drop", thus allowing more fuel into the bowl. I had some float problems on my Johnson 15 HP when I neglected to adjust the lower limit of the float travel - the float would drop but it would drop too far and get stuck in the lower position, thus never stopping fuel flow = flooding. Your problem above is different however the float still needs proper high and low adjustments.

Good luck.

CMOS

Thanks for the info CMOS.
As far as the needle, I didn't want to damage it, so I actually took the float off before bending the tab.

I do have a manual, (and I also checked the infamous and extremely informative "Leroysrambling.com" site) but neither had ANY float adjustment values or tips, other than saying to make sure it was parallel to the carb/bowl mating surface, which again can be flawed when the float tab is bent.

I will do more research and see if I can put my eyes on some concrete values on the up and down travel of the float. (I'd love to get there without having to pull the carb out and disassemble it 5 times!) lol thanks again!

Why do you feel those instructions "can be flawed"? Bending the tab only changes the position of the float with respect to the fuel present in the bowl. The "up" flat adjustment is simple - level with (or 1-2 degrees above, with carb upsidedown) the carb body surface.

Here's a page from my 82 manual, which I THINK will hold over for your 79:



The measurement "3" should be 1-1/8 - 1-1/2". This is of course with the carb in the upright position. Let me know if this helps.

CMOS

(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.

CMOS said:

Why do you feel those instructions "can be flawed"? Bending the tab only changes the position of the float with respect to the fuel present in the bowl. The "up" flat adjustment is simple - level with (or 1-2 degrees above, with carb upsidedown) the carb body surface.

Here's a page from my 82 manual, which I THINK will hold over for your 79:

View attachment 15478

The measurement "3" should be 1-1/8 - 1-1/2". This is of course with the carb in the upright position. Let me know if this helps.

CMOS

Click to expand...

Now THAT's helpful info and exactly what I was looking for..... Some kind of measurement!
I guess I have the wrong manual, mine doesn't show these graphs (I am using the 1976 Johnson outboards 9.9hp service manual, and it doesn't give ANY info on float adjustment other than the "parallel thingie" mention..

Thanks a million I will take this measurement with carb upright (which makes more sense to me than working on the upside down position) and will let you know how it turns out...

J.D.

Jupiter Dinghy said:

Now THAT's helpful info and exactly what I was looking for..... Some kind of measurement!
I guess I have the wrong manual, mine doesn't show these graphs (I am using the 1976 Johnson outboards 9.9hp service manual, and it doesn't give ANY info on float adjustment other than the "parallel thingie" mention..


J.D.

Click to expand...

Hmmm..just to be clear you need to do 2 adjustments..float level and float drop. Do the joereeves float level adjustment and the CMOS float drop adjustment. Float level is done upside down and drop is done right side up.

Edit..did the quote bssakwards

joereeves said:

(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.

Click to expand...

Will do thanks!

Sunkinmess said:

Hmmm..just to be clear you need to do 2 adjustments..float level and float drop. Do the joereeves float level adjustment and the CMOS float drop adjustment. Float level is done upside down and drop is done right side up.

Click to expand...

Thanks for the help! will do that hopefully before the week is over.....

What Happen?

Canadianwalleye said:

What Happen?

Click to expand...

wow!... had to try remembering what happened after one year! lol... and the problem was a completely out of whack slow speed needle adjustment.
I thought I had bottomed out before pulling out 1.5 turn, when in fact I had just encountered some resistance that led me to believe I had bottomed out, but I was maybe still 2 turns away from bottom!.... Of course after proper adjustment it ran like a champ, and still does!

Well done, Happy motoring

Thanks for the reply. I didn’t take any of my orifices out... I’m scared too hahaha. I’m starting to think this is what my problem is also. The slow orifice has an issue cause I can ref the engine high and it seems to run decent but once I idle down to a low rpm it Boggs and dies... blah. Third time taking these carbs apart now.