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Causes of engine sneeze while starting?

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Georgiaboy67

Advanced Contributor
So after a year of running my E115eleua with warped carb float bowls I finally replaced all the bowls. After I did this I ran the engine and noticed my Rpms have noticeably dropped some. And now my engine sneezes when I start the engine. Only when I start though. The idle is not really rough at all, it's pretty smooth and steady, but it's low enough to where it sounds like it could die at any moment. and when I'm idling the engine doesn't sneeze. It only does it when I start the engine. Cold start or not. What can cause this? Could it also be tied with the issue of my idle Rpms have dropped?
 
All was well before you removed the carbs to replace the float chambers? Check the seal between the carburetor(s) and the intake manifold.
 
Yes all was well, now the engine dies when I trailer the boat. It loads up fine but when I pull back on the throttle she shuts off. And when I go from planing speed to idle the motor and boat shake. Only on the deceleration, last time it was one of my carbs not adjusted. The fun thing is finding which one if that's the case
 
To find which one....... with the engine running, and sneezing..... simply stick a couple fingers into the carburetor throat(s), acting as a manual choke to enrich the mixture. When the engine smooths out somewhat, you've found the guilty carburetor.
 
Well I stuck some fingers in the throats, no change in idle that I could tell. Idk if this has anything to do with it either, but normally, especially on a cold start.(2 weeks since I ran the boat) I have to push the key in to choke it, well I did that like I always have, only this time, the engine would not start, so I just turned the key without pushing the choke in and she fired right up. I found it quite odd.. someone suggested earlier that replacing all 4 warped float bowls could have messed with my timing a little bit and to do a good link and sync
 
I retired in 1991 BUT I assume that your 1997 115 Evinrude still incorporates having the throttle bodies separate from the actual carburetors? If so, there is no way your carburetor work could possibly affect the linkage, synchronization, or timing.

However, since a difference has popped up in the starting procedure since you changed those float chambers... and pushing the key in to engage the fuel primer system apparently floods the engine... I would assume that you have somehow changed the float level of at least one of the carburetors which would either allow one carburetor to flood or starve one cylinder.

While observing the carburetors, and pumping the fuel primer bulb up until it gets hard... does any of the carburetors have fuel flowing from it?
 
So just a bit of an update today was the first time I've been able to work on it. Y'all ain't gonna believe this but at my age I already have 2 herniated disks in my back. L4-L5, (mild) and L5-s1 which is pushing on my nerve causing this excruciating pain I've had since January. 21 years old and I already have this problem!! My luck is bad luck only. Anyhow, today, following the service manual directions, I turned all 4 carbs in nearly a quarter of a turn in, and it wasn't enough cause it got dark, but the Rpms went up about 50-100 Rpms maybe a bit more, I was getting just over 600 Rpms in neutral and now I'm getting just over 700 Rpms. Now the motor runs a tad smoother, and it didn't die while trailering like it has been. I'm on the right track! Tells me my float bowls were leaning the Engine out then, cause if these carbs were adjusted to spec I wouldn't be turning the carbs idle speed mixture screw in and it not sneezing at me when I turn the mixture needle in
 
Georgiaboy67 said:
I'm on the right track!
Click to expand...

99% of all my problems with those good ole' 2 strokers, have been carb related.
Latest one was my 76 always collecting that cream color goo in the prop hub and sometimes even coming out of the water hole on the foot, I was having more and more problems getting it started, particularly when hot.
I went through everything: Re-cleaned carb, replaced points/condensers/coils, readjusted timing, and after all that: No start. With a nice strong spark, and plenty fuel moving through the carb and into the chambers. Even re-checked compression, which was dead even at 110 on each cylinder.
Decided to do one last thing before seeking professional help (both mechanical and psychiatric): Replaced plugs with new ones, and the pup started right up!
That's when I realized I was fouling plugs like no tomorrow on that thing as a result of too rich a mix, and when I went back to the idle speed needle adjustment, I realized that in my fear to go too far in, and deform the pointy end of said needle, I was in fact stopping way too soon, as the tightness I felt was not the needle bottoming up but just the thread getting squeezed tighter inside the rubber ring/gasket....
So, after going ALL THE WAY in and backing 1.5 turn, I was in business!
Fine tuned the air/mix ratio with boat in water, and boy... feels like a brand new motor! Amazing what the right carburetor adjustment will do to these 2 strokes! lol
And guess what?.. no more goo coming out of the prop! :rolleyes:
 
(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note 1: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

Note 2: If the engine should be a three (3) cylinder engine with three (3) carburetors, start the adjustment sequence with the center carburetor.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
 
Ahh see that's what I wasn't sure of. I didn't know if I needed to turn one 1/8 turn in. Wait 15 seconds, then go to the next one and turn it 1/8 turn in, and so on for the other 2 carbs. Or if I needed to keep turning the needle in til it sneezes or spits, then back it out 1/8 turn and continue that process on the other 3.
 
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