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Small engine sputtering problem
Posted: April 24th, 2011, 4:32 pm
by BrogensDuck
Yamaha 9.9 4 strk. Pulled it out after the winter's nap, re-fueled, cleaned carb (as much as an amateur can), changed oil, cleaned filter and got it going. While it will run for ever (seemingly) on low throttle, anything more than that gives me about 30 seconds of love then dies down to idle RPM, catches its breath and then slowly revs back up as if I were doing it with the tiller then another 30 seconds of love. At neutral position,WOT, I am still getting bluish white smoke. Every now and then it will pop, like it is spitting something out. Frankly, every time it pops, I wonder if that one pop is clearing the junk...not yet.
The fuel line is pretty old, so I am thinking of changing that, but wondering if there is more than just that will solve. I have put about a half tank (1 HR) of run time into it since cleaning, so I wonder if there is any amount more of gas I need to run through it. I am getting better throttle response now than I was early in the game, but still having to massage it a bit sometimes when it falls out on me.
Still a carb issue? Mixture problem? I see Mr Porter in my future telling me something stupid I did.
Any help would be much appreciated.
Re: Small engine sputtering problem
Posted: April 24th, 2011, 4:42 pm
by FUTCHCAIRO
LOOSEN THE FILLER CAP ON YOUR FUEL TANK, DRAIN CARB. BOWL,CHECK FUEL FILTER, CHECK FUEL LINE BE SURE IT CAN HANDLE ETHANOL FUEL, SEEMS LIKE SOME RUBBER FROM ONE OF THE ELEMENTS THE FUEL GOES THROUGH HAS SOME SPONGE RUBBER IN THE HIGH SPEED JET, BLOW OUT WITH AIR HOSE, JUST A FEW OF A HUNDRED THINGS THAT COULD BE WRONG.
PA
SEMPER FI
Re: Small engine sputtering problem
Posted: April 24th, 2011, 7:21 pm
by Jumptrout51
What Pa said.
Re: Small engine sputtering problem
Posted: April 24th, 2011, 8:30 pm
by Harmsway
Check fuel vent.
Re: Small engine sputtering problem
Posted: April 25th, 2011, 5:52 am
by SS-342
I'd put an additive in the gas. Star-Tron is my pick. Use two times the rec. dose for starters.
Re: Small engine sputtering problem
Posted: April 25th, 2011, 8:55 am
by BrogensDuck
Thanks...I will try those things and give it a rip again. The issue of the fuel line and air seems like it might be the case as I have never had to work so hard to get the fuel pumped from the tank to the engine prior to starting. Make sense?
Re: Small engine sputtering problem
Posted: April 25th, 2011, 9:51 am
by FUTCHCAIRO
IF YOU HAVE ACCESS TO AN AIR TANK YA MIGHT WANT TO BLOW OUT THE FUEL LINE FROM THE ENGINE TOWARD THE TANK AND SEE IF THAT HELPS.
Re: Small engine sputtering problem
Posted: April 25th, 2011, 10:45 am
by BrogensDuck
Great idea. Thanks
Re: Small engine sputtering problem
Posted: April 25th, 2011, 1:01 pm
by onefishtwofish
Sounds like it is starving and all the ideas are spoton to get it cleaned out. I am betting on ehtanol/fuel line issues. Is there a filter in this system?
Re: Small engine sputtering problem
Posted: April 25th, 2011, 1:32 pm
by Browning Slayer
onefishtwofish wrote:Sounds like it is starving and all the ideas are spoton to get it cleaned out. I am betting on ehtanol/fuel line issues. Is there a filter in this system?
De-carbing the motor with Sea Foam might help...
Re: Small engine sputtering problem
Posted: April 25th, 2011, 1:43 pm
by robbankston
Sharks R Us wrote:onefishtwofish wrote:Sounds like it is starving and all the ideas are spoton to get it cleaned out. I am betting on ehtanol/fuel line issues. Is there a filter in this system?
De-carbing the motor with Sea Foam might help...
Re: Small engine sputtering problem
Posted: May 16th, 2011, 9:02 pm
by BrogensDuck
Oil sensor and bad plugs...just in case anyone has similar issues. Waivel wins again.
Re: Small engine sputtering problem
Posted: May 18th, 2011, 10:29 pm
by reelcatch
Waivel is the man!!!