Evinrude 9.9 bogging down

[lynch_00]

Help... My 84 9.9 had a carb job about a year and a half ago, ran great... I ran the gas out of the carb and it sat in the garage over the winter... When I went to run it last week it spit and spuddered for a while and finally would run. At full throttle it revs up and down on its own and bogs on a full throttle start but eventually gets going. I dumped the fuel and put new fuel in the tank, tried sqirting some carb cleaning in the air intake, still runs the same... (the ball stays pumped up) oh yeah it seems to run smoother WOT with the Choke pulled out??? Do I need to have someone rebuild the carb every year? HELP

 

[petryshyn]

Re: Evinrude 9.9 bogging down

you don't have to rebuild the carb every year, if you run stabalizer in your last tank of the season, and leave the carb full of fuel. Do it once more, and next year, you'll be wiser.<br /><br />

 

[Joe Reeves]

Re: Evinrude 9.9 bogging down

CrappieBasser.... Even though the fuel is run out of the fuel system, there is still quite a bit of fuel lining the carb walls etc which will slowly drain down to the bottom of the carburetor area. Unfortunately, the brass fixed "High Speed" jet is located at the extreme bottom of the carb and it can become fouled quite easily. This would result in the surging that you've described. If while running under way, you pump the fuel primer bulb and the condition does not improve, in all probability the carb High Speed jet is clogged somewhat and will require cleaning.<br /><br />NOTE... Engines with a single carb can be run dry, using the choke in varing stages to draw out existing fuel within the fuel lines, pump, and carb, as the engine will stop running once it's out of fuel.<br /><br />However DO NOT run engines out of fuel that have more than one carb! The top carb will always run out of fuel first with the engine continuing to run on the other carbs. This results in a engine running with at least one aluminum piston running up and down a steel cylinder wall without lubrication (Not a good idea!)

 

[lynch_00]

Re: Evinrude 9.9 bogging down

is cleaning the High Speed Jet something that I should be able to do myself fairly easily? And if so, any tips on that?<br />Thanks<br /><br />PS Someone said that I could get some kind of 15HP carb kit that would make this thing scream... Is this true? IF so, are there any drawbacks and about how much would this run?

 

[tbird]

Re: Evinrude 9.9 bogging down

Schematic - <br />saw your post about running stabilizer in the last tank of the year and then leaving the carb full. Seems to go against everything I've heard about running the fuel lines etc. dry. 1) what is the reasoning for leaving carb full, and 2) how do you do it?

 

[petryshyn]

Re: Evinrude 9.9 bogging down

tbird<br />Lots of debate over this. Leaving a large amount of treated fuel in the carb prevents the residue left behind from drying fuel. It also is alot easier on fuel pump diaphrams as well.(they don't dry out, become brittel and contaminated) This ofcourse only applies to storing for a season (6 months max) <br /><br />I hate to say this over the net, but I've been running my 1978 70hp merc for 12 years and haven't done a carb or fuel pump till last year. The only reason I did the carbs was a rough idle condition which turned out to be exhaust leaking by the motor mounts. The carbs were as new inside. Murphy's law states that if you brag about your old fuel pumps, they'll fail the next season! I'll probably have them fail this summer...<br />Its easy to do, just partially choke the engine so it runs rough for a minute, then full choke to stall it. Stow it in the vertical position and fill up the carb with the primer ball. <br /><br />Anyway, thats been my experience. Others will have theirs. I guess the storage temperature plays a part as well(less evaporation in cooler temps)<br />

 

[petryshyn]

Re: Evinrude 9.9 bogging down

after seeing your "other" string and getting "all" your info, I agree with JB, drain the carb. If your using it so infrequently, its not a good idea to leave a full carb in hot weather for months and months...