Force 120 smokes

[4aces]

I have a 1996 19ft. viking with a 120 force outbd. How do I get this motor to stop smoking. Mix is 50:1 and burning 88 oct reg fuel. checked the plugs and theres (low hours) build up black colored crusty. beginning of season had the carbs redone. runs good at 5000 RPMS. Trolling speed 700-800 smokes alot. Any ideas? someone suggested to lean out the oil mixture. or get hotter plugs. If so will there be a risk of engine damage?

 

[clanton]

Re: Force 120 smokes

How does thermostat check?

 

[kev_79]

Re: Force 120 smokes

Don't lean out the oil! You might get away with it, but at the cost of labor or a new motor, it isn't worth the risk. It sounds to me like your idle air screw could be turned out about 1/2 a round more for each carb. This controls the fuel mixture at low speeds. This screw is going to be at the top of the carb, I believe on the force. Initial setting on almost all carbs is 1 1/2 turns out. Only other guess would be a sticking float. Take off the carb bowls to check this. Tell me how it turns out.

 

[4aces]

Re: Force 120 smokes

How about trying a diffrent oil. I have been using 2-stoke oil from mercury. Is there any other quality 2-stroke oil that might make my engine perform better

 

[kev_79]

Re: Force 120 smokes

all pretty much the same, from tech 2000, $4.96 at wally world to quicksilver at about 17 dollars a gallon. You can't tell a perfomance difference as far as I can tell, nor my friends. As long as it says TC-W3.

 

[markg]

Re: Force 120 smokes

Any 2 cycle O/B's I've had have always smoked. As far as I know, they're supposed to smoke some. I notice it more myself when the motor's trolling. If she's running good and you're not fouling plugs, I wouldn't change anything - just be sure you're getting the correct mix (50:1) consistently.

 

[inventor1]

Re: Force 120 smokes

two-stroke motor+force=lot's of smoke.<br />I have one and it smokes like a trash can fire, but it runs like a champ. kev79 had good advice: NEVER RUN LESS THAN 50:1.<br />more ok but not less. It might be your idle mixture screws. do as follows: turn screws clockwise untill they seat lightly. do this to both carbs, than turn out(counter- clockwise) ONE FULL TURN.<br />Start motor and get it to run reliably on lowest idle possible. than start w/the top carb and back out 1/8", do this to both carbs. continue to turn in 1/8" increments<br />waiting 10 seconds between turns until the motor starts to pop from lean mixture. Then turn the screws clockwise 3/16" and that should give you the closest to optimal low-speed setting. I hope this info will help.

 

[sony2001]

Re: Force 120 smokes

What plugs do you use?<br />How often do you decarbonize the motor?

 

[12Footer]

Re: Force 120 smokes

Be carefull with the hotter plugs. Go with the recommended plugs only, or "Holy Piston Syndrome" may result. The Force bible calls for Champion L76V or QL76V (resistive).<br />Aslo, Forces DO smoke,and require frequent decarbing, every 60-80 hours.<br />And do use wallyworld supertech or quicksilver. You WILL notice an improvement over Lubrimatic, Valvoline, and Penzoil on that particular engine. Wally world's oil and quicksilver act identicaly.

 

[quang]

Re: Force 120 smokes

i have a 120hp mercury force, it will smoke at low rpm/idle speed, you wont be able to stop it, its normal for a 2 stroke o/b..<br /><br />you can actually see the smoke coming out of the water (which can be a very bad thing for the fish)<br /><br />when i reverse out from the boat laucnch ramp, i get sufficated with the thick black smoke!!<br /><br /><br />but--<br /><br />it will run great at high rpm but will ALWAYS smoke at low rpm, if u constantly use low-rpm to troll, i'd suggest you getting a trolling motor..<br /><br />because 1, the force outboard makes too much noise and smokes up alot at low-rpm.. it shouldnt be used for trolling..

 

[JasonJ]

Re: Force 120 smokes

I had thought that you should never use a main motor to troll with unless its a 4 stroke because 2 strokes need to be in their powerband for the most longevity, and to cut down on fouling. Maybe I have been mis-informed?

 

[4aces]

Re: Force 120 smokes

I have gone over the messages and I appreciate the input. It has been an eye opening experience. <br /><br />Other then the smoking motor, I recently realized the partial cause of the smoke was due to the gas being sold at the boat dock. As soon as I went with there gas again. It started the effect of heavier white smoke and odor. (1) time prior to that I went with (Chevron *89) the effects where lighter smoke and less odor.<br /><br />That's not really the answer but it something to think about. <br /><br />I did notice something else this weekend. <br />there was smoke coming from the upper unit where it attaches to the powerhead. Does anyone have any input of that area? I'll see what my manual has illustrated. possibly re-torque.<br /><br />Next I will check the plugs, adjust the carbs, and look into a timing light for possible adjustment. <br /><br />Thanks !!!