1987 85 HP Force terrible gas millage Stalls at full Trottle

[lizlovesmike689]

i have an 87 force motor and at full throttle it will run for a couple of minutes and began to studer out to an stall unless i lower the throttle not mention the terrible gas millage it almost feels as is its getting to much fuel and will flood and kill off any spark but still not too sure any suggestions need to fix gotta get back on the water to catch some big crappie other then that the motor really pushing my boat to the good spots untill that happens

 

[7355hpchry]

Re: 1987 85 HP Force terrible gas millage Stalls at full Trottle

I'd check the fuel pump diaphragm and your primer bulb. Also look for fuel leaks around the carb area.

 

[Clinto]

Re: 1987 85 HP Force terrible gas millage Stalls at full Trottle

There are alot of things this could be. I have a 88' 85 hp also. I would check the fuel pump to see if the screen is pluged. It could also be your spark advance. I know the feeling your having the engine sounds good up to 75%throttle then when you push it that last little bit she really opens up. I personally didnt run mine all out like that. The reason being I would use alot more fuel wide open. You can save alot and get there just as fast at 3/4 throttle

 

[Matthew A.]

Re: 1987 85 HP Force terrible gas millage Stalls at full Trottle

Hello,
Not really sure what you mean by "terrible mileage". 85 hp. Force engines by their very design are not a fuel efficient motor. Anything above 2.5 or 2.7 mpg is considered excellent. Anything below...probably average as there are too many varibles to consider boat to boat as well as conditions of the waters where and when operated.
One word of advice with Force engines. They are very prone to piston damage. (meaning melting of the piston top) Should one run them WOT or at upper rpm range with an obstructed fuel supply which creates a "run lean" condition...beit clogged fuel filter, faulty fuel pump or air entering the fuel system by means of loose fuel fitting or low fuel tank or incorrect fuel/fix mixture and before you have time to react or know that it just happened...and you just burned a nice round hole through the piston top.
I would go through the entire fuel system looking for air leaks via loose fuel connections. I also highly reccomend checking the fuel levels in the carb float bowls. If it has been awhile...rebuild the fuel pump or at the very least inspect it. Check and or replace any fuel filters also. It never hurts.
If the problem is the engine dies when given full throttle, chances are it's either a lack of fuel or a timing issue as clinto mentioned or a fuel air mixture that is way out of adjustment. Should the motor stummble extremely hard then die or just stummble at all for that matter while going to WOT from idle then the fuel/air mixture is too rich. If it hesitates or coughs or hiccups while going to WOT from idle then the fuel/air mixture is too lean. Better a slightly rich condition then a lean one. Fuel is cheaper then having to rebuild the motor. If the motor is able to reach or get near it's WOT rpms for a matter of moments before dying, then the problem is most likely not an issue of fuel starvation but an electrical issue such a bad connection or a faulty CD pack or a bad or going bad ignition coil.
Too high a fuel level in the float bowls of the carbs can often lead to excessive fuel consumption as can low compression which I would also be sure to check.

 

[glenik]

Re: 1987 85 HP Force terrible gas millage Stalls at full Trottle

My 120 had identical symptoms. After reading multiple posts about stalling at WOT I decided to just replace the entire fuel system from the tank to the motor. I cleaned out the vent lines, replaced the primer bulb, added a new fuel filter and lines, cleaned out the carb bowls and replaced the diaphragm in the fuel pump. It all cost me about $75 and 3 hours. She runs like a top now. I can get her up to 43 mph with a mid pitch prop even at my altitude.

 

[ybbaw1]

Re: 1987 85 HP Force terrible gas millage Stalls at full Trottle

I own a 1987 85hp force outboard. Recently the engine ran acceptionlly well for the first hour. Then after quick shutdown the outboard would start, but when throttled fwd engine dies. This happened repeatedly. Had to be towed back to the boat ramp. Shop checked it out and said nothing was wrong? What gives?

 

[foodfisher]

Re: 1987 85 HP Force terrible gas millage Stalls at full Trottle

I own a 1987 85hp force outboard. Recently the engine ran acceptionlly well for the first hour. Then after quick shutdown the outboard would start, but when throttled fwd engine dies. This happened repeatedly. Had to be towed back to the boat ramp. Shop checked it out and said nothing was wrong? What gives?

You need to start your own thread. Anyway, maybe the idle speed adjustment screw vibrated loose.