86' Force 85hp will start and run only at full throttle

[Bco128]

I own an 86' force 85hp. I recently purchassed this with a burnt piston.i have replaced the piston.compression is good in all cylinders #2 is lower of course, being new but still testing in spec.i have checked all of my wireing,all seems in good condition,have replaced fuel lines wich were in bad condition.checked my choke and throttle settings on the carb,choke good needed to adjust throttle slightly.good fire good air,fresh fuel, new plugs.will only start and run if i block the throttle open, when i try to bring down to idle it dies, will not start without blockong throttle open.any ideas?

 

[St. Johns River Rat]

Re: 86' Force 85hp will start and run only at full throttle

I had the same problem some time back. Have you throughly cleaned the carb.? Sounds like the low speed idle system may be plugged. Easy to do. Just get a can of carb. cleaner and systematically<br />remove screws and fittings. Spay the living crap out of each orifice. Let it sit. Do it again. Some carbs get so plugged that you need to shove a fine wire through the tubes and ports. Some plugs can be removed (rare) and replacement of carb. is the only solution. <br />You may also have a flooding problem when you go from WOT to idle. Check you needle seat on the float mechanism.<br />Good luck.

 

[Bco128]

Re: 86' Force 85hp will start and run only at full throttle

Thanks for the infor River Rat. I did clean the carbs a bit but did not do as compleat a job as you have sugested. i was afraid to move anything out of adjustment causing further problems.are there any particular parts that i need to be careful of as far as not to remove or dissasemble.Thanks again for the info.

 

[Bco128]

Re: 86' Force 85hp will start and run only at full throttle

have an update.cleaned the carbs very well.seeing some improvement.i still have to start the motor at nearly full throttle however it is making a better attempt to start at a lower range, also it will now slow down to about 1/4 throttle before it dies out. not alot of smoke so in my thinking it likely isnt flooding but still a possibility.ill keep tinkerin with it going to go over the fuel system in the book again ...maybe i missed something.any other ideas?

 

[Bco128]

Re: 86' Force 85hp will start and run only at full throttle

seems like im talking to myself here.oh well guess i know that at least its an inteligent conversation,anyway.had a thought this morning.would a reed valve cause this problem?seems possible. will look into it.oh and dont be afraid to hop in with ideas anytime. i dont have rabies.....just athletes foot.

 

[Bco128]

Re: 86' Force 85hp will start and run only at full throttle

Just in case anyone is still keeping up with this post.I found my problem.I pulled my intake to look at the reed valves.they were in good shape.however i notice that there was a leak at one of the crank case bolts.I pulled it cleaned it off and put a dab od thread sealent on it.and put it back in and check the torque on all the others.runs great again.thanks for the options River Rat.Ill keep that in mind the next time i have a problem.

 

[St. Johns River Rat]

Re: 86' Force 85hp will start and run only at full throttle

Bco, <br /><br />Sorry you've had to talk to yourself for a while.<br />But was glad to hear that you solved your problem.<br />I would still give the carbs a once over and de-carb the motor. Cheap insurance.<br />See ya!