Rough Idle in gear, 85Hp Force

[P7113t@aol.com]

I have an 1986 85 Force and are having problems at low speed in gear. Typical trolling speed is rough. The engine runs great at WOT and idles great at idle out of gear. I thought this may be caused by the mixture adjustments, however I have adjusted by the book and seem to still have the same issue. I do not feel I have adjusted the mixture properly because by turning the screws starting at 1 1/4 I see no difference. If you can assist on this issue it would be appreciated.

 

[brdhntr]

Re: Rough Idle in gear, 85Hp Force

Nature of the beast. Not designed to run at idle for long periods of time.

 

[chuckz]

Re: Rough Idle in gear, 85Hp Force

Try decarboning the engine with seafoam and then readjust your idle.

 

['96 Charger]

Re: Rough Idle in gear, 85Hp Force

My dads 85hp force was the same way. Had to coldstart it every time, yank it back, and slam it into gear.

 

[foodfisher]

Re: Rough Idle in gear, 85Hp Force

I wouldn't consider an 85hp engine a trolling motor.

 

[jerryjerry05]

Re: Rough Idle in gear, 85Hp Force

You have a tach?What is the idle set at?750-800 is idle in gear.
Check the compression/spark.Then check for water in the fuel.Look in the fuel pump for a bad diaphram.
If the air screws make no difference.Then I'd suggest taking the carbs apart and cleaning them.Get a manual and make sure they are set right.Air screw in till it stops(gently).Then out 1 and 1/8th.Then warm in the water in gear slowly turn in tuill it coughs then out 1/2 turn.Do all three.The idle needs to be at 750-800 to do this.
While the carbs are off look at the reeds.Any broken bent missing?
I used to troll in the Chesapeake Bay and had no trouble for years.
You need to keep fresh plugs and do a de-carb yearly.J

 

[Blackacid]

Re: Rough Idle in gear, 85Hp Force

What is "WOT", wide open throttle? I am having a similar issue, so I'm curious to see if what works for you.

Basically I can run at speed with no problem, but if I idle it back too much it will eventually die, and can be a pain in the aft to restart. Generally have to start it, and slam it into gear pretty quick.

If I let her sit for about 15-30 minutes, she'll start right back up without any problems.

 

[milehighboater]

Re: Rough Idle in gear, 85Hp Force

What is "WOT", wide open throttle? I am having a similar issue, so I'm curious to see if what works for you.

Basically I can run at speed with no problem, but if I idle it back too much it will eventually die, and can be a pain in the aft to restart. Generally have to start it, and slam it into gear pretty quick.

If I let her sit for about 15-30 minutes, she'll start right back up without any problems.

Sounds like the idle mixture, how does it start when it is cold?

 

[Blackacid]

Re: Rough Idle in gear, 85Hp Force

Sounds like the idle mixture, how does it start when it is cold?

Tends to start ok when cold, usually turns over the first couple of tries. When I got the boat (with motor) I was told the gas in it was pretty old. Rather than drain what was there, I topped off with premium and added some stabilizer.

Thus far I have only had it out at night; so I don't get to really run it that hard. I'm curious to see how it handles that though; and will find out in a week or two.

I did get my clymer's manual though. I'm going to adjust the idle mix before going. I just need to find a better tank to drop it down into.