1993 Force 120hp idle speed

[ddzurik]

I have a 93 Force 120hp OB. A repair shop just rebuilt my carbs and fuel pump and got me running.
She screams at top end at 5000 rpm but when it idles in gear it kind of lugs and stalls. It will start
but you need to throw it in gear and jump on it to get her going. The mechanic said that it may need new cables
but shouldn't the low idle be set regardless of the throttle cable position? I saw an idle screw adjustment on the tower
that links the carbs to the timing advance. How far can I turn it up? The WOT timing is supposed to be 30 degrees, is there supposed to be a timing setting at idle of 750 RPM in gear? He also put in new NGK plugs and said the electrical checked out OK.
Thanks for any help.
Dave

 

[jerryjerry05]

Re: 1993 Force 120hp idle speed

You need to set the air screws first.The small screw with a spring on the side of the carb.
It should be set at 1 turn out from lightly seated.
The idle should be at 750-800 in gear motor warm.(set with the towershaft)
Don't mess with the timing right now.
If the mechnic didn;t touch it and you didn't touch it it should be ok.

Do a compression test.too.

 

[ddzurik]

Re: 1993 Force 120hp idle speed

mechanic said he set the idle at 1 3/4 to 1 7/8. He said better rich than lean.
I checked link and sync and the cam was not set on the roller per the manual. I reset
the cam roller and the tower link because at wot the throttle plates were past horizontal.

Also, how do you check wot cranking timing?
thanks
Dave

 

[jerryjerry05]

Re: 1993 Force 120hp idle speed

The "mechanic is wrong" They need to be set at 1 turn out. Then final adjustment they might get out another 1/8th to a 1/4 but not as far as the guy suggests.
The factory stated that the carbs should be set at 1 turn out and left there.
Now if you try to adjust the carb and it's not cooperating?? then somethings WRONG!

 

[Frank Acampora]

Re: 1993 Force 120hp idle speed

You do not adjust timing at idle. The timing is such that there is only a high speed adjustment. You only adjust idle speed using the idle stop screw on the timing tower. Your 93 should have Mercury controls. If it does, when you change the idle speed, you MUST re-adjust the throttle cable--it should say so right on the engine! This is one area where the original Chrysler/Force controls were better than Mercury (when used on a Force engine)

WOT timing is checked by placing the control handle in WOT. All four plugs are removed and grounded so as to not set up a feedback and possibly damage the CD unit, and the engine can not start. Use an inductive timing light clamped around the top plug wire. Crank the engine while aiming the light at the front of the flywheel. Flywheel marks should match the block pointer. Using the adjusting screw under the flywheel adjust timing to 28 degrees BTDC OR--whatever the flywheel or manual states. Merc. did set some different specs on some engines.

 

[ddzurik]

Re: 1993 Force 120hp idle speed

Frank and Jerry, thanks for the replies. Yes it has the merc 300 controls on it. My manual says to set timing at 30 deg and 32 at cranking wot. I will try it this weekend. I will set the carb screws at 1 turn and see where it idles at. I see where if I adjust the idle on the tower to
reset the cable to keep them from binding. Is it possible the stator could keep it from idling smooth? It ran good when I would throw it in gear and jump on it (past idle position). Most of the time it died when I put it in gear or slowed down to dock the boat.
Is there a simple stator test, resistance with an ohm meter? If the ohm readings are ok, can the stator still be bad?

 

[Frank Acampora]

Re: 1993 Force 120hp idle speed

What you are describing is a very common Force problem and usually not related to an ignition malfunction.

The major problems with Force engines stalling at idle are idle speed and fouled plugs. In fact, I carry a set of clean plugs. If I come across a Force owner having starting or stalling problems I give them the clean set and take the old plugs. It usually saves their day.

The first thing to do is to clean the plugs and re-install them. Then check the idle speed and adjust if it is too low. Idle must be 700-750 IN gear in the water. Higher pitch props will load the engine more than lower pitch props and lower idle speed.

 

[jerryjerry05]

Re: 1993 Force 120hp idle speed

Do this too.A compression test.
Outboard ignition . com (remove the spaces)
Or CDI ignition ,both have test procedures.

 

[Starcraft1709owner]

Re: 1993 Force 120hp idle speed

I need to lower my idle speed. Idling at ~1000 rpm in neutral now, about 900 in gear. With such a minor adjustment needed in idle speed, will I still need to adjust the cables?

 

[jerryjerry05]

Re: 1993 Force 120hp idle speed

Sometimes just adusting the slack from the cable, it will drop the idle?

 

[Starcraft1709owner]

Re: 1993 Force 120hp idle speed

How does one adjust the slack in the cable?