force 120 idle speed

[MrBo]

I have a 120hp, 1995 Force outboard. I am a novice mechanic, but I blew a head gasket and found that cylinder #1 had a busted ring. I bought a manual and proceeded to rebuid the power head. It is back together and I have broke it in and it seems to be doing fine. The problem I am still having is the idle speed in gear/idle in neutral. This has been a problem with this boat since I got it. Sometimes it runs okay, and then sometimes it continually dies if I don't give it gas real fast when putting it in to gear. During the rebuild process, I did nothing to the carbs except replace the gaskets. With the manual in hand, I did some adjustments to the carburetor and the linkage.<br />First I adjusted the carburetor tie bar linkage to synchronize the throttle valves (they were not synchronized). Next I made sure the hrotthle cam pick up point was correct. Next I checked the wide open throttle linkage adjustment was correct. I DID NOT check the ignition timing cranking or dynamic. I then went thru the idle mixture adjustment. I am not sure about this adjustment. I I followed the procedure and adjusted the top carb then the bottom. The top carb idle mixture screw ended up being 2 1/2 turns out and then I did the bottom and it ende up being only 3/4 turns out. This did not seem right, so I went back to initial settings (1 turn CCW out)and started by adjusting the bottom carb first and it ended up being 2 1/2 turns out and the top was 3/4 out. So I went back to initial settings and I adjusted the two carb together. Both carbs are now 1 3/4 turns out. I then adjusted the throttle so that the motor idles 700 RPM in gear (I was doing the above adjustment with the motor in gear and idling). When I put the motor in neutral, the idle speed was 1100 RPM. I went boating around and it seems like the idle speed in forward has now dropped to 500 RPM and idle in neutral is about 700 RPM. I have struggled with this for 6 years. Anyone have any ideas?

 

[lonewolf5347]

Re: force 120 idle speed

I HAVE A 94 FORCE 120 HAD THE SAME PROBLEM IT WOULD NOT IDLE ONE DAY GOOD ONE DAY BAD.TURN OUT IT WAS THE STATOR . THE STATOR PUTS OUT HIGH @LOW VOLTAGE ONE FOR IDLE ONE FOR TOP SPEED.THE FIRST THING I WOULD DO IS TO MAKE SHURE ALL CYLINDERS ARE FIRING OR THE NEXT TIME SHE WON;T IDLE CHECK THAT EACH CYLINDER IS WORKING CORRECT.AS FAR AS THE CARBS. 1 TURN ON EACH IS CORRECT.IF YOU WANT YOU CAN E MAIL ME WILLL SEND YOU A TROUBLE SHOOTING GUIDE THAT MIGHT HELP YOU OUT.lonewolf5347@cs.com

 

[MrBo]

Re: force 120 idle speed

Lonewolf,<br />You mention that one turn CCW is correct setting. According to the manual this is the starting point and from there they tell you to continue CCW until the idle drops and the motor does not run well. Then they say to go CW until it starts to run poorly. Then set the idle mixture screw 1/2 way. By following this procedure, I ended with the idle mixture screw 1 3/4 turns out. In regards to the idle it seems like it can change throughout the day. It really is difficult when trying to get up a young skier.<br />How would you go about checking the stator? In idle and high speed and what should the voltages be? Also, the manual says that the idle speed in gear should be set to 700-800 RPM and this is set by the Throttle stop screw. Is this correct? This is what I did, but by the throttle stop screw there is a note that says the throttle cable needs to be adjusted. I did not do this because I could not find a correct procedure. Did you find that on your motor that the idle speed in neutral was around 1000/1100 RPM when the idle speed in gear is 700/800. <br />I will be running the boat today so I will have more information.<br />I will e-mail you so that you can forward the troubleshooting guide.<br />Thanks for the help

 

[sony2001]

Re: force 120 idle speed

Mr. Bo on my 88, 125 hp there are Tillotson CO,WB,or TC carbs. I adjusted them and the shop adjusted them. Both times the top runs at 1/2 turn and the bottom at 9/16 turn. If you have 700 to 900 rpm then thats fine. Then adjust the idle speed [tower shaft] so it won't stall going into and in gear.

 

[billum]

Re: force 120 idle speed

I have a 120 1990 Force and have had this problem since day one. Nobody including me can fix it. I have to shift fast from neutral to forward or it will die, and it is bad when loading on trailer or as you say pulling a young skier. <br />I am in the process of an overhaul as my third cylinder is out. My problem is getting the block separated at the crank.<br />Did you have any problem? See my question earlier in the day. Thanks

 

[MrBo]

Re: force 120 idle speed

First thing this morning after it was started it died when it was put into gear. I warmed up the engine and then put some locktite on the screw for the throttle cam roller and adjusted the RPM to 700/800 based on the advice of an earlier posting. The idle speed in neutral was around 1000/1100. The boat ran as good as it has in awhile. The idle in neutral though will fall to 700 sometime through out the day, and when I put it in gear I can see the RPM's drop to 400 and I have to give it gas or it will die.<br /><br />I noticed Billum has had this problem and today I had 10 kids between the ages of 8 and 16 that I was pulling around and trying to teach some of them to ski. I just wonder if this is somewhat the nature of the beast.<br /><br />What is the typical idle speed in neutral and does the RPM on most motors drop off when shifting out of neutral to idle speed in gear?

 

[sony2001]

Re: force 120 idle speed

MrBo; yes the rpm should rise in neutral but about 100rpm. If your rpm falls 400rpm when in gear it tells me that one carb is is dominate. They are not set equally.<br />When adj. the idle mixtures the idle speed screw on the tower must be ineffective [unscrewed],so the carbs are at dead slow.<br />Another observation on my set up is that the book says to place the roller by the mark on the cam for idle,[good] then check the butterfly valves at WOT to be fully open and adjust. If you do that it may change your first setting,so don't. Idle is more important than WOT.<br />Once both carbs are working equally at dead slow then raise the rpm on the tower enough to take the load of going into gear. 150 rpm

 

[DougG]

Re: force 120 idle speed

My 1993 120 Force also had idling problems from day one. Then after 7 years the stator went out and the motor would not run at all. The new dealer supplyed pricey stator was a change over kit that fit many Merc applications. Many extra parts and somewhat involved to install. After install what a difference, wonderful idle, tachometer worked right, spark plugs last longer, Like the motor should have run when new. The new stator also provides more battery charging amps. I don't think the original Force stator was up to par.

 

[LeeWater]

Re: force 120 idle speed

Just purchased a used boat with an 89 Force 150HP. During test run, motor ran great !!<br />Since then, I had several episodes of stalling at idle and while in neutral. <br /> Don't have my manual yet, so I took it in the shop yesterday. Glad to see DougG and Sony2001 has great tips and solutions. Hope I don't get soaked for this shop repair !!<br /> DougG, your story is good news. I was getting somewhat upset at my recent boat purchase, reading all the Force idle and stalling problems. I'll keep you all updated on my shop repairs.

 

[lonewolf5347]

Re: force 120 idle speed

I OWN A 120HP. FORCE 1994 WENT THREW FROM DAY OND 3 STATORS @ 2 SWITCH BOXES.THIS ENGINE @ THE MERC. HAVE THIS PROBLEM; WHICH ARE THE MERC. STATORS .JUST REPLACED THE STATOR WITH CDI THAT KNOW MAKES THIS ITEM.AND HAS A 2 YR. WARRENTY;AS FAR AS CHANGEING THE STATOR IT TAKES ABOUT 20MIN. TO DO THE JOB.THE COST OF THE STATOR WAS 173.00 NOT SO BAD IN PRICE.

 

[LeeWater]

Re: force 120 idle speed

Well, got the bad news on my 89 Force 150HP, today !!<br /><br />Called the shop and my motor needs an overhaul, at least thats what they say.<br />Cylinder #5 has no compression whats-so-ever, at least thats what they say.<br />What do you think, should I get a second opinion or should I just change my Stator, like DougG explained a few days ago.<br />The shop says I'm looking at about 1 G for the overhaul.

 

[sony2001]

Re: force 120 idle speed

LeeWater I'm sorry to hear the bad news. I would take it home, open the head and inspect. Rings, piston,and gasket. Show previous owner for some $ to be returned. May only be gasket.

 

[seaman]

Re: force 120 idle speed

if the motors running good and compession checks out ill bet you bent some linkage to the carbs or your throttle lever is slipping or something is out of wack pertaining to those parts in regards to billiums separation from block to manifold problem the old gaskets are sticking you need to make sure all the bolts are out there are some bolts i think there are 4 actually inside the manifold they are allen wrench type take em out and there might be some small allen bolts towards the bottom of the motor from the manifole to the block thats usually it use some Wd 40 around the edges if still sticks be careful not to dammge any thing

 

[LeeWater]

Re: force 120 idle speed

Thanks for the tips, Seaman & Sony2001.<br />Took the boat home, opened the head, inspected and gasket is in good shape, like new. Found a scored cylinder #5, not deep notches though !!!<br />Not sure, but would this cause zero compression in that chamber ????<br />Top of the piston #5 looks to be burned, like little holes ontop.<br />How do we check whether the stator is up to par??<br />DougG, above, talks about his experience with bad stator. <br />My question is: Are we all having problems with stators ???? I wonder.<br />I'm getting so so discourage, I'm checking out the prices on new motors. Quite pricy I may add.<br />Tips and answers anyone ????

 

[fkerks]

Re: force 120 idle speed

Doug G can you supply any more info on change over kit and the stator? part no. manufacturer,cost etc. Sounds like that may cure my prob. I did not realize so many other Force owners were experiencing the same prob. I have really been scratching my head. Glad I found this site.

 

[sony2001]

Re: force 120 idle speed

LeeWater. Time to go back to square one. You didn't double check the zero compression in #5. Put back head with new gasket, maybe old, borrow a compression guage Canadian Tire, and write down the psi of each cylinder. Zero comp is hard to belive! I,m thinking #5 is just not firing.<br />PS Lee you should start your own thread.

 

[seaman]

Re: force 120 idle speed

have you checked your reeds may be the floats are out of adjustment I just rebuilt my 120 and the mecahnic never said to sequence torque the head bolts results water in block no damge thoroughly cleaned still cranks over whew what a deal you might have some kind of clog in fuel line or filter sounds like its in the fuel system somwhere