98 Force 120 Stalling at idle

[geohei]

Hi, I'm new to the forum but have looked at many posts. I had a problem with my 120 stalling at idle speed which made docking very frustrating. A little history - I bought the rig last summer (98 Bayliner Capri 1800LS). It is in great shape. Looks like a 2 year old boat - if that. Anyway it ran fine until around Thanksgiving last year when it suddenly would not start. Took it to the shop and they replaced the trigger and stator. When I got it back it starts great but would stall during idle. I took it back because the throttle was messed up and mentioned the idle problem. They went over it and said they fixed it. But sure enough it stalled again. So I looked up "fixes" and found this forum. I tried the idle mix jets until I was blue in the face. No setting worked. Too lean the motor idle would surge. So I just set it running at 1200 rpm until it was smooth and steady. I started adjusting the idle speed screw near the flywheel until it ran in gear without stalling. So I'm running at 1000rpm in neutral and it drops to about 700rpm in gear (19" pitch prop). No stall!
Question - would replacing the stator and trigger mess up idle speed? GK

 

[Barnacle_Bill]

Re: 98 Force 120 Stalling at idle

It could if they messed with any of the linkage. Idle on an outboard is done with a procedure called link & sync. You need a manual to do it properly as there are certain steps that is must be done in.

 

[Frank Acampora]

Re: 98 Force 120 Stalling at idle

Replacing a trigger assembly CAN change timing so double check the shop's work.

HOWEVER: You messed with the carb low speed adjusting needles. BEFORE you run the engine on the water again, read at the top of the page: Sticky--FAQ synchronizing throttle and timing. Be certain the low speed needles are not set too lean.

 

[geohei]

Re: 98 Force 120 Stalling at idle

Thanks, I did check the sync and set between the two hash marks (I believe I read your procedure and got the general idea) then readjusted the low speed needles. I understand a "too lean" setting. I believe my idle speed was the problem - it was simply too low to handle the load especially from forward to reverse while docking. (19" pitch prop) What I did pick up from your excellent procedure is the "burble" I hear now at idle speed may mean I'm running a little rich. I'm set at about 1 1/4 out. I did find I was over adjusting the first time (1/4 - 1/2 turn and doing both carbs at the same time). I found these adjustments are somewhat course and your sticky says 1/8 turn. Wow, now I know why my adjustments were driving me crazy. Way too much...I am going to go back and verify everything per your sticky. I assume the 1998 120 has the same basic carb setup as the eariler models. Thanks again. GK
Update: I believe I adjusted the wrong screw for idle. It was the timing screw (which did raise the idle) and now I am probably too far advance for WOT. I could cause damage. I will reset the timimg back to where it was. The idle screw I found on another post and in the service manual (I just got my copy from a post). I'll adjust that to get the idle up slightly. Then I'll have the timing checked. GK

 

[geohei]

Re: 98 Force 120 Stalling at idle

Hello, I found my low speed jets are at 2 turns out or the idle "races" up and down. I corrected my idle adjustment per my other post. Just an FYI. Thanks, GK

 

[gprocks]

Re: 98 Force 120 Stalling at idle

Would you be able to link me to the post with the manual/ shematic. Mine runs great just need to get the idle right. A boat mechanic said it should idle at 800rpm, if you get too close to 1000rpm you could cause transmission damage. Or if you can email specs to gary@splitsecondmarketing.ca I would greatly appreciate it!

 

[Kalthe]

Re: 98 Force 120 Stalling at idle

For me also that manual/shematic. Have same kind of problems or adjustments to make. Thank you valkeavaadin@suomi24.fi