idle adjustment

[HighTrim]

I have a 1993 us marine 120hp Force

Runs great at all speeds, but dies when shifting into neutral after a run, need some ideas. Running it on a 24' bayliner rendevous deck boat, anyone running on a similar boat? Want some top end speed comparisons

 

[emoney]

Re: idle adjustment

Out of curiousity, how is your top end, while you're waiting for someone knowledgeable to respond? That boat probably weights in the 4klb range?

 

[Nordin]

Re: idle adjustment

It should have 700-800rpm at idle in gear under load. That is about 1000-1200rpm in neutral.
Adjust the idle at the idlescreew on the timingtower.
The air/fuelmixturescreew on each carb should be 1-1,5 turn out from lightly seated. See the link/synk in the top posts.
NEVER have the air/fuel mixture leaner then 1 turn out. You can melt the pistons.
If you have to lean fuelmixture it can pop out when you go to gear.

 

[HighTrim]

Re: idle adjustment

Interesting, the low speed needles seem to run best at 3/4 out from seated. I can put them back at 1.

I have no tach, and doesn't seem to be charging as per onboard meter, so will have to test rectifier as well.

Clockwise on idle screw will raise RPMS correct?

 

[jerryjerry05]

Re: idle adjustment

Yes screwing in on the towershaft/screw/locknut.Will raise RPM's
Back it out to 1 turn.

Air screw.Warm motor,running,turn screw in till it just bucks,stalls then out 1/2 turn.
Or out to the 1 full turn.
You can install a volt meter.
In any positive lead.
Check it for voltage.Off and after it just starts,then as you run it past 3000 rpms.

If there is no changes on a hot battery,it's probably not charging.
CDI ignition . com ha stest procedures.

Get somekind of tach.Even a Tiny Tach will help.

 

[HighTrim]

Re: idle adjustment

Ended up having an exhaust leak at the gearcase causing the difficulty to fine tune.