Idle Mixture Issue?

[DukesFin]

GM L6 250 cid, stringer electric shift outdrive, holley 3160 390cfm carb (Carb is brand new)...

Okay, got the carb on and engine timed. Book calls for an idle speed of 500 - 600 rpm. I have the idle dialed in at 600.

When I put the boat in gear, (just barely move the throttle enough to engage the outdrive), it dies, feeling and sounding like it is not getting enough fuel.

You would think to adjust the idle speed up to solve the problem, but I don't want to hear the "clunk" of the outdrive engaging get any louder (not that it is so loud it's a problem). I'd imagine I'd have to adjust it up to 800 to 1K rpm to solve the problem this way and I'm sure it would not take long to damage the lower unit by having it engage the gears at such a high rpm setting.

So, not wanting to damage the motor that has about 75 hours on it, I thought I'd run an idea of a solution and ask the question here...

Should I try adjusting the idle mixture screws or is there something I'm not doing right? There is NO smell of fuel and NO smoke at all when I'm in neutral, idling at the dock. I have not messed with the idle mixture screws from where they were set by Holley.

Right now, other than the problem mentioned above, the motor runs great and sounds AWESOME and I'd like it to be perfect.

 

[Zero Balance]

Re: Idle Mixture Issue?

You know, I have the same issue with my stringer. I idle about 650 to 7 due to this. I'm pretty happy with functions at this setting. I've done everything I can think of. If your ball gears arent in bad shape it shouldnt be too loud at 700. Try putting a vacum gauge on the intake and see if your fuel mixture is ok. Other than that I guess you'll just have to find a happy medium.

 

[KaGee]

Re: Idle Mixture Issue?

Are you using the dash tach as your point of reference or an external one?

 

[DukesFin]

Re: Idle Mixture Issue?

Dash tach is what I'm using.

I guess I should have spent the extra $$ on the fancy timing light, huh? The one with the digital readout...

Using my dash tach, @ 600rpms, it sounds PERFECT... Beautiful idle in neutral.

 

[mkpj1]

Re: Idle Mixture Issue?

Idle speed is set "in gear" "in the water" to my understanding.

That gives my boat about 750 to 800 out of gear and she shifts fine.

 

[DukesFin]

Re: Idle Mixture Issue?

Ah, good deal.

I guess I should wait to make this change until Friday, when I put my new 14 pitch prop on instead of the 19 I have on there right now!

Thanks!

 

[KaGee]

Re: Idle Mixture Issue?

Idle speed is set "in gear" "in the water" to my understanding.

Not according to the OMC factory manual.

The idle air adjustment is properly set in gear, under power.

I would not be using my dash tach to set idle RPM.

 

[mkpj1]

Re: Idle Mixture Issue?

thanks caveman! He is correct. thinking one thing and stating another. I did mean idle air which I still think is your problem. Need to be in gear to set idle and then follow manual for idle speed. I also agree with the separate tach. I have a multi unit that does dwell, RPM, volts,.....pretty cheap at an auto store.

sorry for the confusion.